Hydrothermal syntheses and crystal structures of molybdenum tellurites

Abstract

Hydrothermal reactions of MoO3 and TeO2 in acidic conditions resulted three new molybdenum tellurites, MoTeO5 (1), β-MoTe2O7 (2), and MoTe4O11·KCl (3). Within the structures of three compounds, all Mo(VI) atoms adopt distorted MoO6 octahedra in a 2 ​+ ​2 + 2 mode with two short, two normal, and two long Mo–O bonds, while Te(IV) atoms are coordinated by three, four and five oxygen atoms and result TeO3 trigonal pyramid, TeO4 seesaw, and TeO5 square pyramid polyhedra with Te–O bond distance cut off at 2.5 ​Å. Compound 1 adopts a one-dimensional chain structure in which Mo2O10 dimers, formed by edge-sharing two MoO6 octahedra, are connected by TeO3 polyhedra in a corner-sharing mode. Compound 2 also exhibits a one-dimensional chain structure in which TeO3 and TeO5 polyhedra are joined together by corner-sharing and results a new [Te4O10]4- chain. MoO6 octahedra are incorporated in the tellurite chain by corner-sharing two TeO5 and two TeO3 polyhdedra and edge-sharing another TeO5. Compound 3 adopts a two-dimensional sheet structure. Within the structure, a new hexagon patterned [Te4O9]2- chain is formed by corner-sharing TeO4 and TeO3 polyhedra. These Te chains are connected by MoO6 polyhedra and extend in yz plane. Crystallographic data: compound 1, monoclinic, space group P21/c, a ​= ​4.7106 (3) Å, b ​= ​13.5827 (11) Å, c ​= ​6.0962 (5) Å, β ​= ​93.898 (3)°, V ​= ​389.15 (5) Å3, Z ​= ​4; compound 2, orthorhombic, space group Pna21, a ​= ​17.5632 (5) Å, b ​= ​4.9107 (2) Å, c ​= ​12.9518 (4) Å, V ​= ​1117.06 (7) Å3, Z ​= ​8; compound 3, orthorhombic, space group Pbcm, a ​= ​6.0017 (3) Å, b ​= ​11.6302 (6) Å, c ​= ​16.6773 (5) Å, V ​= ​1164.09 (10) Å3, Z ​= ​4.