Si2U
Sasa, Y.Uda, M.
Journal of Solid State Chemistry (1976) 18, 63-68
a=3.922Å b=3.922Å c=14.154Å
α=90° β=90° γ=90°
N3U2
Sasa, Y.Atoda, T.
Journal of the American Ceramic Society (1970) 53, 102-105
a=3.696Å b=3.696Å c=5.84Å
α=90° β=90° γ=120°