DOI: 10.17188/1654048
title: Materials Data on KMg6SbO8 by Materials Project

description: KMg6SbO8 is Caswellsilverite-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. K1+ is bonded to six O2- atoms to form KO6 octahedra that share corners with two equivalent SbO6 octahedra, corners with four equivalent KO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.29 Å) and two longer (2.36 Å) K–O bond lengths. There are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with four equivalent KO6 octahedra, and edges with eight equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.26 Å) and four longer (2.29 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 MgO6 octahedra, edges with four equivalent SbO6 octahedra, and edges with eight equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.23 Å) and four longer (2.29 Å) Mg–O bond lengths. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, edges with two equivalent KO6 octahedra, edges with two equivalent SbO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–13°. There are a spread of Mg–O bond distances ranging from 2.09–2.41 Å. Sb3+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with two equivalent KO6 octahedra, corners with four equivalent SbO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.14 Å) and four longer (2.29 Å) Sb–O bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to one K1+, four equivalent Mg2+, and one Sb3+ atom to form OKMg4Sb octahedra that share corners with six equivalent OKMg4Sb octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–13°. In the second O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OKMg4Sb octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the third O2- site, O2- is bonded to two equivalent K1+ and four Mg2+ atoms to form OK2Mg4 octahedra that share corners with six OK2Mg4 octahedra and edges with twelve OKMg4Sb octahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth O2- site, O2- is bonded to four Mg2+ and two equivalent Sb3+ atoms to form OMg4Sb2 octahedra that share corners with six OK2Mg4 octahedra and edges with twelve OKMg4Sb octahedra. The corner-sharing octahedral tilt angles are 0°. In the fifth O2- site, O2- is bonded to two equivalent K1+ and four Mg2+ atoms to form OK2Mg4 octahedra that share corners with six OMg4Sb2 octahedra and edges with twelve OKMg4Sb octahedra. The corner-sharing octahedral tilt angles are 0°. Both O–Mg bond lengths are 2.09 Å.