SYNTHESIS AND CRYSTAL-STRUCTURE OF NEW COMPLEX OXIDES K10M2+MO7O27 (M2+ = MG, MN, CO)

New compounds, K10M2+Mo7O27(M2+ = Mg, Mn, Co), have been synthesized a nd characterized. the compounds have an original structure, asa establ ished for the first two phases (orthorhombic, space group Pnm2(1), Z = 2, a = 18.353 and 18.402, b = 7.889 and 7.931, c = 10.566 and 10.604 Angstrom, R = 0.0345 and 0.0609, respectively). A specific feature of the structure is isolated clusters consisting of face-sharing MoO6 and M2+O6 octahedra, each of the latter having six MoO4 tetrahedra attach ed to it by vertices. The general pseudohexagonal motif of the structu re of the phases is similar to that of glaserites.