Allotropes of Boron
All allotropes of boron have very high melting points, from 2,200-2,300'C.
Amorphous Boron
[ B ]
An amorphous brown powder with a density of 2.350 g/cm
3
.
alpha-rhombohedral Boron
[ B
12
]
Clear red crystalline structure with a density of 2.46 g/cm
3
.
beta-rhombohedral Boron
[ B
12
]
An allotrope consisting of black crystals with a metallic appearance. Density is 2.31 g/cm
3
.
The most thermodynamically stable allotrope.
beta-tetragonal Boron
[ B
12
]
Black crystalline structure.
See Also
Allotrope
.