Orthorhombic, space group Pnma with a = 10.132, b = 12.537 and c = 7.775Aa (all + or -0.001Aa). There are four formula units in the unit cell. The two types of octahedra share an edge and/or corners among themselves. The sulfate tetrahedron shares corners with both types of octahedra and these three units form crude sheets centered about the mirror planes. The sheets are jointed by the boron tetrahedra into a three-dimensional structure.--Modified journal abstract.

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