THE STRUCTURE OF NA6ZN3(ASO4)4.3H2O AND ITS RELATIONSHIP TO THE GARNET AND OTHER IA3D-DERIVED STRUCTURES
IE GREY, IC MADSEN, DJ JONES, PW SMITH
JOURNAL OF SOLID STATE CHEMISTRY | ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS | Published : 1989
The hydrated sodium zinc arsenate, Na6Zn3(AsO4)4 · 3H2O, has cubic symmetry, space group P213, a = 12.243(3) Å, Z = 4. The structure was refined to wR(F2) = 0.028 using 548 independent reflections from a microtwinned crystal. Both zinc and arsenic atoms are tetrahedrally coordinated. The ZnO4 tetrahedra share all vertices with the basal vertices of the AsO4 tetrahedra to give a 3-D framework that is closely related to the [B7O12]3- framework of corner-linked BO4 and BO3 in boracite. The sodium atoms (CN = 6) and water molecules occupy  channels in the framework. The structural relationships with the garnet structure and related Ia3d-derived structures are discussed. © 1989.