Garrelsite

B₇Ba₃H₄NaO₂₀Si₂

Ghose, S.Wan, C.Ulbrich, H. H.

Acta Crystallographica, Section B (1976) 32, 824-832

a=14.639Å   b=8.466Å   c=13.438Å

α=90°   β=114.21°   γ=90°