Materials Data on Si3N4 by Materials Project

Abstract

Si3N4 crystallizes in the trigonal P31c space group. The structure is three-dimensional. there are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded in a distorted see-saw-like geometry to four N3- atoms. There are a spread of Si–N bond distances ranging from 1.79–2.12 Å. In the second Si4+ site, Si4+ is bonded to five N3- atoms to form a mixture of distorted edge and corner-sharing SiN5 trigonal bipyramids. There are a spread of Si–N bond distances ranging from 1.77–1.94 Å. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted trigonal planar geometry to three Si4+ atoms. In the second N3- site, N3- is bonded to four Si4+ atoms to form distorted corner-sharing NSi4 trigonal pyramids. In the third N3- site, N3- is bonded in a 4-coordinate geometry to three equivalent Si4+ and one N3- atom. The N–N bond length is 1.27 Å. In the fourth N3- site, N3- is bonded in a 4-coordinate geometry to three equivalent Si4+ and one N3- atom.