Nomenclature
CAS number: 1330-43-4
Boron sodium oxide (B
4Na
2O
7); anhydrous borax; borax glass; fused borax; sodium biborate; sodium pyroborate; sodium tetraborate.
B
4Na
2O
7; mol wt 201.22.
B 21.49%, Na 22.85%, O 55.66%.
Na
2B
4O
7.
Description and references
Toxicity: H. F. Smyth et al., Am. Ind. Hyg. Assoc. J. 30, 470
(1969). Review of toxicology and human exposure: Toxicological Profile for Boron (PB93-110674,
1992) 110 pp.
Properties
Powder or glass-like plates becoming opaque on
exposure to air. Slowly sol in water.Derivative
Decahydrate.
Nomenclature
CAS number: 1303-96-4
Borax; Jaikin (Basotherm).
B
4Na
2O
7.10H
2O; mol wt 381.37.
B 11.34%, Na 12.06%, O 71.32%, H 5.29%.
Properties
Hard odorless crystals, granules or cryst powder;
efflorescent in dry air, the crystal often being coated with white
powder. d 1.73. Melts
when rapidly heated at 75°; at 100° loses 5H2O; at 150°
loses 9H2O; becomes anhydr at 320°. One gram dissolves
in 16 ml water, 0.6 ml boiling water, about 1 ml glycerol. Insol
in alcohol. The aq soln is alkaline to litmus and phenolphthalein.
pH about 9.5. Borax dissolves many metallic oxides when fused with
them. LD50 orally in rats: 5.66 g/kg (Smyth).Caution
Potential symptoms of overexposure
are irritation of eyes, skin, upper respiratory system; dermatitis;
epistaxis; cough, dyspnea. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH
97-140, 1997) p 30.Use
Soldering metals; manuf glazes and enamels; tanning;
in cleaning compds; artificially aging wood; as preservative, either
alone or with other antiseptics against wood fungus; fireproofing
fabrics and wood; curing and preserving skins; in cockroach control.
In buffers; as a complexing or masking agent in analytical chemistry.
Pharmaceutic aid (alkalizer).