Ca7Sn6 crystallizes in the orthorhombic Pnma space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one Sn(1), one Sn(4), two equivalent Sn(2), and two equivalent Sn(3) atoms. In the second Ca site, Ca(2) is bonded to one Sn(3), two equivalent Sn(1), two equivalent Sn(2), and two equivalent Sn(4) atoms to form distorted CaSn7 pentagonal bipyramids that share corners with two equivalent Ca(4)Sn6 octahedra, corners with two equivalent Ca(2)Sn7 pentagonal bipyramids, faces with two equivalent Ca(4)Sn6 octahedra, and faces with three equivalent Ca(2)Sn7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 45-48°. In the third Ca site, Ca(3) is bonded in a 7-coordinate geometry to three equivalent Sn(2) and four equivalent Sn(1) atoms. In the fourth Ca site, Ca(4) is bonded to two equivalent Sn(2), two equivalent Sn(3), and two equivalent Sn(4) atoms to form distorted CaSn6 octahedra that share corners with four equivalent Ca(4)Sn6 octahedra, corners with four equivalent Ca(2)Sn7 pentagonal bipyramids, and faces with four equivalent Ca(2)Sn7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 52-54°. There are four inequivalent Sn sites. In the first Sn site, Sn(2) is bonded in a 9-coordinate geometry to one Ca(4), two equivalent Ca(1), two equivalent Ca(2), three equivalent Ca(3), and one Sn(1) atom. In the second Sn site, Sn(3) is bonded in a 9-coordinate geometry to two equivalent Ca(2), two equivalent Ca(4), four equivalent Ca(1), and one Sn(4) atom. In the third Sn site, Sn(4) is bonded in a 9-coordinate geometry to two equivalent Ca(1), two equivalent Ca(4), four equivalent Ca(2), and one Sn(3) atom. In the fourth Sn site, Sn(1) is bonded in a 9-coordinate geometry to one Ca(1), two equivalent Ca(2), four equivalent Ca(3), one Sn(1), and one Sn(2) atom.
Ca7Sn6 crystallizes in the orthorhombic Pnma space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one Sn(1), one Sn(4), two equivalent Sn(2), and two equivalent Sn(3) atoms. The Ca(1)-Sn(1) bond length is 3.19 Å. The Ca(1)-Sn(4) bond length is 3.37 Å. There is one shorter (3.25 Å) and one longer (3.35 Å) Ca(1)-Sn(2) bond length. There is one shorter (3.17 Å) and one longer (3.18 Å) Ca(1)-Sn(3) bond length. In the second Ca site, Ca(2) is bonded to one Sn(3), two equivalent Sn(1), two equivalent Sn(2), and two equivalent Sn(4) atoms to form distorted CaSn7 pentagonal bipyramids that share corners with two equivalent Ca(4)Sn6 octahedra, corners with two equivalent Ca(2)Sn7 pentagonal bipyramids, faces with two equivalent Ca(4)Sn6 octahedra, and faces with three equivalent Ca(2)Sn7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 45-48°. The Ca(2)-Sn(3) bond length is 3.51 Å. There is one shorter (3.39 Å) and one longer (3.53 Å) Ca(2)-Sn(1) bond length. There is one shorter (3.35 Å) and one longer (3.43 Å) Ca(2)-Sn(2) bond length. Both Ca(2)-Sn(4) bond lengths are 3.37 Å. In the third Ca site, Ca(3) is bonded in a 7-coordinate geometry to three equivalent Sn(2) and four equivalent Sn(1) atoms. There is one shorter (3.35 Å) and two longer (3.44 Å) Ca(3)-Sn(2) bond lengths. There are a spread of Ca(3)-Sn(1) bond distances ranging from 3.27-3.62 Å. In the fourth Ca site, Ca(4) is bonded to two equivalent Sn(2), two equivalent Sn(3), and two equivalent Sn(4) atoms to form distorted CaSn6 octahedra that share corners with four equivalent Ca(4)Sn6 octahedra, corners with four equivalent Ca(2)Sn7 pentagonal bipyramids, and faces with four equivalent Ca(2)Sn7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 52-54°. Both Ca(4)-Sn(2) bond lengths are 3.62 Å. There is one shorter (3.13 Å) and one longer (3.49 Å) Ca(4)-Sn(3) bond length. There is one shorter (3.18 Å) and one longer (3.20 Å) Ca(4)-Sn(4) bond length. There are four inequivalent Sn sites. In the first Sn site, Sn(2) is bonded in a 9-coordinate geometry to one Ca(4), two equivalent Ca(1), two equivalent Ca(2), three equivalent Ca(3), and one Sn(1) atom. The Sn(2)-Sn(1) bond length is 2.96 Å. In the second Sn site, Sn(3) is bonded in a 9-coordinate geometry to two equivalent Ca(2), two equivalent Ca(4), four equivalent Ca(1), and one Sn(4) atom. The Sn(3)-Sn(4) bond length is 2.91 Å. In the third Sn site, Sn(4) is bonded in a 9-coordinate geometry to two equivalent Ca(1), two equivalent Ca(4), four equivalent Ca(2), and one Sn(3) atom. In the fourth Sn site, Sn(1) is bonded in a 9-coordinate geometry to one Ca(1), two equivalent Ca(2), four equivalent Ca(3), one Sn(1), and one Sn(2) atom. The Sn(1)-Sn(1) bond length is 2.93 Å.