Boraces

Borax is a hydrated sodium borate mineral (Na2B4O7 10H2O, density 1.715). It crystallizes in the monoclinic system, usually in short prismatic crystals. Borax ranges from colorless through gray, blue to greenish and has a vitreous to resinous luster of translucent to opaque character. Borax is a product of evaporation from shallow lakes. 

Borax is used in antiseptics and medicines, as a flux in smelting, soldering, and welding operations as a deoxidizer in nonferrous metals as a neutron absorber for atomic energy shields in rocket fuels and as extremely hard, abrasive boron carbide (harder than corundum). 

Sodium borate decahydrate sodium tetraborate decahydrate sodium biborate sodium pyroborate 

Borax is used in laundry detergents and bleaches. It releases hydrogen peroxide when it reacts with water. Hydrogen peroxide acts as a bleach, and its action is aided by the alkaline solution also produced by the reaction. 

Borax is a good buffer, helping to stabilize the acidity or alkalinity of a solution. 

The boron (along with the oxygen and salt) in a borax solution helps to disinfect by killing bacteria and fungi. 

---

Raschig process See hydrazine, rasorite See kernite, borax. 

Boron does not occur free in nature in minerals, it occurs as borates, for example, kernite. Na2B407.4H2O. and borax. Na2B407. IOH2O there are extensive deposits of these in the USA. Boron can be obtained by heating boron trioxide with magnesium ... 

Boron trioxide is not particularly soluble in water but it slowly dissolves to form both dioxo(HB02)(meta) and trioxo(H3B03) (ortho) boric acids. It is a dimorphous oxide and exists as either a glassy or a crystalline solid. Boron trioxide is an acidic oxide and combines with metal oxides and hydroxides to form borates, some of which have characteristic colours—a fact utilised in analysis as the "borax bead test , cf alumina p. 150. Boric acid. H3BO3. properly called trioxoboric acid, may be prepared by adding excess hydrochloric or sulphuric acid to a hot saturated solution of borax, sodium heptaoxotetraborate, Na2B407, when the only moderately soluble boric acid separates as white flaky crystals on cooling. Boric acid is a very weak monobasic acid it is, in fact, a Lewis acid since its acidity is due to an initial acceptance of a lone pair of electrons from water rather than direct proton donation as in the case of Lowry-Bronsted acids, i.e. 

Borax is used in the production of pyrex glass, ceramics, as a flux in soldering and welding, and in laundering to impart a glaze to linen. 

Prepare a solution of casein as follows. Weigh out 15 g. of casein into a dry 500 ml. conical flask and add about 150 ml. of water. Dissolve 1 5 g. of anhydrous sodium carbonate and i 5 g, of borax in about 20 ml. of hot water and add this solution to the casein. Warm until a solution is obtained, filter if necessary, and make up to a total volume of about 250 ml. with water. Add a few drops of toluene (to prevent putrefaction) and shake the solution. 

Important sources of boron are ore rasorite (kernite) and tincal (borax ore). Both of these ores are found in the Mojave Desert. Tincal is the most important source of boron from the Mojave. Extensive borax deposits are also found in Turkey. 

Boric acid is also an important boron compound with major markets in textile products. Use of borax as a mild antiseptic is minor in terms of dollars and tons. Boron compounds are also extensively used in the manufacture of borosilicate glasses. Other boron compounds show promise in treating arthritis. 

Jeweler s borax, see Sodium tetraborate 10-water Jeweler s rouge, see Iron(III) oxide... 

To prepare the standard pH buffer solutions recommended by the National Bureau of Standards (U.S.), the indicated weights of the pure materials in Table 8.15 should be dissolved in water of specific conductivity not greater than 5 micromhos. The tartrate, phthalate, and phosphates can be dried for 2 h at 100°C before use. Potassium tetroxalate and calcium hydroxide need not be dried. Fresh-looking crystals of borax should be used. Before use, excess solid potassium hydrogen tartrate and calcium hydroxide must be removed. Buffer solutions pH 6 or above should be stored in plastic containers and should be protected from carbon doxide with soda-lime traps. The solutions should be replaced within 2 to 3 weeks, or sooner if formation of mold is noticed. A crystal of thymol may be added as a preservative. 

NaOAc, Acetic KH2PO4 Borax, KH2PO4, Borax... 

Borax stability Boraz anaphthalene Borazine [6569-51-3] Boraz ines Borazon... 

Other salts, most notably borax, are also recovered from the lake. 

Boron. The principal materials used are borax [1303-96-4] sodium pentaborate, sodium tetraborate, partially dehydrated borates, boric acid [10043-35-3] and boron frits. Soil appHcation rates of boron for vegetable crops and alfalfa are usually in the range of 0.5—3 kg/hm. Lower rates are used for more sensitive crops. Both soil and foHar appHcation are practiced but soil appHcations remain effective longer. Boron toxicity is not often observed in field appHcations (see Boron compounds). 

---