AM_Bertrandite Formula: Si2 Be4 H2 O9 Name: Bertrandite Unit cell: 8.7135 15.268 4.5683 90.0 90.0 90.0 , V=607.76 Space group: CMC21 (36)

Downs J W , Ross F K , American Mineralogist , 72 (1987) p.979-983, Neutron-diffraction study of bertrandite, Note: O2y has been corrected