Borax is a

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

( ionic compound), a

hydrated Drinking is the act of ingesting water or other liquids into the body through the mouth, proboscis, or elsewhere. Humans drink by swallowing, completed by peristalsis in the esophagus. The physiological processes of drinking vary widely among o ...

borate A borate is any of several boron oxyanions, negative ions consisting of boron and oxygen, such as orthoborate , metaborate , or tetraborate ; or any salt with such anions, such as sodium metaborate, and disodium tetraborate . The name also re ...

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...

, with

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

often written . It is a colorless crystalline solid, that dissolves in water to make a

basic BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Thomas E. Kurtz at Dartmouth College ...

solution Solution may refer to: * Solution (chemistry), a mixture where one substance is dissolved in another * Solution (equation), in mathematics ** Numerical solution, in numerical analysis, approximate solutions within specified error bounds * Solutio ...

. It is commonly available in powder or granular form, and has many industrial and household uses, including as a

pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and ...

, as a metal soldering

flux Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications to physics. For transport ...

, as a component of

glass Glass is a non- crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenchin ...

, enamel, and pottery glazes, for tanning of skins and hides, for artificial aging of wood, as a preservative against wood

fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately fr ...

, and as a pharmaceutic

alkalizer Alkalinizing agents are drugs used to manage disorders associated with low pH. For example, they may be used to treat acidosis due to kidney failure. Used for oral or parenteral therapy, sodium bicarbonate is the commonly preferred alkalinizing ...

. In chemical laboratories, it is used as a buffering agent. The compound is often called sodium tetraborate decahydrate, but that name is not consistent with its structure. The

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

is not

tetraborate In chemistry, tetraborate or pyroborate is an anion (negative ion) with formula ; or a salt containing that anion, such as sodium tetraborate, . It is one of the boron oxoacids, that is, a borate. The name is also applied to the hydrated ion a ...

but tetrahydroxy tetraborate , so the more correct formula should be . Informally, the product is often called sodium borate decahydrate or just sodium borate. The terms tincal "tinkle" and tincar "tinker" refer to native borax, historically mined from dry lake beds in various parts of Asia.

History

Borax was first discovered in dry lake beds in

Tibet Tibet (; ''Böd''; ) is a region in East Asia, covering much of the Tibetan Plateau and spanning about . It is the traditional homeland of the Tibetan people. Also resident on the plateau are some other ethnic groups such as Monpa people, ...

. Native tincal from Tibet,

Persia Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...

, and other parts of Asia was traded via the

Silk Road The Silk Road () was a network of Eurasian trade routes active from the second century BCE until the mid-15th century. Spanning over 6,400 kilometers (4,000 miles), it played a central role in facilitating economic, cultural, political, and rel ...

to the

Arabian Peninsula The Arabian Peninsula, (; ar, شِبْهُ الْجَزِيرَةِ الْعَرَبِيَّة, , "Arabian Peninsula" or , , "Island of the Arabs") or Arabia, is a peninsula of Western Asia, situated northeast of Africa on the Arabian Plat ...

in the 8th century AD. Borax first came into common use in the late 19th century when

Francis Marion Smith Francis Marion Smith (February 2, 1846 – August 27, 1931) (once known nationally and internationally as "Borax Smith" and "The Borax King" ) was an American miner, business magnate and civic builder in the Mojave Desert, the San Francisc ...

's Pacific Coast Borax Company began to market and popularize a large variety of applications under the 20 Mule Team Borax

trademark A trademark (also written trade mark or trade-mark) is a type of intellectual property consisting of a recognizable sign, design, or expression that identifies products or services from a particular source and distinguishes them from ot ...

, named for the method by which borax was originally hauled out of the California and Nevada deserts.

Etymology

The English word ''borax'' is Latinized: the

Middle English Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old Englis ...

form was ''boras'', from

Old French Old French (, , ; Modern French: ) was the language spoken in most of the northern half of France from approximately the 8th to the 14th centuries. Rather than a unified language, Old French was a linkage of Romance dialects, mutually intel ...

''boras, bourras''. That may have been from

Medieval Latin Medieval Latin was the form of Literary Latin used in Roman Catholic Western Europe during the Middle Ages. In this region it served as the primary written language, though local languages were also written to varying degrees. Latin functioned ...

''baurach'' (another English spelling), ''borac(-/um/em), borax'', along with

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...

''borrax'' (> ''borraj'') and

Italian Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance language *** Regional Ita ...

''borrace'', in the 9th century. The words ''tincal'' and ''tincar'' were adopted into

English English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ...

in the 17th century from Malay ''tingkal'' and from

Urdu Urdu (;"Urdu"
'' Persian

Arabic Arabic (, ' ; , ' or ) is a Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C. E.Watson; Walter ...

''tinkār/tankār''; thus the two forms in English. These all appear to be related to the

Sanskrit Sanskrit (; attributively , ; nominally , , ) is a classical language belonging to the Indo-Aryan languages, Indo-Aryan branch of the Indo-European languages. It arose in South Asia after its predecessor languages had Trans-cultural diffusion ...

टांकण ''ṭānkaṇa''.

Hydrates

The term ''borax'' properly refers to the so called decahydrate , more correctly written . However, the term may be applied also to the related compounds

Borax pentahydrate

Borax pentahydrate has the formula , more properly It is a colorless solid with density is 1.880 kg/m³ that crystallizes from water solutions above 60.8 °C in the rhombohedral crystal system. It occurs naturally as the mineral tinkhanite. It can be obtained by heating the decahydrate above 61 °C.

Borax dihydrate

Borax dihydrate has the formula , more properly . It can be obtained by heating the decahydrate or pentahydrate to above 116-120 °C.

Anhydrous borax

Anhydrous borax is sodium tetraborate proper, with formula . It can be obtained by heating any hydrate to 300 °C. It has one amorphous (glassy) form and three crystalline forms -- α, β, and γ, with melting points of 1015, 993 and 936 K respectively. α-Na2B4O7 is the stable form.

Chemistry

Structure

From the chemical perspective, borax contains the ₄O₅(OH)₄sup>2− ion. In this structure, there are two four-coordinate boron centers and two three-coordinate boron centers.

Physical properties

The crystalline decahydrate is a

proton conductor A proton conductor is an electrolyte, typically a solid electrolyte, in which H+ are the primary charge carriers. Composition Acid solutions exhibit proton-conductivity, while pure proton conductors are usually dry solids. Typical materials a ...

at temperatures above 21 °C. Conductivity is maximum along the ''b'' axis.

Reactions

Borax is also easily converted to

boric acid Boric acid, more specifically orthoboric acid, is a compound of boron, oxygen, and hydrogen with formula . It may also be called hydrogen borate or boracic acid. It is usually encountered as colorless crystals or a white powder, that dissolve ...

and other

s, which have many applications. Its reaction with hydrochloric acid to form boric acid is: : Na₂B₄O₇·10H₂O + 2 HCl → 4 H₃BO₃ + 2 NaCl + 5H₂O The "decahydrate" is sufficiently stable to find use as a

primary standard A primary standard in metrology is a standard that is sufficiently accurate such that it is not calibrated by or subordinate to other standards. Primary standards are defined via other quantities like length, mass and time. Primary standards are ...

for acid base titrimetry. Molten borax dissolves many metal oxides to form glasses. This property is important for its uses in metallurgy and for the

borax bead test The bead test is a traditional part of qualitative inorganic analysis to test for the presence of certain metals. The oldest one is the borax bead test or blister test. It was introduced by Berzelius in 1812.''Materials Handbook: A Concise Desktop ...

of qualitative chemical analysis.

Solubility

Borax is soluble in a variety of solvents; however, it is notably insoluble in ethanol.

Natural sources

Naturally occurring borax (known by the trade name Rasorite–46 in the United States and many other countries) is refined by a process of recrystallization. Hauling Borax, Death Valley, 1904

Uses

Ant control

Borax is used in control solutions because it is toxic to ants. Because it is slow-acting, worker ants will carry the borax to their nests and poison the rest of the colony.

Household products

Borax is used in various household laundry and cleaning products, including the 20 Mule Team Borax laundry booster, Boraxo powdered hand soap, and some

tooth bleaching Tooth whitening or tooth bleaching is the process of lightening the color of human teeth. Whitening is often desirable when teeth become yellowed over time for a number of reasons, and can be achieved by changing the intrinsic or extrinsic color o ...

formulas.

pH buffer

Borate ions (commonly supplied as boric acid) are used in biochemical and chemical laboratories to make buffers, e.g. for

polyacrylamide gel electrophoresis Polyacrylamide gel electrophoresis (PAGE) is a technique widely used in biochemistry, forensic chemistry, genetics, molecular biology and biotechnology to separate biological macromolecules, usually proteins or nucleic acids, according to their ...

of DNA and RNA, such as

TBE buffer TBE or Tris/Borate/EDTA, is a buffer solution containing a mixture of Tris base, boric acid and EDTA. In molecular biology, TBE and TAE buffers are often used in procedures involving nucleic acids, the most common being electrophoresis. Tris-acid ...

(borate buffered tris-hydroxymethylaminomethonium) or the newer SB buffer or BBS buffer (borate buffered saline) in coating procedures. Borate buffers (usually at pH 8) are also used as preferential equilibration solution in dimethyl pimelimidate (DMP) based crosslinking reactions.

Co-complexing agent

Water-softening agent

Borax alone does not have a high affinity for the '' hardness cations'', although it has been used for water-softening. Its chemical equation for '' water-softening'' is given below: : Ca²⁺_(aq) + Na₂ B₄ O_{7 (aq)} → Ca B₄ O_{7 (s)}↓ + 2 Na⁺_(aq) : Mg²⁺_(aq) + Na₂ B₄ O_{7 (aq)} → Mg B₄ O_{7 (s)}↓ + 2 Na⁺_(aq) The

ions introduced do not make water ‘hard’. This method is suitable for removing both temporary and permanent types of hardness.

Flux

Borax is also a good flux for "pre-tinning"

tungsten Tungsten, or wolfram, is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a new element in 1781 and first isol ...

with zinc — making the tungsten soft-solderable. Borax is often used as a flux for

forge welding Forge welding (FOW), also called fire welding, is a solid-state welding process that joins two pieces of metal by heating them to a high temperature and then hammering them together. It may also consist of heating and forcing the metals together ...

Small-scale gold mining

In artisanal gold mining, borax is sometimes used as part of a process known as the borax method (as a flux) meant to eliminate the need for toxic mercury in the gold extraction process, although it cannot directly replace mercury. Borax was reportedly used by gold miners in parts of the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

in the 1900s. There is evidence that, in addition to reducing the environmental impact, this method achieves better gold recovery for suitable ores and is less expensive. This borax method is used in northern

Luzon Luzon (; ) is the largest and most populous island in the Philippines. Located in the northern portion of the Philippines archipelago, it is the economic and political center of the nation, being home to the country's capital city, Manila, as ...

in the Philippines, but miners have been reluctant to adopt it elsewhere for reasons that are not well understood. The method has also been promoted in Bolivia and Tanzania.

Flubber

A rubbery polymer sometimes called Slime, Flubber, 'gluep' or 'glurch' (or erroneously called

Silly Putty Silly Putty is a toy based on silicone polymers that have unusual physical properties. It bounces, but it breaks when given a sharp blow, and it can also flow like a liquid. It contains a viscoelastic liquid silicone, a type of non-Newtonian f ...

, which is based on silicone polymers), can be made by cross-linking

polyvinyl alcohol Poly(vinyl alcohol) (PVOH, PVA, or PVAl) is a water- soluble synthetic polymer. It has the idealized formula H2CH(OH)sub>''n''. It is used in papermaking, textile warp sizing, as a thickener and emulsion stabilizer in polyvinyl acetate (PVAc) ...

with borax. Making flubber from

polyvinyl acetate Polyvinyl acetate (PVA, PVAc, poly(ethenyl ethanoate)), commonly known as wood glue, PVA glue, white glue, carpenter's glue, school glue, or Elmer's glue in the US, is a widely available adhesive used for porous materials like wood, paper, and ...

-based

glue Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advant ...

s, such as

Elmer's Glue Elmer's Products, or simply Elmer's is an American-based company that has a line of adhesive, craft, home repair, and office supply products. It is best known as the manufacturer of Elmer's Glue-All, a popular PVA-based synthetic glue, in ...

, and borax is a common elementary-science demonstration.

Food additive

Borax, given the

E number E numbers ("E" stands for "Europe") are codes for substances used as food additives, including those found naturally in many foods such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...

''E285'', is used as a

food additive Food additives are substances added to food to preserve Taste, flavor or enhance taste, appearance, or other sensory qualities. Some additives have been used for centuries as part of an effort to preserve food, for example vinegar (pickling), sal ...

, but is banned in some countries, such as

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...

and the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

. As a consequence, certain foods, such as

caviar Caviar (also known as caviare; from fa, خاویار, khâvyâr, egg-bearing) is a food consisting of salt-cured roe of the family Acipenseridae. Caviar is considered a delicacy and is eaten as a garnish or a spread. Traditionally, the te ...

, produced for sale in the United States contain higher levels of

to assist preservation. In addition to its use as a preservative, borax imparts a firm, rubbery texture to food. In

, borax ( or ) has been found in foods including wheat and rice noodles named In

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Gui ...

, it is a common, but forbidden, additive to such foods as noodles,

bakso Bakso or baso is an Indonesian meatball, or a meat paste made from beef surimi. Its texture is similar to the Chinese beef ball, fish ball, or pork ball. The word ''bakso'' may refer to a single meatball or the complete dish of meatball soup. '' ...

(meatballs), and steamed rice. When consumed with boric acid, numerous studies have demonstrated an inverse correlation between borax and various types of cancers. Boric acid and borax are low in toxicity for acute oral exposures, at approximately the same acute toxicity as salt. The average dose for asymptomatic ingestion cases, which accounts for 88% of all ingestions, is around 0.9 grams. However, the range of reported asymptomatic doses is wide, from 0.01 to 88.8 g.

Other uses

* Ingredient in enamel glazes * Component of

pottery Pottery is the process and the products of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures to give them a hard and durable form. Major types include earthenware, stoneware and ...

, and

ceramic A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain, ...

s * Used as an additive in ceramic slips and glazes to improve fit on wet, greenware, and bisque *

Fire retardant A fire retardant is a substance that is used to slow down or stop the spread of fire or reduce its intensity. This is commonly accomplished by chemical reactions that reduce the flammability of fuels or delay their combustion. Fire retardants ...

* Anti-fungal compound for

cellulose insulation Cellulose insulation is plant fiber used in wall and roof cavities to insulate, draught proof and reduce noise. Building insulation in general is low- thermal-conductivity material used to reduce building heat loss and gain and reduce noise tr ...

* Moth proofing 10% solution for wool * Pulverized for the prevention of stubborn pests (e.g.

German cockroach The German cockroach (''Blattella germanica''), colloquially known as the croton bug, is a species of small cockroach, typically about long. In color it varies from tan to almost black, and it has two dark, roughly parallel, streaks on the prono ...

es) in closets, pipe and cable inlets, wall

panelling Panelling (or paneling in the U.S.) is a millwork wall covering constructed from rigid or semi-rigid components. These are traditionally interlocking wood, but could be plastic or other materials. Panelling was developed in antiquity to make r ...

gaps, and inaccessible locations where ordinary

s are undesirable * Precursor for sodium perborate monohydrate that is used in

detergent A detergent is a surfactant or a mixture of surfactants with cleansing properties when in dilute solutions. There are a large variety of detergents, a common family being the alkylbenzene sulfonates, which are soap-like compounds that are m ...

s, as well as for

and other

s *

Tackifier Tackifiers are chemical compounds used in formulating adhesives to increase the tack, the stickiness of the surface of the adhesive. They are usually low-molecular weight compounds with high glass transition temperature. At low strain rate, they p ...

ingredient in

casein Casein ( , from Latin ''caseus'' "cheese") is a family of related phosphoproteins ( αS1, aS2, β, κ) that are commonly found in mammalian milk, comprising about 80% of the proteins in cow's milk and between 20% and 60% of the proteins in hum ...

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human die ...

and

dextrin Dextrins are a group of low-molecular-weight carbohydrates produced by the hydrolysis of starch and glycogen. Dextrins are mixtures of polymers of D-glucose units linked by α-(1→4) or α-(1→6) glycosidic bonds. Dextrins can be produced from ...

based adhesives * Precursor for

, a tackifier ingredient in

based adhesives * To make indelible ink for

dip pen A dip pen or nib pen or pen nib usually consists of a metal nib with capillary channels like those of fountain pen nibs, mounted in a handle or holder, often made of wood. Other materials can be used for the holder, including bone, metal and pla ...

s by dissolving

shellac Shellac () is a resin secreted by the female lac bug on trees in the forests of India and Thailand. It is processed and sold as dry flakes and dissolved in alcohol to make liquid shellac, which is used as a brush-on colorant, food glaze and ...

into heated borax * Curing agent for

snake Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more ...

skins * Curing agent for

salmon Salmon () is the common name for several commercially important species of euryhaline ray-finned fish from the family Salmonidae, which are native to tributaries of the North Atlantic (genus '' Salmo'') and North Pacific (genus '' Onco ...

eggs, for use in sport fishing for salmon * Swimming pool

buffering agent A buffer solution (more precisely, pH buffer or hydrogen ion buffer) is an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa. Its pH changes very little when a small amount of strong acid or base is ...

to control pH *

Neutron absorber In applications such as nuclear reactors, a neutron poison (also called a neutron absorber or a nuclear poison) is a substance with a large neutron absorption cross-section. In such applications, absorbing neutrons is normally an undesirable eff ...

, used in

nuclear reactor A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat fr ...

s and spent fuel pools to control reactivity and to shut down a nuclear chain reaction * As a

micronutrient Micronutrients are essential dietary elements required by organisms in varying quantities throughout life to orchestrate a range of physiological functions to maintain health. Micronutrient requirements differ between organisms; for example, huma ...

fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...

to correct boron-deficient soils. *

Preservative A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or b ...

taxidermy Taxidermy is the art of preserving an animal's body via mounting (over an armature) or stuffing, for the purpose of display or study. Animals are often, but not always, portrayed in a lifelike state. The word ''taxidermy'' describes the proc ...

* To color fires with a green tint * Was traditionally used to coat dry-cured meats such as hams to improve the appearance and discourage flies. * Used by

blacksmith A blacksmith is a metalsmith who creates objects primarily from wrought iron or steel, but sometimes from other metals, by forging the metal, using tools to hammer, bend, and cut (cf. tinsmith). Blacksmiths produce objects such as gates, gr ...

s in

* Used as a

for melting metals and alloys in

casting Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a ''casting'', which is ejecte ...

to draw out impurities and prevent

oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or ...

. * Used as a

woodworm A woodworm is the wood-eating larva of many species of beetle. It is also a generic description given to the infestation of a wooden item (normally part of a dwelling or the furniture in it) by these larvae. Types of woodworm Woodboring beetle ...

treatment (diluted in water) * In

Particle Physics Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) an ...

as an additive to

Nuclear emulsion A nuclear emulsion plate is a type of particle detector first used in nuclear and particle physics experiments in the early decades of the 20th century. https://cds.cern.ch/record/1728791/files/vol6-issue5-p083-e.pdf''The Study of Elementary Partic ...

, to extend the latent image lifetime of charged particle tracks. The first observation of the

pion In particle physics, a pion (or a pi meson, denoted with the Greek letter pi: ) is any of three subatomic particles: , , and . Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more gene ...

, which was awarded the 1950

Nobel Prize The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfr ...

, used this type of emulsion.

Toxicity

Borax, sodium tetraborate decahydrate, according to one study, is not acutely toxic. Its (median lethal dose) score is tested at 2.66 g/kg in rats, meaning that a significant dose of the chemical is needed to cause severe symptoms or death. The lethal dose is not necessarily the same for humans. On pesticide information websites it is listed as a non-lethal compound and of no hazardous concerns. Borax has been in use as an insecticide in the United States with various restrictions since 1946. All restrictions were removed in February 1986 due to the low toxicity of borax, as reported in two EPA documents relating to boric acid and borax. Although it cited inconclusive data, a re-evaluation in 2006 by the EPA still found that "There were no signs of toxicity observed during the study and no evidence of cytotoxicity to the target organ." In the reevaluation, a study of toxicity due to overexposure was checked and the findings were that "The residential handler inhalation risks due to boric acid and its sodium salts as active ingredients are not a risk concern and do not exceed the level of concern..." but that there could be some risk of irritation to children inhaling it if used as a powder for cleaning rugs. Sodium tetraborate decahydrate has no known hazard issues. Overexposure to borax dust can cause respiratory irritation, while no skin irritation is known to exist due to external borax exposure. Ingestion may cause gastrointestinal distress including

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of th ...

, persistent vomiting, abdominal pain, and

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...

. Effects on the vascular system and

human brain The human brain is the central organ of the human nervous system, and with the spinal cord makes up the central nervous system. The brain consists of the cerebrum, the brainstem and the cerebellum. It controls most of the activities of ...

include headaches and lethargy, but are less frequent. In severe cases, a "beefy" red rash affecting the palms, soles, buttocks and scrotum has occurred.

Possible carcinogen

The Indonesian Directorate of Consumer Protection warns of the risk of

liver cancer Liver cancer (also known as hepatic cancer, primary hepatic cancer, or primary hepatic malignancy) is cancer that starts in the liver. Liver cancer can be primary (starts in liver) or secondary (meaning cancer which has spread from elsewhere to th ...

with high consumption of borax over a period of 5–10 years.

Risk to fertility and pregnancy

Borax was added to the Substance of Very High Concern (SVHC) candidate list on December 16, 2010. The SVHC candidate list is part of the EU Regulations on the

Registration, Evaluation, Authorisation and Restriction of Chemicals Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) is a European Union regulation dating from 18 December 2006. REACH addresses the production and use of chemical substances, and their potential impacts on both human h ...

2006 (REACH), and the addition was based on the revised classification of borax as ''toxic for reproduction'' category 1B under the

CLP Regulation The CLP Regulation (for "Classification, Labelling and Packaging") is a European Union regulation from 2008, which aligns the European Union system of classification, labelling and packaging of chemical substances and mixtures to the Globally ...

s. Substances and mixtures imported into the EU which contain borax are now required to be labelled with the warnings "May damage fertility" and "May damage the unborn child". It was proposed for addition to REACH Annex XIV by the

ECHA The European Chemicals Agency (ECHA; ) is an agency of the European Union which manages the technical and administrative aspects of the implementation of the European Union regulation called Registration, Evaluation, Authorisation and Restrict ...

on July 1, 2015. If this recommendation is approved, all imports and uses of borax in the EU will have to be authorized by the ECHA. Review of the boron toxicity (as boric acid and borates) published 2012 in ''

Journal of Toxicology and Environmental Health The ''Journal of Toxicology and Environmental Health'' is a peer-reviewed public health journal covering environmental toxicology. It was established in 1975 and in 1998 was split into ''Part A: Current Issues'' and ''Part B: Critical Reviews''. Ac ...

'' concluded: "It clearly appears that human B oronexposures, even in the highest exposed cohorts, are too low to reach the blood (and target tissue) concentrations that would be required to exert adverse effects on reproductive functions." A draft risk assessment released by

Health Canada Health Canada (HC; french: Santé Canada, SC)Health Canada is the applied title under the Federal Identity Program; the legal title is Department of Health (). is the department of the Government of Canada responsible for national health poli ...

in July 2016 has found that overexposure to boric acid has the potential to cause developmental and reproductive health effects. Since people are already exposed to boric acid naturally through their diets and water, Health Canada advised that exposure from other sources should be reduced as much as possible, especially for children and pregnant women. The concern is not with any one product, but rather multiple exposures from a variety of sources. With this in mind, the department also announced that registrations for certain pesticides that contain boric acid, which are commonly used in homes, will have their registrations cancelled and be phased out of the marketplace. As well, new, more protective label directions are being introduced for other boric acid pesticides that continue to be registered in Canada (for example, enclosed bait stations and spot treatments using gel formulations).

References

S.Maričić, V.Pravdić, and Z.Veksli (1962): "Proton conductivity in borax, Na₂ ₄O₅(OH)₄8H₂O".''Journal of Physics and Chemistry of Solids'', volume 23, issue 11, pages 1651-1659. "American Borax Production" Scientific American September 22, 1877 Hildebrand, G. H. (1982) "Borax Pioneer: Francis Marion Smith." San Diego: Howell-North Books. p. 267 Chemical Age of India, Vol. 37, No.10 & 11 (1976) Borax decahydrate
borax.com C.M.G. Lattes, R.H.Fowler, and R.Cuer (1947): "Range-Energy Relation for Protons and a-Particles in the New Ilford 'Nuclear Research' Emulsions". ''Nature'', volume 159, pages 301-302 C.M.G.Lattes and G.P.S.Occhialini (1947): "Determination of the Energy and Momentum of Fast Neutrons in Cosmic Rays". ''Nature'', volume 159 (1947), , pages 331-332 Member state committee draft support document for identification of disodium tetraborate, anhydrous as a substance of very high concern because of its CMR properties
Adopted on June 9, 2010. Echa.europa.eu. Retrieved on February 17, 2012. Recommendation of the European Chemicals Agency of 1 July 2015 for the inclusion of substances in Annex XIV to REACH (List of Substances subject to Authorisation)
Echa.europa.eu. Retrieved on July 6, 2015. O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 1595 Mehmet Akgül and Osman Çamlıbe (2021) "The use of borax pentahydrate of inorganic filler in medium density fiberboard production". ''Maderas, Ciencia y tecnología'', volume 23, Epub 28-Ene-2021. Ömer Şahin and A. Nusret Bulutcu (2002)
"Dehydration Behaviour of Borax Pentahydrate to Anhydrous Borax by Multi-Stage Heating in a Fluidized"
''Turkish Journal of Chemistry'', volume 26, article 10, pages 89–96.

External links

* * (fused borax)

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