Al2H4O9Si2
Dera, P.Prewitt, C. T.Japel, S.Bish, D. L.Johnston, C. T.
American Mineralogist (2003) 88, 1428-1435
a=5.161Å b=8.960Å c=14.459Å
α=90° β=96.77° γ=90°
a=5.082Å b=8.757Å c=13.771Å
α=90° β=89.60° γ=90°