Crystal Chemistry and X-ray Diffraction Patterns for Co(NixZn1-x)Nb4O12 (x=0.2, 0.4, 0.6, 0.8)
Winnie K. Wong-Ng, Guangyao Liu, James A. Kaduk
X-ray reference powder patterns and structures have been determined for a series of titanium-, zinc-, and cobalt-containing niobates, Co(NixZn1-x)Nb4O12 (x=0.2, 0.4, 0.6, 0.8). The Co(NixZn1-x)Nb4O12 series crystallize in the space group of Pbcn, which is of the disordered columbite structure type (Alpha-PbO2). The lattice parameters range from a = 14.11190(13) Å to 14.1569(3) Å, b = 5.69965(6) Å to 5.71209(13)Å, c = 5.03332(5)Å to 5.03673(11)Å, and V = 404.844(8) Å3 to V = 407.296(17) Å3 from x = 0.8 to x = 0.2, respectively. Co(NixZn1-x)Nb4O12 contains double zig-zag chains of NbO6 octahedra and single chain of (Ni,Zn,Co)O6 octahedra run parallel to the bc-plane. Within the same chain the NbO6 octahedra share edges, while the adjacent NbO6 chains are joined to each other through common oxygen corners. These double NbO6 chains are further linked together along the  direction through another (Co,Ni,Zn)O6 units, via common oxygen corners. The edge-sharing (Co,Ni,Zn)O6 also form zig-zag chains along the c-axis. Powder X-ray diffraction patterns of this series of compounds have been submitted to be included in the Powder Diffraction File (PDF).