Materials Data on CaMg3SiN4 by Materials Project

Abstract

CaMg3SiN4 is Aluminum carbonitride-derived structured and crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. Ca2+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of Ca–N bond distances ranging from 2.56–2.89 Å. There are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four N3- atoms to form MgN4 trigonal pyramids that share corners with four equivalent SiN4 tetrahedra, corners with two equivalent MgN4 trigonal pyramids, and an edgeedge with one MgN4 trigonal pyramid. There are a spread of Mg–N bond distances ranging from 2.08–2.18 Å. In the second Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of Mg–N bond distances ranging from 2.09–2.66 Å. In the third Mg2+ site, Mg2+ is bonded to four N3- atoms to form MgN4 tetrahedra that share corners with two equivalent MgN4 tetrahedra, corners with two equivalent SiN4 tetrahedra, an edgeedge with one MgN4 tetrahedra, and an edgeedge with one SiN4 tetrahedra. There are a spread of Mg–N bond distances ranging from 1.99–2.21 Å. Si4+ is bonded to four N3- atoms to form SiN4 tetrahedra that share corners with two equivalent MgN4 tetrahedra, corners with four equivalent MgN4 trigonal pyramids, and an edgeedge with one MgN4 tetrahedra. There is one shorter (1.76 Å) and three longer (1.78 Å) Si–N bond length. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded in a 5-coordinate geometry to one Ca2+, three Mg2+, and one Si4+ atom. In the second N3- site, N3- is bonded in a 6-coordinate geometry to two equivalent Ca2+, three Mg2+, and one Si4+ atom. In the third N3- site, N3- is bonded in a 6-coordinate geometry to one Ca2+, four Mg2+, and one Si4+ atom. In the fourth N3- site, N3- is bonded in a 6-coordinate geometry to two equivalent Ca2+, three Mg2+, and one Si4+ atom.