Abstract
Two new penta-borates, tris-odium zinc cadmium penta-borate, Na(3)Zn(0.912)Cd(0.088)B(5)O(10), and tris-odium zinc magnesium penta-borate, Na(3)Zn(0.845)Mg(0.155)B(5)O(10), have been synthesized by high-temperature solution reactions at 1023 K. Their crystal structures were determined by single-crystal X-ray diffraction. Both solid solutions crystallize in the ortho-rhom-bic form of the parent compound Na(3)ZnB(5)O(10) (space group type Pbca, Z = 8) and contain the double ring [B(5)O(10)](5-) anion composed of one BO(4) tetra-hedron and four BO(3) triangles as the basic structural motif. The anions are bridged by tetra-hedrally coordinated and occupationally disordered M(2+) (M = Zn/Cd, Zn/Mg) cations via common O atoms to form [MB(5)O(10)] (n)(3n-) layers. The intra-layer inter-secting channels and the inter-layer voids are occupied by Na(+) cations to balance the charge.