He
Schuch, A. F.Grilly, E. R.Mills, R. L.
Physical Review (1958) 110, 775-775
a=4.01Å b=4.01Å c=4.01Å
α=90° β=90° γ=90°
a=3.46Å b=3.46Å c=5.60Å
α=90° β=90° γ=120°