Boron

Name:
Boron
Detailed information:

M Formula:	B
Properties:
Black, hard solid; brown, amorphous powder; crystals. D 2.45, mp 2300C, Mohs hardness 9.3. Highly reactive. Soluble in concentrated nitric and sulfuric acids; insoluble in water,alcohol, and ether. High neutron absorption capacity. Amphoteric. A plant micronutrient.
Source:
Borax, kernite, colemanite, ulexite.
Derivation:
(1) By heating boric oxide with powdered magnesium or aluminum; (2) by vapor-phase reduction of boron trichloride with hydrogen over hot filaments (80–2000C); (3) by electrolysisof fused salts.
Available forms:
Filament, powder, whiskers, single crystals.
Grade:
Technical (90–92%), 99% pure, high-purity crystals.
Hazard:
Dust ignites spontaneously in air; severe fire and explosion hazard. Reacts exothermally with metals above 900C; explodes with hydrogen iodide.
Use:
Special-purpose alloys, cementation of iron, neutron absorber in reactor controls, oxygen scavenger for copper and other metals, fibers and filaments in composites with metals or ceramics,semiconductors, boron-coated tungsten wires, rocket propellant mixtures, high-temperature brazing alloys.

See Boron Alloy; Boron Fiber; Boron-10.