Chemical symbols are the abbreviations used in

chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...

, mainly for

chemical element A chemical element is a chemical substance whose atoms all have the same number of protons. The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8: each oxygen atom has 8 protons in its ...

s; but also for

functional group In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...

s, chemical compounds, and other entities. Element symbols for chemical elements, also known as atomic symbols, normally consist of one or two letters from the

Latin alphabet The Latin alphabet, also known as the Roman alphabet, is the collection of letters originally used by the Ancient Rome, ancient Romans to write the Latin language. Largely unaltered except several letters splitting—i.e. from , and from � ...

and are written with the first letter capitalised.

History

Earlier symbols for chemical elements stem from classical

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

and Greek words. For some elements, this is because the material was known in ancient times, while for others, the name is a more recent invention. For example, Pb is the symbol for

lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

(''plumbum'' in Latin); Hg is the symbol for mercury (''hydrargyrum'' in Greek); and He is the symbol for

helium Helium (from ) is a chemical element; it has chemical symbol, symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert gas, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is ...

Neo-Latin Neo-LatinSidwell, Keith ''Classical Latin-Medieval Latin-Neo Latin'' in ; others, throughout. (also known as New Latin and Modern Latin) is the style of written Latin used in original literary, scholarly, and scientific works, first in Italy d ...

name) because helium was not known in

ancient Roman In modern historiography, ancient Rome is the Roman people, Roman civilisation from the founding of Rome, founding of the Italian city of Rome in the 8th century BC to the Fall of the Western Roman Empire, collapse of the Western Roman Em ...

times. Some symbols come from other sources, like W for tungsten (''Wolfram'' in German) which was not known in Roman times. A three-letter temporary symbol may be assigned to a newly synthesized (or not yet synthesized) element. For example, "Uno" was the temporary symbol for hassium (element 108) which had the temporary name of ''unniloctium'', based on the digits of its atomic number. There are also some historical symbols that are no longer officially used.

Extension of the symbol

In addition to the letters for the element itself, additional details may be added to the symbol as superscripts or subscripts a particular

isotope Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemica ...

ionization Ionization or ionisation is the process by which an atom or a molecule acquires a negative or positive Electric charge, charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged at ...

, or oxidation state, or other atomic detail. A few isotopes have their own specific symbols rather than just an isotopic detail added to their element symbol. Attached subscripts or superscripts specifying a nuclide or molecule have the following meanings and positions: *The nucleon number (

mass number The mass number (symbol ''A'', from the German word: ''Atomgewicht'', "atomic weight"), also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. It is appro ...

) is shown in the left superscript position (e.g., ¹⁴N). This number defines the specific isotope. Various letters, such as "m" and "f" may also be used here to indicate a nuclear isomer (e.g., ^99mTc). Alternately, the number here can represent a specific spin state (e.g., ¹O₂). These details can be omitted if not relevant in a certain context. *The proton number (

atomic number The atomic number or nuclear charge number (symbol ''Z'') of a chemical element is the charge number of its atomic nucleus. For ordinary nuclei composed of protons and neutrons, this is equal to the proton number (''n''p) or the number of pro ...

) may be indicated in the left subscript position (e.g., ₆₄Gd). The atomic number is redundant to the chemical element, but is sometimes used to emphasize the change of numbers of nucleons in a nuclear reaction. *If necessary, a state of

or an

excited state In quantum mechanics Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Add ...

may be indicated in the right superscript position (e.g., state of ionization Ca²⁺). *The number of atoms of an element in a

molecule A molecule is a group of two or more atoms that are held together by Force, attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemi ...

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

is shown in the right subscript position (e.g., N₂ or Fe₂O₃). If this number is one, it is normally omitted - the number one is implicitly understood if unspecified. *A radical is indicated by a dot on the right side (e.g., Cl^• for a neutral chlorine atom). This is often omitted unless relevant to a certain context because it is already deducible from the charge and atomic number, as generally true for nonbonded valence electrons in skeletal structures. Many

s also have their own chemical symbol, e.g. Ph for the phenyl group, and Me for the methyl group. A list of current, dated, as well as proposed and historical signs and symbols is included here with its signification. Also given is each element's

, atomic weight, or the atomic mass of the most stable

, group and period numbers on the

periodic table The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows (" periods") and columns (" groups"). It is an icon of chemistry and is widely used in physics and other s ...

, and

etymology Etymology ( ) is the study of the origin and evolution of words—including their constituent units of sound and meaning—across time. In the 21st century a subfield within linguistics, etymology has become a more rigorously scientific study. ...

of the symbol.

Symbols for chemical elements

Symbols and names not currently used

The following is a list of symbols and names formerly used or suggested for elements, including symbols for placeholder names and names given by discredited claimants for discovery.

Systematic chemical symbols

These symbols are based on systematic element names, which are now replaced by trivial (non-systematic) element names and symbols. Data is given in order of:

, systematic symbol, systematic name; trivial symbol, trivial name. * 101: Unu, unnilunium; Md,

mendelevium Mendelevium is a synthetic chemical element; it has symbol Md ( formerly Mv) and atomic number 101. A metallic radioactive transuranium element in the actinide series, it is the first element by atomic number that currently cannot be produced ...

. * 102: Unb, unnilbium; No,

nobelium Nobelium is a synthetic element, synthetic chemical element; it has Chemical symbol, symbol No and atomic number 102. It is named after Alfred Nobel, the inventor of dynamite and benefactor of science. A radioactive metal, it is the tenth transura ...

. * 103: Unt, unniltrium; Lr, lawrencium. * 104: Unq, unnilquadium; Rf, rutherfordium. * 105: Unp, unnilpentium; Db, dubnium. * 106: Unh, unnilhexium; Sg, seaborgium. * 107: Uns, unnilseptium; Bh, bohrium. * 108: Uno, unniloctium; Hs, hassium. * 109: Une, unnilennium; Mt, meitnerium. * 110: Uun, ununnilium; Ds, darmstadtium. * 111: Uuu, unununium; Rg, roentgenium. * 112: Uub, ununbium; Cn, copernicium. * 113: Uut, ununtrium; Nh, nihonium. * 114: Uuq, ununquadium; Fl, flerovium. * 115: Uup, ununpentium; Mc,

moscovium Moscovium is a synthetic element, synthetic chemical element; it has Chemical symbol, symbol Mc and atomic number 115. It was first synthesized in 2003 by a joint team of Russian and American scientists at the Joint Institute for Nuclear Resea ...

. * 116: Uuh, ununhexium; Lv, livermorium. * 117: Uus, ununseptium; Ts,

tennessine Tennessine is a synthetic element; it has Chemical symbol, symbol Ts and atomic number 117. It has the second-highest atomic number and joint-highest atomic mass of all known elements and is the penultimate element of the Period 7 element, 7th ...

. * 118: Uuo, ununoctium; Og,

oganesson Oganesson is a synthetic element, synthetic chemical element; it has Chemical symbol, symbol Og and atomic number 118. It was first synthesized in 2002 at the Joint Institute for Nuclear Research (JINR) in Dubna, near Moscow, Russia, by a joint ...

. When elements beyond oganesson (starting with

ununennium Ununennium, also known as eka-francium or element 119, is a hypothetical chemical element; it has symbol Uue and atomic number 119. ''Ununennium'' and ''Uue'' are the temporary systematic element name, systematic IUPAC name and symbol respectivel ...

, Uue, element 119), are discovered; their systematic name and symbol will presumably be superseded by a trivial name and symbol.

Alchemical symbols

The following ideographic symbols were used in

alchemy Alchemy (from the Arabic word , ) is an ancient branch of natural philosophy, a philosophical and protoscientific tradition that was historically practised in China, India, the Muslim world, and Europe. In its Western form, alchemy is first ...

to denote elements known since ancient times. Not included in this list are spurious elements, such as the

classical element The classical elements typically refer to Earth (classical element), earth, Water (classical element), water, Air (classical element), air, Fire (classical element), fire, and (later) Aether (classical element), aether which were proposed to ...

fire Fire is the rapid oxidation of a fuel in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. Flames, the most visible portion of the fire, are produced in the combustion re ...

and

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

or phlogiston, and substances now known to be compounds. Many more symbols were in at least sporadic use: one early 17th-century alchemical manuscript lists 22 symbols for mercury alone. Planetary names and symbols for the metals – the seven planets and seven metals known since Classical times in Europe and the Mideast – was ubiquitous in alchemy. The association of what are anachronistically known as planetary metals started breaking down with the discovery of antimony, bismuth and zinc in the 16th century. Alchemists would typically call the metals by their planetary names, e.g. "Saturn" for lead and "Mars" for iron; compounds of tin, iron and silver continued to be called "jovial", "martial" and "lunar"; or "of Jupiter", "of Mars" and "of the moon", through the 17th century. The tradition remains today with the name of the element mercury, where chemists decided the planetary name was preferable to common names like "quicksilver", and in a few archaic terms such as lunar caustic (silver nitrate) and saturnism (lead poisoning).Maurice Crosland (2004) ''Historical Studies in the Language of Chemistry''

Daltonian symbols

The following symbols were employed by

John Dalton John Dalton (; 5 or 6 September 1766 – 27 July 1844) was an English chemist, physicist and meteorologist. He introduced the atomic theory into chemistry. He also researched Color blindness, colour blindness; as a result, the umbrella term ...

in the early 1800s as the periodic table of elements was being formulated. Not included in this list are substances now known to be compounds, such as certain rare-earth mineral blends. Modern alphabetic notation was introduced in 1814 by Jöns Jakob Berzelius; its precursor can be seen in Dalton's circled letters for the metals, especially in his augmented table from 1810. A trace of Dalton's conventions also survives in

ball-and-stick model In chemistry, the ball-and-stick model is a molecular model of a chemical substance which displays both the Molecular geometry, three-dimensional position of the atoms and the chemical bond, bonds between them. The atoms are typically represente ...

s of molecules, where balls for carbon are black and for oxygen red.

Symbols for named isotopes

The following is a list of isotopes which have been given unique symbols. This is not a list of current systematic symbols (in the Atom form); such a list can instead be found in Template:Navbox element isotopes. The symbols for isotopes of hydrogen, deuterium (D) and tritium (T), are still in use today, as is thoron (Tn) for radon-220 (though not actinon; An usually instead means a generic actinide).

Heavy water Heavy water (deuterium oxide, , ) is a form of water (molecule), water in which hydrogen atoms are all deuterium ( or D, also known as ''heavy hydrogen'') rather than the common hydrogen-1 isotope (, also called ''protium'') that makes up most o ...

and other deuterated solvents are commonly used in chemistry, and it is convenient to use a single character rather than a symbol with a subscript in these cases. The practice also continues with tritium compounds. When the name of the solvent is given, a lowercase d is sometimes used. For example, d-benzene or CD can be used instead of C The symbols for isotopes of elements other than hydrogen and radon are no longer used in the scientific community. Many of these symbols were designated during the early years of radiochemistry, and several isotopes (namely those in the decay chains of

actinium Actinium is a chemical element; it has chemical symbol, symbol Ac and atomic number 89. It was discovered by Friedrich Oskar Giesel in 1902, who gave it the name ''emanium''; the element got its name by being wrongly identified with a substa ...

, radium, and thorium) bear placeholder names using the early naming system devised by

Ernest Rutherford Ernest Rutherford, 1st Baron Rutherford of Nelson (30 August 1871 – 19 October 1937) was a New Zealand physicist who was a pioneering researcher in both Atomic physics, atomic and nuclear physics. He has been described as "the father of nu ...

Other symbols

* In Chinese, each chemical element has a dedicated character, usually created for the purpose (see Chemical elements in East Asian languages). However, in Chinese Latin symbols are also used, especially in formulas. General: *A: A deprotonated

acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

or an anion *An: any actinide *B: A base, often in the context of Lewis acid–base theory or Brønsted–Lowry acid–base theory *E: any element or

electrophile In chemistry, an electrophile is a chemical species that forms bonds with nucleophiles by accepting an electron pair. Because electrophiles accept electrons, they are Lewis acids. Most electrophiles are positively Electric charge, charged, have an ...

*L: any

ligand In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...

*Ln: any lanthanide *M: any

metal A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, electricity and thermal conductivity, heat relatively well. These properties are all associated wit ...

*Mm: mischmetal (occasionally used) *Ng: any

noble gas The noble gases (historically the inert gases, sometimes referred to as aerogens) are the members of Group (periodic table), group 18 of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn) and, in some ...

(Rg is sometimes used, but that is also used for the element roentgenium: see above) *Nu: any

nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are ...

*R: any unspecified radical ( moiety) not important to the discussion *St:

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

(occasionally used) *X: any halogen (or sometimes pseudohalogen) From organic chemistry: *Ac: acetyl – (also used for the element

: see above) *Ad: 1- adamantyl *All:

allyl In organic chemistry, an allyl group is a substituent with the structural formula . It consists of a methylene bridge () attached to a vinyl group (). The name is derived from the scientific name for garlic, . In 1844, Theodor Wertheim isolated a ...

*Am: amyl ( pentyl) – (also used for the element

americium Americium is a synthetic element, synthetic chemical element; it has Chemical symbol, symbol Am and atomic number 95. It is radioactive and a transuranic member of the actinide series in the periodic table, located under the lanthanide element e ...

: see above) *Ar: aryl – (also used for the element

argon Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abu ...

: see above) *Bn: benzyl *Bs: brosyl or (outdated) benzenesulfonyl *Bu: butyl (''i''-, ''s''-, or ''t''- prefixes may be used to denote ''iso''-, ''sec''-, or ''tert''- isomers, respectively) *Bz: benzoyl *Cp: cyclopentadienyl *Cp*: pentamethylcyclopentadienyl *Cy: cyclohexyl *Cyp: cyclopentyl *Et: ethyl *Me: methyl *Mes: mesityl (2,4,6-trimethylphenyl) *Ms: mesyl (methylsulfonyl) *Np: neopentyl – (also used for the element neptunium: see above) *Ns: nosyl *Pent: pentyl *Ph, Φ: phenyl *Pr: propyl – (''i''- prefix may be used to denote isopropyl. Also used for the element praseodymium: see above) *R: In organic chemistry contexts, an unspecified "R" is often understood to be an

alkyl In organic chemistry, an alkyl group is an alkane missing one hydrogen. The term ''alkyl'' is intentionally unspecific to include many possible substitutions. An acyclic alkyl has the general formula of . A cycloalkyl group is derived from a cy ...

group *Tf: triflyl (trifluoromethanesulfonyl) *Tr, Trt: trityl (triphenylmethyl) *Ts, Tos: tosyl (''para''-toluenesulfonyl) – (Ts also used for the element

: see above) *Vi: vinyl Exotic atoms: *Mu: muonium *Pn: protonium *Ps: positronium Hazard pictographs are another type of symbols used in chemistry.

Notes

References

Elementymology & Elements Multidict
element name etymologies. Retrieved July 15, 2005. *Atomic Weights of the Elements 2001

Retrieved June 30, 2005. Atomic weights of elements with atomic numbers from 1–109 taken from this source.

(2005).
WebElements Periodic Table
Retrieved June 30, 2005. Atomic weights of elements with atomic numbers 110–116 taken from this source. *Leighton, Robert B. ''Principles of Modern Physics''. New York: McGraw-Hill. 1959. *Scerri, E.R. "The Periodic Table, Its Story and Its Significance". New York, Oxford University Press. 2007.

External links

History of IUPAC Atomic Weight Values (1883 to 1997)
, American Chemical Society {{Portal bar, Chemistry, Biology, Physics, Science, Technology, Earth sciences, Education

Chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...

* pl:Symbol chemiczny