CaO5SiTi
Speer, J. A.Gibbs, G. V.
American Mineralogist (1976) 61, 238-247
a=7.069Å b=8.722Å c=6.566Å
α=90° β=113.86° γ=90°
HfO4Si
Speer, J. A.Cooper, B. J.
American Mineralogist (1982) 67, 804-808
a=6.5725Å b=6.5725Å c=5.9632Å
α=90° β=90° γ=90°