DOI: 10.17188/1275044
title: Materials Data on Na4Si2Te5 by Materials Project

description: Na4Si2Te5 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are eight inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six Te+0.80- atoms to form NaTe6 octahedra that share corners with two NaTe6 octahedra, corners with three SiSiTe3 tetrahedra, edges with nine NaTe6 octahedra, and edges with two SiSiTe3 tetrahedra. The corner-sharing octahedra tilt angles range from 6–10°. There are a spread of Na–Te bond distances ranging from 3.11–3.61 Å. In the second Na1+ site, Na1+ is bonded to six Te+0.80- atoms to form NaTe6 octahedra that share corners with five NaTe6 octahedra, a cornercorner with one SiSiTe3 tetrahedra, edges with eight NaTe6 octahedra, and edges with three SiSiTe3 tetrahedra. The corner-sharing octahedra tilt angles range from 7–16°. There are a spread of Na–Te bond distances ranging from 3.24–3.38 Å. In the third Na1+ site, Na1+ is bonded to six Te+0.80- atoms to form distorted NaTe6 octahedra that share corners with five NaTe6 octahedra, corners with five SiSiTe3 tetrahedra, edges with six NaTe6 octahedra, and an edgeedge with one SiSiTe3 tetrahedra. The corner-sharing octahedra tilt angles range from 3–16°. There are a spread of Na–Te bond distances ranging from 3.21–3.84 Å. In the fourth Na1+ site, Na1+ is bonded to six Te+0.80- atoms to form NaTe6 octahedra that share corners with five NaTe6 octahedra, corners with seven SiSiTe3 tetrahedra, and edges with nine NaTe6 octahedra. The corner-sharing octahedra tilt angles range from 5–16°. There are a spread of Na–Te bond distances ranging from 3.19–3.63 Å. In the fifth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five Te+0.80- atoms. There are a spread of Na–Te bond distances ranging from 3.19–3.33 Å. In the sixth Na1+ site, Na1+ is bonded to six Te+0.80- atoms to form NaTe6 octahedra that share corners with two NaTe6 octahedra, corners with five SiSiTe3 tetrahedra, edges with eight NaTe6 octahedra, and an edgeedge with one SiSiTe3 tetrahedra. The corner-sharing octahedra tilt angles range from 6–10°. There are a spread of Na–Te bond distances ranging from 3.23–3.55 Å. In the seventh Na1+ site, Na1+ is bonded to six Te+0.80- atoms to form NaTe6 octahedra that share corners with four NaTe6 octahedra, corners with five SiSiTe3 tetrahedra, edges with nine NaTe6 octahedra, and an edgeedge with one SiSiTe3 tetrahedra. The corner-sharing octahedra tilt angles range from 5–10°. There are a spread of Na–Te bond distances ranging from 3.20–3.62 Å. In the eighth Na1+ site, Na1+ is bonded to six Te+0.80- atoms to form NaTe6 octahedra that share corners with three NaTe6 octahedra, corners with five SiSiTe3 tetrahedra, edges with eight NaTe6 octahedra, and an edgeedge with one SiSiTe3 tetrahedra. The corner-sharing octahedra tilt angles range from 3–16°. There are a spread of Na–Te bond distances ranging from 3.16–3.55 Å. There are four inequivalent Si sites. In the first Si site, Si is bonded to one Si and three Te+0.80- atoms to form SiSiTe3 tetrahedra that share corners with three TeNa5Si octahedra, corners with seven NaTe6 octahedra, a cornercorner with one SiSiTe3 tetrahedra, and edges with two NaTe6 octahedra. The corner-sharing octahedra tilt angles range from 17–85°. The Si–Si bond length is 2.36 Å. There are a spread of Si–Te bond distances ranging from 2.49–2.61 Å. In the second Si site, Si is bonded to one Si and three Te+0.80- atoms to form SiSiTe3 tetrahedra that share corners with two TeNa5Si octahedra, corners with nine NaTe6 octahedra, and edges with two NaTe6 octahedra. The corner-sharing octahedra tilt angles range from 17–79°. The Si–Si bond length is 2.37 Å. There are two shorter (2.52 Å) and one longer (2.53 Å) Si–Te bond lengths. In the third Si site, Si is bonded to one Si and three Te+0.80- atoms to form SiSiTe3 tetrahedra that share corners with three TeNa5Si octahedra, corners with eight NaTe6 octahedra, corners with two SiSiTe3 tetrahedra, and edges with two NaTe6 octahedra. The corner-sharing octahedra tilt angles range from 9–81°. There are one shorter (2.50 Å) and two longer (2.59 Å) Si–Te bond lengths. In the fourth Si site, Si is bonded to one Si and three Te+0.80- atoms to form SiSiTe3 tetrahedra that share corners with two TeNa5Si octahedra, corners with seven NaTe6 octahedra, a cornercorner with one SiSiTe3 tetrahedra, and edges with three NaTe6 octahedra. The corner-sharing octahedra tilt angles range from 7–82°. There are a spread of Si–Te bond distances ranging from 2.50–2.62 Å. There are ten inequivalent Te+0.80- sites. In the first Te+0.80- site, Te+0.80- is bonded to five Na1+ and one Si atom to form TeNa5Si octahedra that share corners with seven TeNa5Si octahedra, a cornercorner with one SiSiTe3 tetrahedra, and edges with nine TeNa5Si octahedra. The corner-sharing octahedra tilt angles range from 4–93°. In the second Te+0.80- site, Te+0.80- is bonded to five Na1+ and one Si atom to form TeNa5Si octahedra that share corners with five TeNa5Si octahedra, a cornercorner with one SiSiTe3 tetrahedra, and edges with ten TeNa5Si octahedra. The corner-sharing octahedra tilt angles range from 3–92°. In the third Te+0.80- site, Te+0.80- is bonded to five Na1+ and one Si atom to form TeNa5Si octahedra that share corners with seven TeNa5Si octahedra, a cornercorner with one SiSiTe3 tetrahedra, and edges with nine TeNa5Si octahedra. The corner-sharing octahedra tilt angles range from 7–89°. In the fourth Te+0.80- site, Te+0.80- is bonded to four Na1+ and two Si atoms to form distorted TeNa4Si2 octahedra that share corners with seven TeNa5Si octahedra, corners with two SiSiTe3 tetrahedra, and edges with eight TeNa5Si octahedra. The corner-sharing octahedra tilt angles range from 5–95°. In the fifth Te+0.80- site, Te+0.80- is bonded in a 5-coordinate geometry to three Na1+ and two Si atoms. In the sixth Te+0.80- site, Te+0.80- is bonded to five Na1+ and one Si atom to form TeNa5Si octahedra that share corners with five TeNa5Si octahedra, a cornercorner with one SiSiTe3 tetrahedra, and edges with nine TeNa5Si octahedra. The corner-sharing octahedra tilt angles range from 3–82°. In the seventh Te+0.80- site, Te+0.80- is bonded to five Na1+ and one Si atom to form TeNa5Si octahedra that share corners with six TeNa5Si octahedra, a cornercorner with one SiSiTe3 tetrahedra, and edges with nine TeNa5Si octahedra. The corner-sharing octahedra tilt angles range from 6–95°. In the eighth Te+0.80- site, Te+0.80- is bonded to five Na1+ and one Si atom to form TeNa5Si octahedra that share corners with six TeNa5Si octahedra, a cornercorner with one SiSiTe3 tetrahedra, and edges with nine TeNa5Si octahedra. The corner-sharing octahedra tilt angles range from 4–90°. In the ninth Te+0.80- site, Te+0.80- is bonded to five Na1+ and one Si atom to form TeNa5Si octahedra that share corners with six TeNa5Si octahedra, a cornercorner with one SiSiTe3 tetrahedra, and edges with nine TeNa5Si octahedra. The corner-sharing octahedra tilt angles range from 5–88°. In the tenth Te+0.80- site, Te+0.80- is bonded to five Na1+ and one Si atom to form distorted TeNa5Si octahedra that share corners with seven TeNa5Si octahedra, a cornercorner with one SiSiTe3 tetrahedra, and edges with eight TeNa5Si octahedra. The corner-sharing octahedra tilt angles range from 4–85°.