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Bismuth is a
chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, eleme ...
with the
symbol A symbol is a mark, sign, or that indicates, signifies, or is understood as representing an , , or . Symbols allow people to go beyond what is n or seen by creating linkages between otherwise very different s and s. All (and ) is achieved th ...
 Bi and
atomic number 300px, The Rutherford–Bohr model of the hydrogen atom () or a hydrogen-like ion (). In this model it is an essential feature that the photon energy (or frequency) of the electromagnetic radiation emitted (shown) when an electron jumps from one ...
83. It is a
pentavalent In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they und ...
post-transition metal The metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Electrical resistivity and con ...
and one of the
pnictogen A pnictogen ( or ; from grc, πνῑ́γω "to choke" and -gen, "generator") is any of the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an ...
s with chemical properties resembling its lighter
group 15 A pnictogen ( or ; from grc, πνῑ́γω "to choke" and -gen, "generator") is any of the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an ...
siblings
arsenic Arsenic is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same num ...

arsenic
and
antimony Antimony is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

antimony
. Elemental bismuth may occur naturally, although its
sulfide Sulfide (British English British English (BrE) is the standard dialect of the English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon England, early medieval England, whi ...

sulfide
and
oxide of rutile Rutile is a mineral composed primarily of titanium dioxide (TiO2), and is the most common natural form of TiO2. Other rarer polymorphs of TiO2 are known, including anatase, akaogiite, and brookite. Rutile has one of the highest re ...
form important commercial ores. The
free element In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they under ...
is 86% as dense as
lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate h ...

lead
. It is a brittle metal with a silvery-white color when freshly produced, but surface
oxidation (mild reducing agent) are added to powdered potassium permanganate Potassium permanganate is an inorganic compound with the chemical formula KMnO4 and composed of potassium ion, K+ and permanganate, . It is a purplish-black crystalline salt, ...

oxidation
can give it an
iridescent Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to Gradient, gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, ...
tinge in numerous colours. Bismuth is the most naturally
diamagnetic Diamagnetic materials are repelled by a magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experie ...
element and has one of the lowest values of
thermal conductivity The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by k, \lambda, or \kappa. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal c ...

thermal conductivity
among metals. Bismuth was long considered the element with the highest atomic mass that is stable, but in 2003 it was discovered to be extremely weakly
radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consid ...

radioactive
: its only
primordial isotope In geochemistry Geochemistry is the science Science (from the Latin word ''scientia'', meaning "knowledge") is a systematic enterprise that Scientific method, builds and Taxonomy (general), organizes knowledge in the form of Testability, ...
,
bismuth-209 Bismuth-209 (209Bi) is the isotope of bismuth with the longest known half-life of any radioisotope that undergoes α-decay (alpha decay). It has 83 protons and a magic number (physics), magic number of 126 neutrons, and an atomic mass of 208.9803987 ...

bismuth-209
, decays via
alpha decay
alpha decay
with a
half-life Half-life (symbol ''t''1⁄2) is the time required for a quantity to reduce to half of its initial value. The term is commonly used in nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents an ...
more than a
billion A billion is a number with two distinct definitions: *1,000,000,000 1,000,000,000 (one billion, short scale; one thousand million or milliard, yard, long scale) is the natural number In mathematics, the natural numbers are those used for ...
times the estimated
age of the universe In physical cosmology Physical cosmology is a branch of cosmology Cosmology (from Ancient Greek, Greek κόσμος, ''kosmos'' "world" and -λογία, ''-logia'' "study of") is a branch of astronomy concerned with the study of the chron ...
. Because of its tremendously long half-life, bismuth may still be considered stable for almost all purposes. Bismuth metal has been known since ancient times, although it was often confused with lead and tin, which share some physical properties. The etymology is uncertain, but the word may come from the German words ''weiße Masse'' or ''Wismuth'' ("white mass"), translated in the mid-sixteenth century to
New Latin New Latin (also called Neo-Latin or modern Latin) is the revival of Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, know ...
''bisemutum'' or ''bisemutium''. Bismuth compounds account for about half the production of bismuth. They are used in cosmetics; pigments; and a few pharmaceuticals, notably
bismuth subsalicylate Bismuth subsalicylate, sold as generic and under the brand name Pepto-Bismol, is an antacid elixir medication used to treat temporary discomforts of the stomach and gastrointestinal tract, such as nausea, heartburn, indigestion, upset stom ...

bismuth subsalicylate
, used to treat diarrhea. Bismuth's unusual propensity to expand as it solidifies is responsible for some of its uses, such as in casting of printing type. Bismuth has unusually low
toxicity Toxicity is the degree to which a chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects th ...

toxicity
for a heavy metal. As the toxicity of lead has become more apparent in recent years, there is an increasing use of bismuth alloys (presently about a third of bismuth production) as a replacement for lead.


Main uses

Bismuth compounds account for about half the production of bismuth. They are used in cosmetics; pigments; and a few pharmaceuticals, notably
bismuth subsalicylate Bismuth subsalicylate, sold as generic and under the brand name Pepto-Bismol, is an antacid elixir medication used to treat temporary discomforts of the stomach and gastrointestinal tract, such as nausea, heartburn, indigestion, upset stom ...

bismuth subsalicylate
, used to treat diarrhea. Bismuth's unusual propensity to expand as it solidifies is responsible for some of its uses, such as in the casting of printing type. Bismuth has unusually low
toxicity Toxicity is the degree to which a chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects th ...

toxicity
for a heavy metal. As the toxicity of lead has become more apparent in recent years, there is an increasing use of bismuth alloys (presently about a third of bismuth production) as a replacement for lead.


History and etymology

Bismuth metal has been known since ancient times; it was one of the first 10 metals to have been discovered. The name ''bismuth'' dates from around the 1660s and is of uncertain etymology; it possibly comes from obsolete
German German(s) may refer to: Common uses * of or related to Germany * Germans, Germanic ethnic group, citizens of Germany or people of German ancestry * For citizens of Germany, see also German nationality law * German language The German la ...

German
', ', ' (early 16th century), perhaps related to
Old High German Old High German (OHG, german: Althochdeutsch, German abbr. ) is the earliest stage of the German language The German language (, ) is a West Germanic language mainly spoken in Central Europe. It is the most widely spoken and official or c ...
' ("white"). The
New Latin New Latin (also called Neo-Latin or modern Latin) is the revival of Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, know ...
' (due to
Georgius Agricola Georgius Agricola (; born Georg Pawer or Georg Bauer; 24 March 1494 – 21 November 1555) was a German Humanist scholar, mineralogist Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal struct ...

Georgius Agricola
, who Latinized many German mining and technical words) is from the German ', perhaps from ', "white mass". The element was confused in early times with
tin Tin is a with the Sn (from la, ) and  50. Tin is a silvery-colored metal that characteristically has a faint yellow hue. Tin is soft enough to be cut with little force and a bar of tin can be bent by hand with little effort. When bent ...

tin
and lead because of its resemblance to those elements. Because bismuth has been known since ancient times, no one person is credited with its discovery.
Agricola AGRICOLA (AGRICultural OnLine Access) is an online database created and maintained by the United States National Agricultural Library of the United States Department of Agriculture. The database serves as the catalog and index for the collections ...

Agricola
(1546) states that bismuth is a distinct metal in a family of metals including tin and lead. This was based on observation of the metals and their physical properties. Miners in the age of alchemy also gave bismuth the name '','' or "silver being made," in the sense of silver still in the process of being formed within the Earth. Bismuth was also known to the
Incas The Inca Empire, also known as Incan Empire and the Inka Empire, and at the time known as the Realm of the Four Parts,,  "four parts together" was the largest empire in pre-Columbian America. The administrative, political and military ce ...

Incas
and used (along with the usual copper and tin) in a special bronze alloy for knives. Beginning with Johann Heinrich Pott in 1738,
Carl Wilhelm Scheele Carl Wilhelm Scheele (, ; 9 December 1742 – 21 May 1786) was a German and Swedish Pomerania Swedish Pomerania ( sv, Svenska Pommern; german: Schwedisch-Pommern) was a Dominion The word Dominion was used from 1907 to 1948 to refer to one of ...

Carl Wilhelm Scheele
, and
Torbern Olof Bergman Torbern Olaf (Olof) Bergman (''KVO'') (20 March 17358 July 1784) was a Swedish chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist A scientist is a person who conducts ...

Torbern Olof Bergman
, the distinctness of lead and bismuth became clear, and Claude François Geoffroy demonstrated in 1753 that this metal is distinct from lead and tin.


Characteristics


Physical characteristics

Bismuth is a brittle metal with a white, silver-pink hue, often with an
iridescent Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to Gradient, gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, ...
oxide An oxide () is a chemical compound A chemical compound is a chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having vol ...

oxide
tarnish showing many colors from yellow to blue. The spiral, stair-stepped structure of bismuth crystals is the result of a higher growth rate around the outside edges than on the inside edges. The variations in the thickness of the oxide layer that forms on the surface of the crystal cause different wavelengths of light to interfere upon reflection, thus displaying a rainbow of colors. When
burned Burned or burnt may refer to: * Anything which has undergone combustion * Burned (image), quality of an image transformed with loss of detail in all portions lighter than some limit, and/or those darker than some limit * Burnt (film), ''Burnt'' (fi ...
in
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

oxygen
, bismuth burns with a blue
flame A flame (from Latin ''wikt:en:flamma#Latin, flamma'') is the visible, gaseous part of a fire. It is caused by a highly exothermic chemical reaction taking place in a thin zone. Very hot flames are hot enough to have ionized gaseous components of ...

flame
and its oxide forms yellow fumes. Its
toxicity Toxicity is the degree to which a chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects th ...

toxicity
is much lower than that of its neighbors in the
periodic table The periodic table, also known as the periodic table of (the) chemical elements, is a tabular display of the chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is ...

periodic table
, such as
lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate h ...

lead
,
antimony Antimony is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

antimony
, and
polonium Polonium is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same numb ...

polonium
. No other metal is verified to be more naturally
diamagnetic Diamagnetic materials are repelled by a magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experie ...
than bismuth. (
Superdiamagnetism Superdiamagnetism (or perfect diamagnetism Diamagnetic materials are repelled by a magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. ...
is a different physical phenomenon.) Of any metal, it has one of the lowest values of
thermal conductivity The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by k, \lambda, or \kappa. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal c ...

thermal conductivity
(after
manganese Manganese is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical e ...

manganese
, and maybe
neptunium Neptunium is a chemical element with the Symbol (chemistry), symbol Np and atomic number 93. A radioactivity, radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after ...

neptunium
and
plutonium Plutonium is a radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material co ...

plutonium
) and the highest
Hall coefficient The Hall effect is the production of a voltage Voltage, electric potential difference, electric pressure or electric tension is the difference in electric potential The electric potential (also called the ''electric field potential'', ...

Hall coefficient
. It has a high
electrical resistivity Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that quantifies how strongly it resists electric current An electric current is a stream of charged particles, ...
. When deposited in sufficiently thin layers on a substrate, bismuth is a
semiconductor A semiconductor material has an value falling between that of a , such as metallic copper, and an , such as glass. Its falls as its temperature rises; metals behave in the opposite way. Its conducting properties may be altered in useful ways ...
, despite being a
post-transition metal The metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Electrical resistivity and con ...
. Elemental bismuth is in the liquid phase than the solid, a characteristic it shares with
germanium Germanium is a with the Ge and 32. It is a lustrous, hard-brittle, grayish-white in the , chemically similar to its group neighbors and . Pure germanium is a with an appearance similar to elemental silicon. Like silicon, germanium naturall ...

germanium
,
silicon Silicon is a chemical element with the Symbol (chemistry), symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a Tetravalence, tetravalent metalloid and semiconductor. It is a member ...

silicon
,
gallium Gallium is a chemical element with the Symbol (chemistry), symbol Ga and atomic number 31. Discovered by France, French chemist Paul-Émile Lecoq de Boisbaudran in 1875, Gallium is in boron group, group 13 of the periodic table and is ...

gallium
, and
water Water (chemical formula H2O) is an , transparent, tasteless, odorless, and , which is the main constituent of 's and the s of all known living organisms (in which it acts as a ). It is vital for all known forms of , even though it provide ...

water
. Wiberg, p. 768. Bismuth expands 3.32% on solidification; therefore, it was long a component of low-melting
typesetting on a composing stick on a type case. , letter founder, from the 1728 edition of '' Cyclopaedia, or an Universal Dictionary of Arts and Sciences, Cyclopaedia''. . Typesetting is the composition of Written language, text by means of arranging ph ...
alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Elec ...
s, where it compensated for the contraction of the other alloying components to form almost isostatic bismuth-lead eutectic alloys. Though virtually unseen in nature, high-purity bismuth can form distinctive, colorful hopper crystals. It is relatively nontoxic and has a low melting point just above 271 °C, so crystals may be grown using a household stove, although the resulting crystals will tend to be of lower quality than lab-grown crystals. At ambient conditions, bismuth shares the same layered structure as the metallic forms of
arsenic Arsenic is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same num ...

arsenic
and
antimony Antimony is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

antimony
, Wiberg, p. 767. crystallizing in the rhombohedral lattice (
Pearson symbol The Pearson symbol, or Pearson notation, is used in crystallography as a means of describing a crystal structure, and was originated by W.B. Pearson. The symbol is made up of two letters followed by a number. For example: * Diamond structure, ''cF'' ...
hR6,
space group In mathematics, physics and chemistry, a space group is the symmetry group of an object in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of an object that leave it unchan ...
Rm No. 166) of the trigonal crystal system. When compressed at room temperature, this Bi-I structure changes first to the
monoclinic In crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek language, Greek words ''crystallon'' " ...

monoclinic
Bi-II at 2.55 GPa, then to the
tetragonal In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the Cube (geometry), cube becomes a rectangular Pris ...

tetragonal
Bi-III at 2.7 GPa, and finally to the
body-centered cubic 200px, A network model of a primitive cubic system In crystallography, the cubic (or isometric) crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in cryst ...
Bi-V at 7.7 GPa. The corresponding transitions can be monitored via changes in electrical conductivity; they are rather reproducible and abrupt and are therefore used for calibration of high-pressure equipment.


Chemical characteristics

Bismuth is stable to both dry and moist air at ordinary temperatures. When red-hot, it reacts with water to make bismuth(III) oxide. : 2 Bi + 3 H2O → Bi2O3 + 3 H2 It reacts with
fluorine Fluorine is a chemical element with the Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard conditions for temperature and pressure, standard conditions as a highly toxic, pale yellow Diatomic molecule ...

fluorine
to make
bismuth(V) fluoride Bismuth pentafluoride is an inorganic compound with the formula BiF5. It is a white solid that is highly reactive. The compound is of interest to researchers but not of particular value. Structure BiF5 is polymeric and consists of linear chains ...
at 500 °C or bismuth(III) fluoride at lower temperatures (typically from Bi melts); with other
halogen The halogens () are a group A group is a number A number is a mathematical object used to counting, count, measurement, measure, and nominal number, label. The original examples are the natural numbers 1, 2, 3, 4, and so forth. Numbers can ...

halogen
s it yields only bismuth(III) halides. Wiberg, pp. 769–770. Greenwood, pp. 559–561. The trihalides are corrosive and easily react with moisture, forming oxyhalides with the formula BiOX.
Suzuki is a Japanese multinational corporation A multinational company (MNC) is a corporate A corporation is an organization—usually a group of people or a company A company, abbreviated as co., is a Legal personality, legal entity re ...
, p. 9.
: 4 Bi + 6 X2 → 4 BiX3 (X = F, Cl, Br, I) : 4 BiX3 + 2 O2 → 4 BiOX + 4 X2 Bismuth dissolves in concentrated
sulfuric acid Sulfuric acid (American spelling Despite the various English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English orthography English orthogra ...

sulfuric acid
to make bismuth(III) sulfate and
sulfur dioxide Sulfur dioxide (IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering OrganizationsNational Adhering Organizations in chemistry are the organizations that work as the autho ...
.
Suzuki is a Japanese multinational corporation A multinational company (MNC) is a corporate A corporation is an organization—usually a group of people or a company A company, abbreviated as co., is a Legal personality, legal entity re ...
, p. 8.
: 6 H2SO4 + 2 Bi → 6 H2O + Bi2(SO4)3 + 3 SO2 It reacts with
nitric acid Nitric acid (), also known as ''aqua fortis'' (Latin for "strong water") and spirit of niter, is a highly corrosive mineral acid. The pure compound is colorless, but older samples tend to acquire a yellow cast due to decomposition into nitroge ...

nitric acid
to make
bismuth(III) nitrate Bismuth(III) nitrate is a salt composed of bismuth in its cationic +3 oxidation state and nitrate anions. The most common solid form is the pentahydrate salt, hydrate. It is used in the synthesis of other bismuth compounds. It is available commercia ...
. : Bi + 6 HNO3 → 3 H2O + 3 NO2 + Bi(NO3)3 It also dissolves in
hydrochloric acid Hydrochloric acid +(aq) Cl−(aq) or H3O+ Cl− also known as muriatic acid, is an aqueous solution An aqueous solution is a solution Solution may refer to: * Solution (chemistry) Image:SaltInWaterSolutionLiquid.jpg, upMaking a salin ...

hydrochloric acid
, but only with oxygen present. : 4 Bi + 3 O2 + 12 HCl → 4 BiCl3 + 6 H2O It is used as a agent in the synthesis of alkaline-earth metal complexes: : 3 Ba + 2 BiPh3 → 3 BaPh2 + 2 Bi


Isotopes

The only primordial
isotope Isotopes are two or more types of atoms that have the same atomic number 300px, The Rutherford–Bohr model of the hydrogen atom () or a hydrogen-like ion (). In this model it is an essential feature that the photon energy (or frequency) of ...
of bismuth,
bismuth-209 Bismuth-209 (209Bi) is the isotope of bismuth with the longest known half-life of any radioisotope that undergoes α-decay (alpha decay). It has 83 protons and a magic number (physics), magic number of 126 neutrons, and an atomic mass of 208.9803987 ...

bismuth-209
, was traditionally regarded as the heaviest stable isotope, but it had long been suspected to be unstable on theoretical grounds. This was finally demonstrated in 2003, when researchers at the ''Institut d'Astrophysique Spatiale'' in
Orsay Orsay () is a commune An intentional community is a voluntary residential community designed from the start to have a high degree of group cohesiveness, social cohesion and teamwork. The members of an intentional community typically ho ...

Orsay
, France, measured the
half-life Half-life (symbol ''t''1⁄2) is the time required for a quantity to reduce to half of its initial value. The term is commonly used in nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents an ...
of to be (3 Bq/ M g), over a
billion A billion is a number with two distinct definitions: *1,000,000,000 1,000,000,000 (one billion, short scale; one thousand million or milliard, yard, long scale) is the natural number In mathematics, the natural numbers are those used for ...
times longer than the current estimated
age of the universe In physical cosmology Physical cosmology is a branch of cosmology Cosmology (from Ancient Greek, Greek κόσμος, ''kosmos'' "world" and -λογία, ''-logia'' "study of") is a branch of astronomy concerned with the study of the chron ...
. Owing to its extraordinarily long half-life, for all presently known medical and industrial applications, bismuth can be treated as if it is stable and nonradioactive. The radioactivity is of academic interest because bismuth is one of a few elements whose radioactivity was suspected and theoretically predicted before being detected in the laboratory. Bismuth has the longest known alpha decay half-life, although
tellurium-128 There are 39 known isotope Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. All isotopes of a given element have the same number of protons but different numbers of neut ...
has a
double beta decay In nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions. Other forms of nuclear matter are also studied. Nuclear physics should not be confused with atomic physics, which studi ...
half-life of over . Bismuth's extremely long half-life means that less than one-billionth of the bismuth present at the formation of the planet Earth would have decayed into thallium since then. Several isotopes of bismuth with short half-lives occur within the radioactive disintegration chains of
actinium Actinium is a chemical element In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behav ...

actinium
,
radium Radium is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical elem ...

radium
, and
thorium Thorium is a weakly radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration or nuclear disintegration) is the process by which an unstable atomic nucleus The atomic nucleus is the sma ...

thorium
, and more have been synthesized experimentally. Bismuth-213 is also found on the decay chain of
neptunium-237 Neptunium (93Np) is usually considered an artificial element, although trace quantities are found in nature, so a standard atomic weight The standard atomic weight (''A''r, standard(E)) of a chemical element Image:Simple Periodic Table Cha ...

neptunium-237
and
uranium-233 Uranium-233 (233U) is a fissile In nuclear engineering Nuclear engineering is the branch of engineering Engineering is the use of scientific method, scientific principles to design and build machines, structures, and other items, i ...

uranium-233
. Commercially, the radioactive isotope bismuth-213 can be produced by bombarding
radium Radium is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical elem ...

radium
with
bremsstrahlung ''Bremsstrahlung'' (), from "to brake" and "radiation"; i.e., "braking radiation" or "deceleration radiation", is electromagnetic radiation In physics Physics is the natural science that studies matter, its Elementary particle, fund ...

bremsstrahlung
photons from a
linear particle accelerator uses radio waves from a series of RF cavities at the start of the linac to accelerate the electron beam in bunches to energies of 100 MeV. A linear particle accelerator (often shortened to linac) is a type of particle accelerator , a synch ...
. In 1997, an antibody conjugate with bismuth-213, which has a 45-minute half-life and decays with the emission of an alpha particle, was used to treat patients with leukemia. This isotope has also been tried in cancer treatment, for example, in the targeted alpha therapy (TAT) program.


Chemical compounds

Bismuth forms trivalent and pentavalent compounds, the trivalent ones being more common. Many of its chemical properties are similar to those of
arsenic Arsenic is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same num ...

arsenic
and
antimony Antimony is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

antimony
, although they are less toxic than derivatives of those lighter elements.


Oxides and sulfides

At elevated temperatures, the vapors of the metal combine rapidly with oxygen, forming the yellow trioxide,

. Greenwood, p. 553. When molten, at temperatures above 710 °C, this oxide corrodes any metal oxide and even platinum. Krüger, p. 185 On reaction with a base, it forms two series of
oxyanionAn oxyanion, or oxoanion, is an ion An ion () is an atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyd ...
s: , which is polymeric and forms linear chains, and . The anion in is a cubic octameric anion, , whereas the anion in is tetrameric. The dark red bismuth(V) oxide, , is unstable, liberating

gas upon heating. The compound NaBiO3 is a strong oxidising agent. Greenwood, p. 578. Bismuth sulfide, , occurs naturally in bismuth ores. It is also produced by the combination of molten bismuth and sulfur. Bismuth oxychloride (BiOCl, see figure at right) and bismuth oxynitrate (BiONO3) stoichiometrically appear as simple anionic salts of the bismuthyl(III) cation (BiO+) which commonly occurs in aqueous bismuth compounds. However, in the case of BiOCl, the salt crystal forms in a structure of alternating plates of Bi, O, and Cl atoms, with each oxygen coordinating with four bismuth atoms in the adjacent plane. This mineral compound is used as a pigment and cosmetic (see below).


Bismuthine and bismuthides

Unlike the lighter
pnictogen A pnictogen ( or ; from grc, πνῑ́γω "to choke" and -gen, "generator") is any of the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an ...
s nitrogen, phosphorus, and arsenic, but similar to
antimony Antimony is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

antimony
, bismuth does not form a stable hydride. Bismuth hydride, bismuthine (), is an endothermic compound that spontaneously decomposes at room temperature. It is stable only below −60 °C. Bismuthides are intermetallic compounds between bismuth and other metals. In 2014 researchers discovered that sodium bismuthide can exist as a form of matter called a “three-dimensional topological Dirac semi-metal” (3DTDS) that possess 3D Dirac fermions in bulk. It is a natural, three-dimensional counterpart to graphene with similar electron mobility and velocity. Graphene and topological insulators (such as those in 3DTDS) are both crystalline materials that are electrically insulating inside but conducting on the surface, allowing them to function as transistors and other electronic devices. While sodium bismuthide () is too unstable to be used in devices without packaging, it can demonstrate potential applications of 3DTDS systems, which offer distinct efficiency and fabrication advantages over planar graphene in
semiconductor A semiconductor material has an value falling between that of a , such as metallic copper, and an , such as glass. Its falls as its temperature rises; metals behave in the opposite way. Its conducting properties may be altered in useful ways ...
and spintronics applications.


Halides

The halides of bismuth in low oxidation states have been shown to adopt unusual structures. What was originally thought to be bismuth(I) chloride, BiCl, turns out to be a complex compound consisting of Bi cations and BiCl and BiCl anions. The Bi cation has a distorted tricapped trigonal prismatic molecular geometry and is also found in , which is prepared by reducing a mixture of hafnium(IV) chloride and bismuth chloride with elemental bismuth, having the structure . Other polyatomic bismuth cations are also known, such as Bi, found in . Bismuth also forms a low-valence bromide with the same structure as "BiCl". There is a ''true'' monoiodide, BiI, which contains chains of units. BiI decomposes upon heating to the triiodide, Bismuth(III) iodide, , and elemental bismuth. A monobromide of the same structure also exists. In oxidation state +3, bismuth forms trihalides with all of the halogens: bismuth trifluoride, , bismuth(III) chloride, , bismuth tribromide, , and bismuth(III) iodide, . All of these except are hydrolyzed by water. Bismuth(III) chloride reacts with hydrogen chloride in diethyl ether, ether solution to produce the acid . The oxidation state +5 is less frequently encountered. One such compound is bismuth pentafluoride, , a powerful oxidizing and fluorinating agent. It is also a strong fluoride acceptor, reacting with xenon tetrafluoride to form the cation: : + →


Aqueous species

In aqueous solution, the Bi ion is solvated to form the aqua ion in strongly acidic conditions. At pH > 0 polynuclear species exist, the most important of which is believed to be the octahedral complex [].


Occurrence and production

In the Earth's crust, bismuth is about Abundances of the elements (data page), twice as abundant as gold. The most important ores of bismuth are bismuthinite and bismite. Native bismuth is known from Australia, Bolivia, and China. The difference between mining and refining production reflects bismuth's status as a byproduct of extraction of other metals such as lead, copper, tin, molybdenum and tungsten. World bismuth production from refineries is a more complete and reliable statistic. Bismuth travels in crude lead bullion (which can contain up to 10% bismuth) through several stages of refining, until it is removed by the Kroll-Betterton process which separates the impurities as slag, or the electrolytic Betts process. Bismuth will behave similarly with another of its major metals, copper. The raw bismuth metal from both processes contains still considerable amounts of other metals, foremost lead. By reacting the molten mixture with chlorine gas the metals are converted to their chlorides while bismuth remains unchanged. Impurities can also be removed by various other methods for example with fluxes and treatments yielding high-purity bismuth metal (over 99% Bi).


Price

The price for pure bismuth metal has been relatively stable through most of the 20th century, except for a spike in the 1970s. Bismuth has always been produced mainly as a byproduct of lead refining, and thus the price usually reflected the cost of recovery and the balance between production and demand. Demand for bismuth was small prior to World War II and was pharmaceutical — bismuth compounds were used to treat such conditions as digestive disorders, sexually transmitted diseases and burns. Minor amounts of bismuth metal were consumed in fusible alloys for fire sprinkler systems and Fuse (electrical), fuse wire. During World War II bismuth was considered a strategic material, used for solders, fusible alloys, medications and atomic research. To stabilize the market, the producers set the price at $1.25 per pound (2.75 $/kg) during the war and at $2.25 per pound (4.96 $/kg) from 1950 until 1964. In the early 1970s, the price rose rapidly as a result of increasing demand for bismuth as a metallurgical additive to aluminium, iron and steel. This was followed by a decline owing to increased world production, stabilized consumption, and the recessions of 1980 and 1981–1982. In 1984, the price began to climb as consumption increased worldwide, especially in the United States and Japan. In the early 1990s, research began on the evaluation of bismuth as a nontoxic replacement for lead in ceramic glazes, fishing sinkers, food-processing equipment, free-machining brasses for plumbing applications, lubricating greases, and shot for waterfowl hunting.
Suzuki is a Japanese multinational corporation A multinational company (MNC) is a corporate A corporation is an organization—usually a group of people or a company A company, abbreviated as co., is a Legal personality, legal entity re ...
, p. 14.
Growth in these areas remained slow during the middle 1990s, in spite of the backing of lead replacement by the United States federal government, but intensified around 2005. This resulted in a rapid and continuing increase in price.Bismuth Statistics and Information
see "Metal Prices in the United States through 1998" for a price summary and "Historical Statistics for Mineral and Material Commodities in the United States" for production. USGS.


Recycling

Most bismuth is produced as a byproduct of other metal-extraction processes including the smelting of lead, and also of tungsten and copper. Its sustainability is dependent on increased recycling, which is problematic. It was once believed that bismuth could be practically recycled from the soldered joints in electronic equipment. Recent efficiencies in solder application in electronics mean there is substantially less solder deposited, and thus less to recycle. While recovering the silver from silver-bearing solder may remain economic, recovering bismuth is substantially less so. Next in recycling feasibility would be sizeable catalysts with a fair bismuth content, such as bismuth phosphomolybdate. Bismuth used in galvanizing, and as a free-machining metallurgical additive. Bismuth in uses where it is dispersed most widely include certain stomach medicines (
bismuth subsalicylate Bismuth subsalicylate, sold as generic and under the brand name Pepto-Bismol, is an antacid elixir medication used to treat temporary discomforts of the stomach and gastrointestinal tract, such as nausea, heartburn, indigestion, upset stom ...

bismuth subsalicylate
), paints (bismuth vanadate), pearlescent cosmetics (bismuth oxychloride), and bismuth-containing bullets. Recycling bismuth from these uses is impractical.


Applications

Bismuth has few commercial applications, and those applications that use it generally require small quantities relative to other raw materials. In the United States, for example, 733 tonnes of bismuth were consumed in 2016, of which 70% went into chemicals (including pharmaceuticals, pigments, and cosmetics) and 11% into bismuth alloys. Some manufacturers use bismuth as a substitute in equipment for potable water systems such as valves to meet "lead-free" mandates in the U.S. (began in 2014). This is a fairly large application since it covers all residential and commercial building construction. In the early 1990s, researchers began to evaluate bismuth as a nontoxic replacement for lead in various applications.


Medicines

Bismuth is an ingredient in some pharmaceuticals, although the use of some of these substances is declining. * Bismuth subsalicylate is used as an diarrhea, antidiarrheal; it is the active ingredient in such "pink bismuth" preparations as Pepto-Bismol, as well as the 2004 reformulation of Kaopectate. It is also used to treat some other gastro-intestinal diseases like shigellosis and cadmium poisoning. The mechanism of action of this substance is still not well documented, although an oligodynamic effect (toxic effect of small doses of heavy metal ions on microbes) may be involved in at least some cases. Salicylic acid from hydrolysis of the compound is antimicrobial for toxogenic ''E. coli,'' an important pathogen in traveler's diarrhea. * a combination of
bismuth subsalicylate Bismuth subsalicylate, sold as generic and under the brand name Pepto-Bismol, is an antacid elixir medication used to treat temporary discomforts of the stomach and gastrointestinal tract, such as nausea, heartburn, indigestion, upset stom ...

bismuth subsalicylate
and bismuth subcitrate is used to treat the bacteria causing peptic ulcers. * Bibrocathol is an organic bismuth-containing compound used to treat eye infections. * Bismuth subgallate, the active ingredient in Devrom, is used as an internal deodorant to treat malodor from flatulence and feces. * Bismuth compounds (including sodium bismuth tartrate) were formerly used to treat syphilis * "Milk of bismuth" (an aqueous suspension of bismuth hydroxide and bismuth subcarbonate) was marketed as an alimentary cure-all in the early 20th century. * Bismuth subnitrate (Bi5O(OH)9(NO3)4) and bismuth subcarbonate (Bi2O2(CO3)) are also used in medicine.


Cosmetics and pigments

Bismuth oxychloride (BiOCl) is sometimes used in cosmetics, as a pigment in paint for eye shadows, hair sprays and nail polishes. This compound is found as the mineral bismoclite and in crystal form contains layers of atoms (see figure above) that refract light chromatically, resulting in an iridescent appearance similar to nacre of pearl. It was used as a cosmetic in ancient Egypt and in many places since. ''Bismuth white'' (also "Spanish white") can refer to either bismuth oxychloride or bismuth oxynitrate (BiONO3), when used as a white pigment. Bismuth vanadate is used as a light-stable non-reactive paint pigment (particularly for artists' paints), often as a replacement for the more toxic cadmium sulfide yellow and orange-yellow pigments. The most common variety in artists' paints is a lemon yellow, visually indistinguishable from its cadmium-containing alternative.


Metal and alloys

Bismuth is used in metal alloys with other metals such as iron. These alloys are used in automatic sprinkler systems for fires. It forms the largest part (50%) of Rose's metal, a fusible alloy, which also contains 25–28% lead and 22–25% tin. It was also used to make bismuth bronze which was used in the Bronze Age.


Lead replacement

The density difference between lead (11.32 g/cm3) and bismuth (9.78 g/cm3) is small enough that for many ballistics and weighting applications, bismuth can substitute for
lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate h ...

lead
. For example, it can replace lead as a dense material in fishing sinkers. It has been used as a replacement for lead in Shot (pellet), shot, bullets and less-lethal riot gun ammunition. The Netherlands, Denmark, England, Wales, the United States, and many other countries now prohibit the use of lead shot for the hunting of wetland birds, as many birds are prone to lead poisoning owing to mistaken ingestion of lead (instead of small stones and grit) to aid digestion, or even prohibit the use of lead for all hunting, such as in the Netherlands. Bismuth-tin alloy shot is one alternative that provides similar ballistic performance to lead. (Another less expensive but also more poorly performing alternative is "steel" shot, which is actually soft iron.) Bismuth's lack of malleability does, however, make it unsuitable for use in expanding hunting bullets. Bismuth, as a dense element of high atomic weight, is used in bismuth-impregnated latex shields to shield from X-ray in medical examinations, such as X-ray computed tomography, CTs, mostly as it is considered non-toxic. The European Union's Restriction of Hazardous Substances Directive (RoHS) for reduction of lead has broadened bismuth's use in electronics as a component of low-melting point solders, as a replacement for traditional tin-lead solders. Its low toxicity will be especially important for solders to be used in food processing equipment and copper water pipes, although it can also be used in other applications including those in the automobile industry, in the European Union, for example. Bismuth has been evaluated as a replacement for lead in free-machining brasses for plumbing applications, although it does not equal the performance of leaded steels.


Other metal uses and specialty alloys

Many bismuth
alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Elec ...
s have low melting points and are found in specialty applications such as solders. Many automatic sprinklers, electric fuses, and safety devices in fire detection and suppression systems contain the eutectic In19.1-Cd5.3-Pb22.6-Sn8.3-Bi44.7 alloy that melts at This is a convenient temperature since it is unlikely to be exceeded in normal living conditions. Low-melting alloys, such as Bi-Cd-Pb-Sn alloy which melts at 70 °C, are also used in automotive and aviation industries. Before deforming a thin-walled metal part, it is filled with a melt or covered with a thin layer of the alloy to reduce the chance of breaking. Then the alloy is removed by submerging the part in boiling water. Krüger, p. 183. Bismuth is used to make free-machining steels and free-machining aluminium alloys for precision machining properties. It has similar effect to lead and improves the chip breaking during machining. The shrinking on solidification in lead and the expansion of bismuth compensate each other and therefore lead and bismuth are often used in similar quantities. Similarly, alloys containing comparable parts of bismuth and lead exhibit a very small change (on the order 0.01%) upon melting, solidification or aging. Such alloys are used in high-precision casting, e.g. in dentistry, to create models and molds. Bismuth is also used as an alloying agent in production of malleable irons and as a thermocouple material. Bismuth is also used in aluminium-silicon cast alloys in order to refine silicon morphology. However, it indicated a poisoning effect on modification of strontium. Some bismuth alloys, such as Bi35-Pb37-Sn25, are combined with non-sticking materials such as mica, glass and Vitreous enamel, enamels because they easily wet them allowing to make joints to other parts. Addition of bismuth to caesium enhances the quantum yield of caesium cathodes. Krüger, p. 184. Sintering of bismuth and manganese powders at 300 °C produces a permanent magnet and magnetostrictive material, which is used in ultrasonic generators and receivers working in the 10–100 kHz range and in magnetic memory devices.
Suzuki is a Japanese multinational corporation A multinational company (MNC) is a corporate A corporation is an organization—usually a group of people or a company A company, abbreviated as co., is a Legal personality, legal entity re ...
, p. 15.


Other uses as compounds

* Bismuth is included in BSCCO (bismuth strontium calcium copper oxide) which is a group of similar superconducting compounds discovered in 1988 that exhibit the highest superconducting transition temperatures. * Bismuth subnitrate is a component of ceramic glaze, glazes that produces an iridescence and is used as a pigment in paint. * Bismuth telluride is a semiconductor and an excellent thermoelectric effect, thermoelectric material. Bi2Te3 diodes are used in mobile refrigerators, CPU coolers, and as detectors in infrared spectrophotometers. * Bismuth oxide, in its delta form, is a solid electrolyte for oxygen. This form normally breaks down below a high-temperature threshold, but can be electrodeposited well below this temperature in a highly alkaline solution. * Bismuth germanate is a scintillator, widely used in X-ray and gamma ray detectors. * Bismuth vanadate is an opaque yellow pigment used by some artists' oil, acrylic, and watercolor paint companies, primarily as a replacement for the more toxic cadmium sulfide yellows in the greenish-yellow (lemon) to orange-toned yellow range. It performs practically identically to the cadmium pigments, such as in terms of resistance to degradation from UV exposure, opacity, tinting strength, and lack of reactivity when mixed with other pigments. The most commonly-used variety by artists' paint makers is lemon in color. In addition to being a replacement for several cadmium yellows, it also serves as a non-toxic visual replacement for the older chromate pigments made with zinc, lead, and strontium. If a green pigment and barium sulfate (for increased transparency) are added it can also serve as a replacement for barium chromate, which possesses a more greenish cast than the others. In comparison with lead chromates, it does not blacken due to hydrogen sulfide in the air (a process accelerated by UV exposure) and possesses a particularly brighter color than them, especially the lemon, which is the most translucent, dull, and fastest to blacken due to the higher percentage of lead sulfate required to produce that shade. It is also used, on a limited basis due to its cost, as a vehicle paint pigment. * A catalyst for making acrylic fibers. * As an electrocatalyst in the conversion of CO2 to CO. * Ingredient in lubrication, lubricating grease (lubricant), greases. * In crackling microstars (dragon's eggs) in pyrotechnics, as the
oxide An oxide () is a chemical compound A chemical compound is a chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having vol ...

oxide
, Bismuth subcarbonate, subcarbonate or subnitrate. *As catalyst for the fluorination of arylboronic pinacol esters through a Bi(III)/Bi(V) catalytic cycle, mimicking transition metals in electrophilic fluorination.


Toxicology and ecotoxicology

:''See also bismuthia, a rare dermatological condition that results from the prolonged use of bismuth.'' Scientific literature indicates that some of the compounds of bismuth are less toxic to humans via ingestion than other heavy metals (lead, arsenic, antimony, etc.) presumably due to the comparatively low solubility of bismuth salts. Its biological half-life for whole-body retention is reported to be 5 days but it can remain in the kidney for years in people treated with bismuth compounds. Bismuth poisoning can occur and has according to some reports been common in relatively recent times.Data on Bismuth's health and environmental effects
Lenntech.com. Retrieved on 17 December 2011.
As with lead, bismuth poisoning can result in the formation of a black deposit on the gingiva, known as a bismuth line."Bismuth line"
in ''TheFreeDictionary's Medical dictionary''. Farlex, Inc.
Poisoning may be treated with dimercaprol; however, evidence for benefit is unclear. Bismuth's environmental impacts are not well known; it may be less likely to bioaccumulate than some other heavy metals, and this is an area of active research.


Bioremediation

The fungus ''Marasmius oreades'' can be used for the biological remediation of bismuth in polluted soils.


See also

* Lead-bismuth eutectic * List of countries by bismuth production * :Bismuth minerals, Bismuth minerals * Patterns in nature


References


Bibliography

* * * *


External links

* :File:Bismuth-501g.jpg, Laboratory growth of large crystals of Bismuth by Jan Kihle Crystal Pulling Laboratories, Norway
Bismuth
at ''The Periodic Table of Videos'' (University of Nottingham)
Bismuth breaks half-life record for alpha decay


{{Authority control Alchemical substances Bismuth, Chemical elements Minerals in space group 166 Native element minerals Pnictogens Post-transition metals Trigonal minerals Materials that expand upon freezing