Boron
Crystal structure of boron allotropes
α-B
rP12
low-T moderate-P
β-B
rP105-108
low-P
γ-B
oP28
high-P
T-50 boron
tP50
moderate-P before melting
T-192 boron
tP192
moderate-P before melting
* See phase diagram on
Wikipedia
References