borax

1. A hydrated sodium borate, Na₂B₄O₇·10H₂O, an ore of boron, that is used as a cleaning compound.
2. An anhydrous sodium borate used in the manufacture of glass and various ceramics.

[Middle English, from Medieval Latin bōrāx, from Arabic būraq, from Middle Persian būrak.]

Cheap merchandise, especially tasteless furnishings: “today's glinty borax” (New Yorker).

[Perhaps from the custom of giving away borax soap as a premium for the sale of cheap furniture.]

A colourless monoclinic solid, Na₂B₄O₇.10H₂O, soluble in water and very slightly soluble in ethanol; monoclinic; r.d. 1.73; loses 8H₂O at 75°C; loses 10H₂O at 320°C. The formula gives a misleading impression of the structure. The compound contains the ion [B₄O₅(OH)₄]²⁻ (see borate). Attempts to recrystallize this compound above 60.8°C yield the pentahydrate. The main sources are the borate minerals kernite (Na₂B₄O₇.4H₂O) and tincal (Na₂B₄O₇.10H₂O). The ores are purified by carefully controlled dissolution and recrystallization. On treatment with mineral acids borax gives boric acid.

Borax is a very important substance in the glass and ceramics industries as a raw material for making borosilicates. It is also important as a metallurgical flux because of the ability of molten borates to dissolve metal oxides. In solution it partially hydrolyses to boric acid and can thus act as a buffer. For this reason it is used as a laundry pre-soak. It is used medicinally as a mild alkaline antiseptic and astringent for the skin and mucous membranes.

Disodium tetraborate is the source of many industrially important boron compounds, such as barium borate (fungicidal paints), zinc borate (fire-retardant additive in plastics), and boron phosphate (heterogeneous acid catalyst in the petrochemicals industry).

In retailing, merchandise that appears to be of high quality but in fact is not. This type of merchandise is sometimes used in advertisements as a lead to bring customers into the store.

The sodium salt of boric acid.

Often a principal ingredient in casting fluxes. Used in gypsum products as a retardant for the setting reaction and a strengthener for hydrocolloids.

For more information on borax, visit Britannica.com.

A term used by many critics of streamlined, gaudy, ephemeral—particularly American—products in the years following the Second World War. Typical of this breed was American writer-curator Edgar Kaufmann Jr., who wrote a celebrated article entitled ‘Borax—or the Chromium-Plated Calf’ in the Architectural Review of October 1948. He warned British readers of the dangers of ephemeral design, obsolescence, and superficial styling, characteristics that were essentially antithetical to the Modernist aesthetic of clean, abstract forms and the tenets of ‘Good Design’. These were promulgated by organizations such as the Council of Industrial Design (see Design Council) in Britain, the Deutscher Werkbund in Germany, and the Museum of Modern Art in New York. ‘Borax’ is thought to derive from 1920s American slang for showy product promotions offered by the Borax soap company.

Borax (sodium tetraborate) became important in the European Middle Ages as a flux for soldering—that is, for cleaning the surfaces of metal pieces to be joined by being melted together. Native European sources were un-known, and the nature and origin of this mysterious material was long a puzzle to chemists. Borax was ultimately traced to Tibet—almost the only source known until the discovery (1776) and exploitation (1820) of Italian springs of boric acid (hydrogen tetraborate), which could be converted by the addition of soda (sodium carbonate) into borax. Italy became the principal source of borax until the 1860s, when desert areas now in Chile began to supply borax.

The key figure in the discovery of borax in North America was John A. Veatch, who found it in California in 1856, first in springs at the north end of the Sacramento Valley (Tehama County) and then in larger quantities in a cutoff bay of Clear Lake (Lake County). Veatch himself stated that the discovery was accidental, sparked by the presence in the region of an Englishman who had formerly worked for a London borax company. The California Borax Company was organized to exploit this source, and the company struggled for a decade to extract and purify a material encrusted on the bottom of an isolated wilderness lake. In 1857 Veatch's explorations took him to southern California, where he found borax in the waters of mud volcanoes in the Colorado desert. Within the next decade, borax was found in surface encrustations in more convenient locations in Nevada and southern California. In 1871 the Mining and Scientific Press of San Francisco reported borax to be "all the rage," with production in progress at Columbus, Fish, and Teal marshes in Esmeralda County, Nevada. In 1880 production began in Death Valley, California, where the famous twenty-mule-team wagons carried it out of this below-sea-level depression to the railroad junction at Mojave, 160 miles away.

These surface deposits of borax were largely sodium calcium tetraborate (ulexite), known from their appearance as cotton balls. Their conversion to true borax was chemically simple but difficult in practice. American producers mastered the conversion process by the mid-1880s and supplied the domestic and international markets. However, they drove the price down to a level that caused most producers to fail. The principal survivor, Francis "Borax" Smith, employed Stephen Mather to promote borax in 1896, starting with a pamphlet advertising two hundred "recipes" for borax. This successful advertising campaign greatly expanded the demand for borax, which had become relatively inexpensive, especially in washing powders, glass, and ceramic glazes.

Although Smith controlled nearly all American sources of borax, financial troubles with his other investments forced him to merge with the English borax company Redwood and Sons in 1896 to form a company known in the early 2000s as U.S. Borax. Exploitation of shallow deposits terminated once drilling began in the Mojave Desert, at a site marked by the company town, Boron. In the 1970s production there and at Searles Lake, California, exceeded one million tons per year and satisfied the borax demands of the United States, western Europe, Japan, and many other parts of the world.

Bibliography

Coolidge, Dane. Death Valley Prospectors. Morongo Valley, Calif.: Sagebrush Press, 1985.

Spears, John R. Illustrated Sketches of Death Valley and Other Borax Deserts of the Pacific Coast. Morongo Valley, Calif.: Sagebrush Press, 1977.

Travis, Norman J., and E. J. Cocks. The Tincal Trail: A History of Borax. London: Harrap, 1984.

—Robert P. Multhauf/H. S.

Environment

Dry lake beds in desert country.

Usually (especially with human assistance) forms crystals, often very large and well formed. Unfortunately they whiten and crumble to powder in the mineral cabinet. Also mixed with other compounds in crusts of various minerals in salt lake beds.

White, colorless but often stained by impurities; Luster glassy; hardness 2-2Ɖ; specific gravity 1.7; fracture conchoidal; cleavage 3, 1 good. Brittle; starts transparent to translucent, but crystals lose water and turn white.

Hydrous sodium borate (36.6% B ₂ O ₃ , 16.2% Na ₂ O, 47.2% H ₂ O)

Swells and fuses easily to a clear glass sphere that clings to the charcoal, coloring the flame yellow (this is the same borax bead used to test for metals in minerals). Water-soluble; tastes sweetish but astringent.

Not likely to be confused with any other mineral; characteristic fusion behavior will distinguish it from most minerals. Rapid whitening of the crystals confirms other tests.

Used from ancient times, and brought to Europe by caravan from the dry lake bed in Tibet where it was found. Extensive deposits of this type are, or have been, worked in California and Nevada. The crystals are loose, fully developed, and often quite large; single crystals to 6 or 7 in. (15 or 20 cm) long and as much as a pound (0.5 kg) in weight have been recorded. Many are natural, as at Searles Lake, California; better ones are formed in sumps during mining operations, as at Boron, California. It is used as a flux, an antiseptic, as a water softener--and in mineralogy for borax beads. Its ancient name, tincal, is now applied to the unpurified state of sodium borate (tincalconite).

Sodium borate. Poisoning occurs only in animals that eat relatively large amounts. Signs include diarrhea, prostration and convulsions.

For other uses, see Borax (disambiguation).

Borax
IUPAC name	Sodium tetraborate decahydrate
Identifiers
CAS number	[[http://www.commonchemistry.org/ChemicalDetail.aspx?ref=1330-43-4 (anhydrous) 1303-96-4 (decahydrate) 1330-43-4 (anhydrous) 1303-96-4 (decahydrate)]]
Properties
Molecular formula	Na2B4O7·10H2O or Na2[B4O5(OH)4]·8H2O
Molar mass	381.37
Appearance	white solid
Density	1.73 g/cm³ (solid)
Melting point	741 °C
Boiling point	1575 °C
Hazards
EU classification	not listed
NFPA 704	0 1 0
Flash point	Non-flammable
Related compounds
Other anions	Sodium aluminate; sodium gallate
Other cations	Potassium tetraborate
Related compounds	Boric acid, sodium perborate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references

Old steam tractor and Borax wagons, Death Valley

Borax, also known as sodium borate, sodium tetraborate, or disodium tetraborate, is an important boron compound, a mineral, and a salt of boric acid. It is usually a white powder consisting of soft colorless crystals that dissolve easily in water.

Borax has a wide variety of uses. It is a component of many detergents, cosmetics, and enamel glazes. It is also used to make buffer solutions in biochemistry, as a fire retardant, as an anti-fungal compound for fiberglass, as an insecticide, as a flux in metallurgy, and as a precursor for other boron compounds.

The term borax is used for a number of closely related minerals or chemical compounds that differ in their crystal water content, but usually refers to the decahydrate. Commercially sold borax is usually partially dehydrated.

The word borax is from Persian and originates in the Middle-Persian būrak.^[1]

Contents 1 Uses 1.1 Buffer 1.2 Co-complexing 1.3 Flux 1.4 Small-scale mining 1.5 Putty 1.6 Food additive 1.7 Other uses 2 Natural sources 3 Toxicity 4 Chemistry 5 See also 6 References 7 External links

Uses

Buffer

Sodium borate is used in biochemical and chemical laboratories to make buffers, e.g. for gel electrophoresis of DNA, such as TBE or the newer SB buffer or BBS (borate buffered saline) in coating procedures. Borate buffers (usually at pH 8) are also used as preferential equilibration solution in DMP-based crosslinking reactions.

Co-complexing

Borax as a source of borate has been used to take advantage of the co-complexing ability of borate with other agents in water to complex various substances. Borate and a suitable polymer bed are used to chromatograph non-glycosylated hemoglobin differentially from glycosylated hemoglobin (chiefly HbA1c), which is an indicator of long term hyperglycemia in diabetes mellitus. Borate and a proprietary synthetic amino acid, Deselex (from Henkel) have been used to complex water "hardness" cations to make a non-precipitating water "softener". Borate alone does not have a high affinity for "hardness" cations, although it has been used for that purpose.

Flux

A mixture of borax and ammonium chloride is used as a flux when welding iron and steel. It lowers the melting point of the unwanted iron oxide (scale), allowing it to run off. Borax is also used mixed with water as a flux when soldering jewelry metals such as gold or silver. It allows the molten solder to flow evenly over the joint in question. Borax is also a good flux for 'pre-tinning' tungsten with zinc - making the tungsten soft-solderable.^[2]

Small-scale mining

Borax is replacing mercury as the preferred method for extracting gold in small-scale mining facilities. The method is called the borax method and was first discovered in Sweden and used in the Philippines. ^[3]

Putty

When a borax-water solution is mixed with PVA glue (wood glue), a rubbery precipitate is formed which is the result of cross-linking in the polymer.^[4]

Food additive

Borax, given the E number E285, is used as a food additive in some countries but is banned in the United States. In consequence certain foods, such as caviar, produced for sale in the U.S. contain higher levels of salt to assist preservation.^[5] In China it was found to have been added to hand-pulled noodles (lamian).^{[citation needed]} In Indonesia it is a common, but forbidden, additive to such foods as noodles, meatballs and steamed rice. The country's Directorate of Consumer Protection warns of the risk of liver cancer with high consumption over a period of 5–10 years.^[6]

Other uses

• Component of detergents
• Ingredient in enamel glazes
• Component of glass, pottery, and ceramics
• Fire retardant
• Anti-fungal compound for fibreglass and cellulose insulation
• Insecticide to kill ants, cockroaches and fleas
• Precursor for sodium perborate monohydrate that is used in detergents, as well as for boric acid and other borates
• Tackifier ingredient in casein, starch and dextrin based adhesives
• Precursor for Boric acid, a tackifier ingredient in polyvinyl acetate, polyvinyl alcohol based adhesives
• Treatment for thrush in horses' hooves
• Used to make indelible ink for dip pens by dissolving shellac into heated borax
• Curing agent for snake skins
• Swimming pool buffering agent to control the pH
• Neutron absorber, used in nuclear reactors and spent fuel pools to control reactivity and to shut down a nuclear chain reaction
• In agriculture it can be used to correct boron deficient soils; however, it is required in small amounts. Excess can cause injury to plants.
• To Clean the brain cavity of a skull for mounting
• To colour fires a green tint^[7]
• Borax can be used as an additive in ceramic slips and glazes to improve fit on wet, greenware, and bisque.
• Borax was traditionally used to coat dry-cured meats such as hams to protect them from becoming fly-blown during further storage.

Natural sources

Borax "cottonball"

Borax occurs naturally in evaporite deposits produced by the repeated evaporation of seasonal lakes. The most commercially important deposits are found in Turkey and Boron, California and other locations in the Southwestern United States, the Atacama desert in Chile, and in Tibet and Romania. Borax can also be produced synthetically from other boron compounds.

Toxicity

Borax, sodium tetraborate decahydrate, is not acutely toxic. ^[8] Its LD₅₀ (median lethal dose) score is tested at 2.66 g/kg in rats. ^[9] This does not mean that it is safe, merely that a significant dose of the chemical is needed to cause severe symptoms or death. The median lethal dose for humans tends to differ for a given compound from that of rats. Simple exposure can cause respiratory and skin irritation. Ingestion may cause gastrointestinal distress including nausea, persistent vomiting, abdominal pain, and diarrhea. Effects on the vascular system and brain include headaches and lethargy, but are less frequent. "In severe poisonings, a beefy red skin rash affecting palms, soles, buttocks and scrotum has been described. With severe poisoning, erythematous and exfoliative rash, unconsciousness, respiratory depression, and renal failure." ^[10]

A reassessment of boric acid/borax by the United States Environmental Protection Agency Office of Pesticide Programs found potential developmental toxicity (especially effects on the testes).^[11] Boric acid solutions used as an eye wash or on abraded skin are known to be especially toxic to infants, especially after repeated use because of its slow elimination rate.^[12]

Chemistry

The structure of the anion [B₄O₅(OH)₄]²⁻ in borax

The term borax is often used for a number of closely related minerals or chemical compounds that differ in their crystal water content:

• Anhydrous borax (Na₂B₄O₇)
• Borax pentahydrate (Na₂B₄O₇·5H₂O)
• Borax decahydrate (Na₂B₄O₇·10H₂O)

Borax is generally described as Na₂B₄O₇·10H₂O. However, it is better formulated as Na₂[B₄O₅(OH)₄]·8H₂O, since borax contains the [B₄O₅(OH)₄]²⁻ ion. In this structure, there are two four-coordinate boron atoms (two BO₄ tetrahedra) and two three-coordinate boron atoms (two BO₃ triangles).

Borax is also easily converted to boric acid and other borates, which have many applications. If left exposed to dry air, it slowly loses its water of hydration and becomes the white and chalky mineral tincalconite (Na₂B₄O₇·5H₂O).

When borax is added to a flame, it produces a yellow green color.^[13] This property has been tried in amateur fireworks,^{[citation needed]} but borax in this use is not popular because its waters of hydration inhibit combustion of compositions and make it an inferior source of the boron which is responsible for most of the green color, and which is overwhelmed by the yellow contributed to the flame by sodium.

However, commercially available borax can be mixed with flammables such as methanol to give the characteristic green flame of boron when ignited, which then slowly gives way to the characteristic yellow-orange flame of the sodium.

See also

• Buffer solution
• Borax bead test
• Sodium borohydride
• Ulexite
• Twenty-Mule-Team Borax
• Francis Marion Smith
• John Veatch
• Boric acid
• List of cleaning agents

References

1. ^ http://www.thefreedictionary.com/borax
2. ^ Dodd, J.G. (1966), "Soft soldering to tungsten wire", Am. J. Phys 34 (10): p. xvi, doi:10.1119/1.1972398 
3. ^ "The borax method". Borax replacing mercury in small-scale mining. The Geological Survey of Denmark and Greenland (GEUS). http://www.geus.dk/program-areas/common/int_ssm_fact_sheet_07.pdf. Retrieved on 2008-08-02. 
4. ^ Parratore, Phil. Wacky Science: A Cookbook for Elementary Teachers. Dubuque, IA: Kendall Hunt. p. 26. ISBN 0787227412. 
5. ^ "Caviar glossary". The Caviar Guide a gourmet review of caviars & fish roe. Hanson Ltd, Geneva, Switzerland. http://www.hanscon.ch/caviar_website/glossary.htm. Retrieved on 2008-07-07. 
6. ^ Staff writer (2006). "Watch Out For The Food We Consume" (in English). Directorate of Consumer Protection, Jakarta, Indonesia. http://pkditjenpdn.depdag.go.id/English/index.php?page=infodtl&InfoID=8&dtl=1. Retrieved on 2009-02-10. 
7. ^ http://chemistry.about.com/cs/howtos/a/aa052703a.htm
8. ^ Borax - toxicity, ecological toxicity and regulatory information
9. ^ Mountain Fresh Dial Bar Soap
10. ^ Borax - toxicity, ecological toxicity and regulatory information
11. ^ Report of the Food Quality Protection Act (FQPA) Tolerance Reassessment Eligibility Decision (TRED) for Boric Acid/Sodium Borate Salts
12. ^ Goodman and Gillman's: The Pharmacological Basis of Therapeutics, 6th edition, chapter on Antiseptics and Disinfectants, page 971
13. ^ Staff. "Creating Flame Colors". The Science Company. http://www.sciencecompany.com/sci-exper/flamecolors.htm. Retrieved on November 30 2008. 

External links

• International Chemical Safety Card 0567
• International Chemical Safety Card 1229 (fused borax)
• National Pollutant Inventory - Boron and compounds
• NIOSH Pocket Guide to Chemical Hazards
• Sodium Borate in sefsc.noaa.gov

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
1.
n. - natriumtetraborat, boraks, E285

2.
n. - tingeltangel, billigt skrammel, billigt juks

Nederlands (Dutch)
goedkope troep, borax

Français (French)
1.
n. - borax

2.
n. - camelote, bric-à-brac

Deutsch (German)
1.
n. - (chem.) Borax

2.
n. - billige Ware, geschmacklose Einrichtungsgegenstände

Ελληνική (Greek)
n. - (χημ.) βόρακας, τετραβορικό νάτριο

Italiano (Italian)
borace

Português (Portuguese)
n. - bórax (m) (Quím.), borato de sódio (m) (Quím.)

Русский (Russian)
бура

Español (Spanish)
1.
n. - objetos baratos, de baja calidad y llamativos

2.
n. - bórax, atíncar

Svenska (Swedish)
n. - borax

中文（简体）(Chinese (Simplified))
1. 硼砂, 月石

2. 便宜而蹩脚的商品

中文（繁體）(Chinese (Traditional))
1.
n. - 硼砂, 月石

2.
n. - 便宜而蹩腳的商品

한국어 (Korean)
1.
n. - 붕사

2.
n. - 싸구려 상품[가구], 거짓말

日本語 (Japanese)
n. - ホウ砂

العربيه (Arabic)
‏(الاسم) مسحوق أبيض للتعقيم‏

עברית (Hebrew)
n. - ‮מלח נתרן עם חומצת בור המשמש לריתוך, לחיטוי ובייצור זכוכית וחרסינה, תרכובת בור, בוראקס‬
n. - ‮סחורה זולה בעיקר ריהוט זול‬

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