Crystal structures of the solid solutions Na3Zn0.912Cd0.088B5O10 and Na3Zn0.845Mg0.155B5O10

Abstract

Two new pentaborates, trisodium zinc cadmium pentaborate, Na3Zn0.912Cd0.088B5O10, and trisodium zinc magnesium pentaborate, Na3Zn0.845Mg0.155B5O10, 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 orthorhombic form of the parent compound Na3ZnB5O10 (space group type Pbca, Z = 8) and contain the double ring [B5O10]5− anion composed of one BO4 tetrahedron and four BO3 triangles as the basic structural motif. The anions are bridged by tetrahedrally coordinated and occupationally disordered M2+ (M = Zn/Cd, Zn/Mg) cations via common O atoms to form [MB5O10]n3n− layers. The intralayer intersecting channels and the interlayer voids are occupied by Na+ cations to balance the charge.

Keywords

• crystal structure
• Na3ZnB5O10
• solid solution
• borate
• isotypism