DOE OSTI2020
Sm3(Sb7Te12)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded to seven Te2- atoms to form distorted SmTe7 pentagonal bipyramids that share corners with three SbTe6 pentagonal pyramids, an edgeedge with one SbTe6 octahedra, and edges with two SbTe6 pentagonal pyramids. There are a spread of Sm–Te bond distances ranging from 3.12–3.36 Å. In the second Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight Te2- atoms. There are a spread of Sm–Te bond distances ranging from 3.10–3.49 Å. In the third Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight Te2- atoms. There are a spread of Sm–Te bond distances ranging from 3.18–3.50 Å. There are fourteen inequivalent Sb+2.79+ sites. In the first Sb+2.79+ site, Sb+2.79+ is bonded in a 6-coordinate geometry to six Te2- atoms. There are a spread of Sb–Te bond distances ranging from 2.96–3.58 Å. In the second Sb+2.79+ site, Sb+2.79+ is bonded to six Te2- atoms to form distorted SbTe6 pentagonal pyramids that share a cornercorner with one SbTe6 octahedra, a cornercorner with one SmTe7 pentagonal bipyramid, corners with three equivalent SbTe6 pentagonal pyramids, an edgeedge with one SmTe7 pentagonal bipyramid, an edgeedge with one SbTe6 pentagonal pyramid, and a faceface with one SbTe6 octahedra. The corner-sharing octahedral tilt angles are 40°. There are a spread of Sb–Te bond distances ranging from 2.87–3.50 Å. In the third Sb+2.79+ site, Sb+2.79+ is bonded in a distorted octahedral geometry to six Te2- atoms. There are a spread of Sb–Te bond distances ranging from 2.96–3.39 Å. In the fourth Sb+2.79+ site, Sb+2.79+ is bonded to six Te2- atoms to form distorted SbTe6 octahedra that share corners with six SbTe6 pentagonal pyramids, an edgeedge with one SmTe7 pentagonal bipyramid, and a faceface with one SbTe6 pentagonal pyramid. There are a spread of Sb–Te bond distances ranging from 2.88–3.36 Å. In the fifth Sb+2.79+ site, Sb+2.79+ is bonded to six Te2- atoms to form a mixture of distorted edge and corner-sharing SbTe6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 37–80°. There are a spread of Sb–Te bond distances ranging from 2.93–3.43 Å. In the sixth Sb+2.79+ site, Sb+2.79+ is bonded in a 6-coordinate geometry to six Te2- atoms. There are a spread of Sb–Te bond distances ranging from 2.95–3.53 Å. In the seventh Sb+2.79+ site, Sb+2.79+ is bonded to six Te2- atoms to form SbTe6 pentagonal pyramids that share corners with two equivalent SbTe6 octahedra, corners with two equivalent SmTe7 pentagonal bipyramids, corners with four SbTe6 pentagonal pyramids, and an edgeedge with one SmTe7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Sb–Te bond distances ranging from 2.96–3.38 Å. In the eighth Sb+2.79+ site, Sb+2.79+ is bonded in a 3-coordinate geometry to three Te2- atoms. There are a spread of Sb–Te bond distances ranging from 2.82–2.96 Å. In the ninth Sb+2.79+ site, Sb+2.79+ is bonded in a 6-coordinate geometry to six Te2- atoms. There are a spread of Sb–Te bond distances ranging from 2.85–3.55 Å. In the tenth Sb+2.79+ site, Sb+2.79+ is bonded in a 7-coordinate geometry to seven Te2- atoms. There are a spread of Sb–Te bond distances ranging from 2.97–3.62 Å. In the eleventh Sb+2.79+ site, Sb+2.79+ is bonded in a 4-coordinate geometry to five Te2- atoms. There are a spread of Sb–Te bond distances ranging from 2.86–3.63 Å. In the twelfth Sb+2.79+ site, Sb+2.79+ is bonded in a 4-coordinate geometry to four Te2- atoms. There are a spread of Sb–Te bond distances ranging from 2.92–3.10 Å. In the thirteenth Sb+2.79+ site, Sb+2.79+ is bonded in a 4-coordinate geometry to four Te2- atoms. There are a spread of Sb–Te bond distances ranging from 2.84–3.46 Å. In the fourteenth Sb+2.79+ site, Sb+2.79+ is bonded in a distorted rectangular see-saw-like geometry to four Te2- atoms. There are a spread of Sb–Te bond distances ranging from 2.88–3.51 Å. There are twenty-four inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 4-coordinate geometry to one Sm3+ and three Sb+2.79+ atoms. In the second Te2- site, Te2- is bonded in a 2-coordinate geometry to two Sm3+ and two Sb+2.79+ atoms. In the third Te2- site, Te2- is bonded to four Sb+2.79+ atoms to form distorted corner-sharing TeSb4 trigonal pyramids. In the fourth Te2- site, Te2- is bonded in a 4-coordinate geometry to one Sm3+ and four Sb+2.79+ atoms. In the fifth Te2- site, Te2- is bonded in a 4-coordinate geometry to five Sb+2.79+ atoms. In the sixth Te2- site, Te2- is bonded in a 4-coordinate geometry to one Sm3+ and three Sb+2.79+ atoms. In the seventh Te2- site, Te2- is bonded in a 5-coordinate geometry to three Sm3+ and two Sb+2.79+ atoms. In the eighth Te2- site, Te2- is bonded in a 3-coordinate geometry to two Sm3+ and three Sb+2.79+ atoms. In the ninth Te2- site, Te2- is bonded in a 5-coordinate geometry to one Sm3+ and four Sb+2.79+ atoms. In the tenth Te2- site, Te2- is bonded in a 1-coordinate geometry to one Sm3+ and three Sb+2.79+ atoms. In the eleventh Te2- site, Te2- is bonded in a 3-coordinate geometry to four Sb+2.79+ atoms. In the twelfth Te2- site, Te2- is bonded to four Sb+2.79+ atoms to form distorted corner-sharing TeSb4 trigonal pyramids. In the thirteenth Te2- site, Te2- is bonded in a 3-coordinate geometry to one Sm3+ and two Sb+2.79+ atoms. In the fourteenth Te2- site, Te2- is bonded in a 3-coordinate geometry to four Sb+2.79+ atoms. In the fifteenth Te2- site, Te2- is bonded in a 4-coordinate geometry to four Sb+2.79+ atoms. In the sixteenth Te2- site, Te2- is bonded in a 2-coordinate geometry to four Sb+2.79+ atoms. In the seventeenth Te2- site, Te2- is bonded in a 1-coordinate geometry to one Sm3+ and three Sb+2.79+ atoms. In the eighteenth Te2- site, Te2- is bonded in a 3-coordinate geometry to two Sm3+ and two Sb+2.79+ atoms. In the nineteenth Te2- site, Te2- is bonded in a 3-coordinate geometry to two Sm3+ and one Sb+2.79+ atom. In the twentieth Te2- site, Te2- is bonded in a 4-coordinate geometry to two Sm3+ and two Sb+2.79+ atoms. In the twenty-first Te2- site, Te2- is bonded in a 3-coordinate geometry to four Sb+2.79+ atoms. In the twenty-second Te2- site, Te2- is bonded in a 3-coordinate geometry to one Sm3+ and two Sb+2.79+ atoms. In the twenty-third Te2- site, Te2- is bonded in a 2-coordinate geometry to four Sb+2.79+ atoms. In the twenty-fourth Te2- site, Te2- is bonded in a 3-coordinate geometry to two Sm3+ and two Sb+2.79+ atoms.