Materials Data on Ca3(AlN2)2 by Materials Project

Abstract

Ca3(AlN2)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven N3- atoms. There are a spread of Ca–N bond distances ranging from 2.43–2.97 Å. In the second Ca2+ site, Ca2+ is bonded in a 4-coordinate geometry to five N3- atoms. There are a spread of Ca–N bond distances ranging from 2.39–3.13 Å. In the third Ca2+ site, Ca2+ is bonded in a 5-coordinate geometry to six N3- atoms. There are a spread of Ca–N bond distances ranging from 2.34–3.06 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four N3- atoms to form corner-sharing AlN4 tetrahedra. There are a spread of Al–N bond distances ranging from 1.88–1.95 Å. In the second Al3+ site, Al3+ is bonded to four N3- atoms to form a mixture of edge and corner-sharing AlN4 tetrahedra. There are a spread of Al–N bond distances ranging from 1.83–1.98 Å. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded to five Ca2+ and one Al3+ atom to form a mixture of distorted edge and corner-sharing NCa5Al octahedra. The corner-sharing octahedra tilt angles range from 13–72°. In the second N3- site, N3- is bonded in a 3-coordinate geometry to four Ca2+ and three Al3+ atoms. In the third N3- site, N3- is bonded to four Ca2+ and two Al3+ atoms to form a mixture of distorted edge and corner-sharing NCa4Al2 octahedra. The corner-sharing octahedra tilt angles range from 13–72°. In the fourth N3- site, N3- is bonded in a 2-coordinate geometry to five Ca2+ and two Al3+ atoms.