DOE OSTI2020
LiSr2SiN3 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four N3- atoms. There are a spread of Li–N bond distances ranging from 2.01–2.53 Å. In the second Li1+ site, Li1+ is bonded in a distorted T-shaped geometry to three N3- atoms. There are one shorter (1.90 Å) and two longer (2.29 Å) Li–N bond lengths. There are four inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of Sr–N bond distances ranging from 2.54–2.75 Å. In the second Sr2+ site, Sr2+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of Sr–N bond distances ranging from 2.55–3.02 Å. In the third Sr2+ site, Sr2+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of Sr–N bond distances ranging from 2.55–2.98 Å. In the fourth Sr2+ site, Sr2+ is bonded in a 4-coordinate geometry to five N3- atoms. There are a spread of Sr–N bond distances ranging from 2.55–2.98 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four N3- atoms to form corner-sharing SiN4 tetrahedra. There are a spread of Si–N bond distances ranging from 1.73–1.78 Å. In the second Si4+ site, Si4+ is bonded to four N3- atoms to form corner-sharing SiN4 tetrahedra. There are a spread of Si–N bond distances ranging from 1.74–1.83 Å. There are seven inequivalent N3- sites. In the first N3- site, N3- is bonded in a 2-coordinate geometry to two equivalent Li1+, two equivalent Sr2+, and two equivalent Si4+ atoms. In the second N3- site, N3- is bonded in a 4-coordinate geometry to two equivalent Li1+, two equivalent Sr2+, and two equivalent Si4+ atoms. In the third N3- site, N3- is bonded in a 6-coordinate geometry to two Li1+, two Sr2+, and two Si4+ atoms. In the fourth N3- site, N3- is bonded in a distorted see-saw-like geometry to two Li1+, two Sr2+, and two Si4+ atoms. In the fifth N3- site, N3- is bonded to five Sr2+ and one Si4+ atom to form distorted edge-sharing NSr5Si octahedra. In the sixth N3- site, N3- is bonded to five Sr2+ and one Si4+ atom to form distorted NSr5Si octahedra that share corners with four equivalent NSr5Li octahedra and edges with five NSr5Si octahedra. The corner-sharing octahedra tilt angles range from 5–16°. In the seventh N3- site, N3- is bonded to one Li1+ and five Sr2+ atoms to form a mixture of distorted corner and edge-sharing NSr5Li octahedra. The corner-sharing octahedra tilt angles range from 5–16°.