Materials Data on Mg2TcO4 by Materials Project

Abstract

Mg2TcO4 is Spinel-like structured and crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with six equivalent MgO6 octahedra and corners with six equivalent TcO6 octahedra. The corner-sharing octahedra tilt angles range from 57–59°. There are two shorter (1.99 Å) and two longer (2.04 Å) Mg–O bond lengths. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six equivalent MgO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four equivalent TcO6 octahedra. There are four shorter (2.09 Å) and two longer (2.13 Å) Mg–O bond lengths. Tc4+ is bonded to six O2- atoms to form TcO6 octahedra that share corners with six equivalent MgO4 tetrahedra, edges with two equivalent TcO6 octahedra, and edges with four equivalent MgO6 octahedra. There are two shorter (2.03 Å) and four longer (2.07 Å) Tc–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two Mg2+ and two equivalent Tc4+ atoms to form a mixture of distorted edge and corner-sharing OMg2Tc2 trigonal pyramids. In the second O2- site, O2- is bonded to three Mg2+ and one Tc4+ atom to form a mixture of distorted edge and corner-sharing OMg3Tc trigonal pyramids.