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 and characterized. The compounds have an original structure, as established for the first two phases (orthorhombic, space group Pnm21, Z = 2, a = 18353 and 18.402, b = 7.889 and 7.931, c = 10.566 and 10.604 a, 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 attached to it by vertices. The general pseudohexagonal motif of the structure of the phases is similar to that of glaserites.