| Section8 = Chembox Related | OtherAnions = Sodium aluminate ; sodium gallate | OtherCations = Potassium tetraborate | OtherCpds = Boric acid , sodium perborate Borax , also known as sodium borate , sodium tetraborate , or disodium tetraborate , is an important boron compound, a mineral , and a salt (chemistry)|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 detergent s, cosmetics , and vitreous enamel|enamel glazes. It is also used to make buffer solution s in biochemistry , as a fire retardant , as an anti-fungal compound for glass wool|fiberglass , as a flux (metallurgy)|flux in metallurgy , neutron-capture shields for radioactive sources, a texturing agent in cooking, 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 Water of crystallization|crystal water content, but usually refers to the wikt:decahydrate|decahydrate . Commercially sold borax is usually partially dehydrated.
The word wikt:borax|borax:???? is Arabic language|Arabic – the Arabic is said to be from the Persian burah , a word that may have meant potassium nitrate or another fluxing agent. Another name for borax is tincal, from Sanskrit language|Sanskrit .cite web|url= http://www.azom.com/article.aspx? ArticleID=2588|title=Borax ( Na2B4O7. 10H2O ) – Sodium Borate – Occurrence, Discovery and Applications|work=Amoz.com
Borax was first discovered in dry lake beds in Tibet and was imported via the Silk Road to Arabia. Borax first came into common use in the late 19th century when Francis Marion Smith 's Pacific Coast Borax Company began to market and popularize a large variety of applications under the famous 20 Mule Team Borax trademark , named for the method by which borax was originally hauled out of the California and Nevada deserts in large enough quantities to make it cheap and commonly available."American Borax Production" Scientific American September 22, 1877Hildebrand, G. H. (1982) "Borax Pioneer: Francis Marion Smith." San Diego: Howell-North Books. p. 267 ISBN 0-8310-7148-6
Uses
Household products
Borax is used in various household laundry and cleaning products,HPD|136 including the " 20 Mule Team Borax " laundry booster and " Boraxo " powdered hand soap. However, despite its name, "Borateem" laundry bleach no longer contains borax or other boron compounds. Borax is also present in some tooth bleaching formulas.Cite book| author = Hammond, C. R.|title = The Elements, in Handbook of Chemistry and Physics 81st edition| publisher =CRC press| isbn = 0-8493-0485-7| year = 2004
Buffer
Sodium borate is used in biochemistry|biochemical and chemistry|chemical laboratories to make buffer solution|buffers , e.g. for gel electrophoresis of DNA , such as TBE buffer|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 form complex ions with 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- Precipitation (chemistry)|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 (metallurgy)|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 metal s 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.Cite journal | first = J.G. | last = Dodd | doi = 10.1119/1.1972398 | journal = Am. J. Phys | volume = 34 | issue = 10 | pages = xvi | year = 1966 | title = Soft soldering to tungsten wire | accessdate = 2008-05-01
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 is used in the Philippines.cite web|url= http://www.geus.dk/program-areas/common/int_ssm_fact_sheet_07.pdf|title= The borax method|work=Borax replacing mercury in small-scale mining|publisher=The Geological Survey of Denmark and Greenland (GEUS)|accessdate=2008-08-02
Putty
main|Flubber (material)A rubbery polymer sometimes called flubber , gluep or glurch can be made by cross linking polyvinyl acetate with a borax. Making flubber from polyvinyl acetate based glue s, such as Elmer's Products, Inc.|Elmer's Glue , and borax is a common elementary education experiment.cite book|last=Parratore|first=Phil |title=Wacky Science: A Cookbook for Elementary Teachers|publisher=Kendall Hunt|location=Dubuque, IA|page=26|isbn=0-7872-2741-2
Food additive
Borax, given the E number E285 , is used as a food additive in some countries, but is banned in the US. As a consequence, certain foods, such as caviar , produced for sale in the US contain higher levels of salt to assist preservation.cite web|url= http://www.hanscon.ch/caviar_website/glossary.htm|title= Caviar glossary|work=The Caviar Guide a gourmet review of caviars & fish roe |publisher=Hanson Ltd, Geneva, Switzerland|accessdate=2008-07-07 Its use as a cooking ingredient is to add a firm rubbery texture to the food, or as a preservative. In oriental cooking it is mostly used for its texturing properties. In Asia , Borax (zh|c=??|p=péng? sha?) or (zh|c=??|p=yuè shí?) was found to have been added to some Chinese foods like hand-pulled noodles lamian and some rice noodles like Shahe fen , Kway Teow , and Chee Cheong Fun recipes. http://chowhound.chow.com/topics/279712 Chinese Ingredients: Borax Powder, Sep 11, 2005, Chow Hound, Home Cooking. Chowhound.chow.com. Retrieved on 2012-02-17. In Indonesia it is a common, but forbidden, additive to such foods as noodles, bakso (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.cite web|url= http://web.archive.org/web/20081228204459/ http://pkditjenpdn.depdag.go.id/English/index.php? page=infodtl& InfoID=8& dtl=1|title=Watch Out For The Food We Consume|last=Staff writer|year=2006|publisher=Directorate of Consumer Protection, Jakarta, Indonesia|accessdate=2009-02-10
Other uses
Ingredient in vitreous enamel|enamel glazes
Component of glass , pottery , and ceramic s
Borax can be used as an additive in ceramic slips and ceramic glaze|glazes to improve fit on wet, greenware, and bisque (pottery)|bisque .
Fire retardant
Anti-fungal compound for glass wool|fiberglass and cellulose insulation
Moth proofing 10% solution for woolSarah Jenkinson and Nick Harrison http://www.cat.org.uk/news/news_release.tmpl? command=search& db=news.db& eqSKUdatarq=10340 Sheep's wool insulation in action! Centre for Alternative Technology (2000)
Anti-fungal foot soak
Precursor for sodium perborate|sodium perborate monohydrate that is used in detergent s, 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
Fluoride detoxification
Treatment for thrush (horse)|thrush in horse s' Horse hoof|hooves
Used to make indelible ink for dip pen s by dissolving shellac into heated borax
Curing agent for snake skins
Curing agent for salmon eggs, for use in sport fishing for salmon
Swimming pool buffering agent to control the pH
Neutron absorber , used in boiling water reactor|nuclear reactor s and spent fuel pools to control reactivity and to shut down a nuclear chain reaction
As a micronutrient fertilizer to correct boron-deficient soils. http://nature.berkeley.edu/classes/eps2//wisc/borax.html Borax at UC Berkeley
To clean the brain cavity of a skull for mounting
To color fires with a green tint http://chemistry.about.com/cs/howtos/a/aa052703a.htm How To Color Fire. chemistry.about.com
Was traditionally used to coat dry-cured meats such as hams to protect them from becoming fly-blown during further storage.
Is found in some commercial vitamin supplement s
For stopping car radiator and engine block leaks http://www.a1motorstores.co.uk/shop-manager-info/cosshh/Holts_RadWeld_125ml.pdf Radweld safety data sheet Retrieved 19-02-2010
As an important component in Slime (toy)|Slime http://chemistry.about.com/od/chemistryactivities/ss/slimerecipe.htm Step-By-Step Slime Instructions. Chemistry.about.com. Retrieved on 2012-02-17.
Is used by the modern Blacksmith in the process of Forge Welding . (Different from fabrication Gas or Electric style welding )
Natural sources
Borax occurs naturally in evaporite deposits produced by the repeated evaporation of seasonal lakes . The most commercially important deposits are found in Turkey ; Boron, California ; and Searles Lake , California . Also, has been found at many other locations in the Southwestern United States , the Atacama desert in Chile , newly-discovered deposits in Bolivia , and in Tibet and Romania . Borax can also be produced synthetically from other boron compounds. Naturally occurring Borax, (known by the trade name Rasorite – 46 in USA and many other countries) is refined by a process of re-crystallization.cite journal|last=Wizniak|first=Jaime|date=July 2005|title=Borax, Boric Acid, and Boron—From exotic to commodity|journal=Indian Journal of Chemical Technology|publisher=Council of Scientific and Industrial Research|location=New Delhi|volume=12|issue=4|issn=0975-0991|url= http://nopr.niscair.res.in/bitstream/123456789/8663/1/IJCT%2012(4)%20488-500.pdf
Toxicity
Borax, sodium tetraborate decahydrate, is not acutely toxic. http://pesticideinfo.org/Detail_Chemical.jsp? Rec_Id=PC34355#Toxicity Borax – toxicity, ecological toxicity and regulatory information. Pesticideinfo.org. Retrieved on 2012-02-17. Its LD50 (median lethal dose) score is tested at 2.66 g/kg in rats: http://www2.prosarcorp.com/files_F/doc_0027/32C37.pdf Mountain Fresh Dial Bar Soap. (PDF) . Retrieved on 2012-02-17. a significant dose of the chemical is needed to cause severe symptoms or death. The lethal dose is not necessarily the same for humans.
Sufficient exposure to borax dust 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 Human brain|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 Exfoliation (cosmetology)|exfoliative rash, unconsciousness, respiratory depression, and renal failure. http://pesticideinfo.org/Detail_Chemical.jsp? Rec_Id=PC34355 Borax – toxicity, ecological toxicity and regulatory information. Pesticideinfo.org. Retrieved on 2012-02-17.
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 ). http://www.epa.gov/oppsrrd1/REDs/boric_acid_tred.pdf Report of the Food Quality Protection Act (FQPA) Tolerance Reassessment Eligibility Decision (TRED) for Boric Acid/Sodium Borate Salts. (PDF) . Retrieved on 2012-02-17. Boric acid solutions used as an eye wash or on abraded skin are known to be particularly toxic to infants, especially after repeated use, because of the slow elimination rate.''Goodman and Gillman's: The Pharmacological Basis of Therapeutics, 6th edition , chapter on Antiseptics and Disinfectants, p. 971
Borax was added to the Substance of very high concern|Substance of Very High Concern (SVHC) candidate list on 16 December 2010. The SVHC candidlate list is part of the European Union|EU Regulations on the Registration, Evaluation, Authorisation and Restriction of Chemicals 2006 (REACH), and the addition was based on the revised classification of Borax as toxic for reproduction category 1B under the CLP Regulation 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". http://web.archive.org/web/20110725113454/ http://echa.europa.eu/doc/candidate_list/svhc_supdoc_disodium_tetraborate_anhydrous_publication.pdf 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 9 June 2010. Echa.europa.eu. Retrieved on 2012-02-17.
Chemistry
The term borax is often used for a number of closely related minerals or chemical compounds that differ in their Water of crystallization|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 Na2B4O5(OH)4·8H2O, since borax contains the B4O5(OH)42- 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. Its reaction with hydrochloric acid to form boric acid is:
The "decahydrate" is sufficiently stable to find use as a primary standard for acid base titrimetry .VogelQuantitative p. 316.
When borax is added to a flame, it produces a yellow green color.cite web|url= http://www.sciencecompany.com/sci-exper/flamecolors.htm|title=Creating Flame Colors|last=Staff|publisher=The Science Company|accessdate=November 30, 2008 This property has been tried in amateur fireworks,Citation needed|date=December 2008 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 that is responsible for most of the green color, and that 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.
