DOE OSTI2020
KCo2(MoO5)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. K1+ is bonded to six O2- atoms to form distorted KO6 octahedra that share corners with four equivalent CoO6 octahedra and corners with six equivalent MoO4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. There are four shorter (2.79 Å) and two longer (3.03 Å) K–O bond lengths. Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with three equivalent KO6 octahedra and corners with four equivalent CoO6 octahedra. The corner-sharing octahedra tilt angles range from 43–70°. There are a spread of Mo–O bond distances ranging from 1.74–1.86 Å. Co+3.50+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent KO6 octahedra, corners with four equivalent MoO4 tetrahedra, and edges with two equivalent CoO6 octahedra. The corner-sharing octahedral tilt angles are 59°. There are a spread of Co–O bond distances ranging from 1.79–2.17 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Co+3.50+ atoms. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one K1+ and one Mo6+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one K1+, one Mo6+, and one Co+3.50+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Mo6+ and two equivalent Co+3.50+ atoms.