B4Na2O11
Cooper, W. F.Larsen, F. K.Coppens, P.Giese, R. F.
American Mineralogist (1973) 58, 21-31
a=7.0172Å b=9.1582Å c=15.6774Å
α=90° β=108.861° γ=90°
B4H8Na2O11