DOI: 10.17188/1758387
title: Materials Data on KMg14AlO16 by Materials Project

description: KMg14AlO16 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 KO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.19 Å) and four longer (2.37 Å) K–O bond lengths. There are four inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent KO6 octahedra, corners with two equivalent MgO6 octahedra, corners with two equivalent AlO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.91–2.35 Å. 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 two equivalent AlO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. There are a spread of Mg–O bond distances ranging from 2.13–2.20 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent KO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. There are a spread of Mg–O bond distances ranging from 2.14–2.20 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, an edgeedge with one KO6 octahedra, an edgeedge with one AlO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 2–13°. There are a spread of Mg–O bond distances ranging from 2.14–2.19 Å. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.94 Å) and two longer (2.19 Å) Al–O bond lengths. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded to five Mg2+ and one Al3+ atom to form a mixture of corner and edge-sharing OMg5Al octahedra. The corner-sharing octahedra tilt angles range from 0–12°. In the second O2- site, O2- is bonded to one K1+ and five Mg2+ atoms to form a mixture of corner and edge-sharing OKMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. Both O–Mg bond lengths are 2.20 Å. In the third O2- site, O2- is bonded to one K1+ and five Mg2+ atoms to form a mixture of corner and edge-sharing OKMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. There are two shorter (2.14 Å) and two longer (2.20 Å) O–Mg bond lengths. In the fourth 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 OMg5Al octahedra. The corner-sharing octahedra tilt angles range from 1–2°. In the fifth O2- site, O2- is bonded to four equivalent Mg2+ and two equivalent Al3+ atoms to form OMg4Al2 octahedra that share corners with six OMg4Al2 octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedral tilt angles are 0°. In the sixth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OMg4Al2 octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O2- site, O2- is bonded to two equivalent K1+ and four equivalent Mg2+ atoms to form OK2Mg4 octahedra that share corners with six OMg6 octahedra and edges with twelve OKMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the eighth O2- site, O2- is bonded to one K1+ and five Mg2+ atoms to form a mixture of corner and edge-sharing OKMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. The O–Mg bond length is 1.91 Å. In the ninth O2- site, O2- is bonded to one K1+ and five Mg2+ atoms to form a mixture of corner and edge-sharing OKMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. There are a spread of O–Mg bond distances ranging from 1.91–2.20 Å.