Materials Data on LiCa10MgSb9 by Materials Project
LiCa10MgSb9 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Li1+ is bonded in a see-saw-like geometry to four Sb+2.56- atoms. There are two shorter (3.00 Å) and two longer (3.02 Å) Li–Sb bond lengths. There are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six Sb+2.56- atoms to form CaSb6 octahedra that share corners with four equivalent CaSb6 octahedra, corners with seven equivalent CaSb7 pentagonal bipyramids, corners with two equivalent MgSb4 tetrahedra, edges with two equivalent CaSb6 octahedra, faces with two equivalent CaSb6 octahedra, and faces with three equivalent CaSb7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 28–51°. There are a spread of Ca–Sb bond distances ranging from 3.15–3.43 Å. In the second Ca2+ site, Ca2+ is bonded to seven Sb+2.56- atoms to form distorted CaSb7 pentagonal bipyramids that share corners with seven equivalent CaSb6 octahedra, corners with three equivalent CaSb7 pentagonal bipyramids, a cornercorner with one MgSb4 tetrahedra, edges with two equivalent CaSb7 pentagonal bipyramids, an edgeedge with one MgSb4 tetrahedra, faces with three equivalent CaSb6 octahedra, and faces with four equivalent CaSb7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 33–53°. There are a spread of Ca–Sb bond distances ranging from 3.15–3.71 Å. In the third Ca2+ site, Ca2+ is bonded in a 4-coordinate geometry to four Sb+2.56- atoms. There are two shorter (3.18 Å) and two longer (3.30 Å) Ca–Sb bond lengths. In the fourth Ca2+ site, Ca2+ is bonded in a 5-coordinate geometry to five Sb+2.56- atoms. There are a spread of Ca–Sb bond distances ranging from 3.13–3.49 Å. Mg2+ is bonded to four Sb+2.56- atoms to form MgSb4 tetrahedra that share corners with eight equivalent CaSb6 octahedra, corners with four equivalent CaSb7 pentagonal bipyramids, edges with four equivalent CaSb7 pentagonal bipyramids, and an edgeedge with one MgSb4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–60°. All Mg–Sb bond lengths are 2.89 Å. There are six inequivalent Sb+2.56- sites. In the first Sb+2.56- site, Sb+2.56- is bonded in a 6-coordinate geometry to four equivalent Ca2+ and two equivalent Mg2+ atoms. In the second Sb+2.56- site, Sb+2.56- is bonded in a 2-coordinate geometry to seven Ca2+ and one Sb+2.56- atom. The Sb–Sb bond length is 2.97 Å. In the third Sb+2.56- site, Sb+2.56- is bonded in a 7-coordinate geometry to seven Ca2+ atoms. In the fourth Sb+2.56- site, Sb+2.56- is bonded in a 9-coordinate geometry to one Li1+, seven Ca2+, and one Sb+2.56- atom. In the fifth Sb+2.56- site, Sb+2.56- is bonded in a 9-coordinate geometry to one Li1+, seven Ca2+, and one Mg2+ atom. In the sixth Sb+2.56- site, Sb+2.56- is bonded in a 8-coordinate geometry to eight Ca2+ atoms.