Nomenclature
CAS number: 10043-11-5
BN; mol wt 24.82.
B 43.56%, N 56.43%.
Description and references
Prepd by igniting compds of boron with compds
of nitrogen: Taylor, US 2855316 (1958 to Carborundum Co.). Reviews: Giardini, Bur. Mines Inf. Circ. No. 7664, 13 pp (1953); K. Niedenzu, J. W. Dawson, Boron-Nitrogen Compounds (Academic Press,
New York, 1965) pp 147-153.
Properties
Crystals with hexagonal, graphite lattice is most
common form. Borazon, cubic crystalline modification, is probably the hardest
substance known. There exists also an amorphous modification. mp 3000°. Begins to
sublime at a temp slightly below 3000°. Begins to dissociate in vacuo at about 2700°. The chemical behavior of BN is dependent
on the method of prepn. Not attacked by mineral acids, water; in
general resistant to chemical attack. Hot concd alkali cleaves boron-nitrogen
bond. Oxidation in air begins above 1200°. See Niedenzu,
Dawson, loc. cit.Use
Manuf of alloys; in semiconductors, nuclear reactors,
lubricants.