Ca16Mg3Sn13 crystallizes in the orthorhombic Amm2 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), two equivalent Sn(5), and three equivalent Sn(3) atoms. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one Sn(2), two equivalent Sn(5), and three equivalent Sn(4) atoms. In the third Ca site, Ca(3) is bonded in a 6-coordinate geometry to one Sn(2), one Sn(3), two equivalent Sn(1), and two equivalent Sn(5) atoms. In the fourth Ca site, Ca(4) is bonded in a 6-coordinate geometry to one Sn(1), one Sn(4), two equivalent Sn(2), and two equivalent Sn(5) atoms. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to two equivalent Sn(2) and two equivalent Sn(4) atoms. In the second Mg site, Mg(2) is bonded in a distorted hexagonal planar geometry to two equivalent Sn(1), two equivalent Sn(3), and two equivalent Sn(6) atoms. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to two equivalent Sn(2) and two equivalent Sn(4) atoms. There are six inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 10-coordinate geometry to two equivalent Ca(1), two equivalent Ca(4), four equivalent Ca(3), one Mg(2), and one Sn(6) atom. In the second Sn site, Sn(2) is bonded in a 10-coordinate geometry to two equivalent Ca(2), two equivalent Ca(3), four equivalent Ca(4), one Mg(1), and one Mg(3) atom. In the third Sn site, Sn(3) is bonded in a 10-coordinate geometry to two equivalent Ca(3), six equivalent Ca(1), one Mg(2), and one Sn(6) atom. In the fourth Sn site, Sn(4) is bonded in a 10-coordinate geometry to two equivalent Ca(4), six equivalent Ca(2), one Mg(1), and one Mg(3) atom. In the fifth Sn site, Sn(5) is bonded in a 10-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), two equivalent Ca(4), and two equivalent Sn(5) atoms. In the sixth Sn site, Sn(6) is bonded in a distorted linear geometry to two equivalent Mg(2), two equivalent Sn(1), and two equivalent Sn(3) atoms.
Ca16Mg3Sn13 crystallizes in the orthorhombic Amm2 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), two equivalent Sn(5), and three equivalent Sn(3) atoms. The Ca(1)-Sn(1) bond length is 3.33 Å. Both Ca(1)-Sn(5) bond lengths are 3.23 Å. There are a spread of Ca(1)-Sn(3) bond distances ranging from 3.36-3.55 Å. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one Sn(2), two equivalent Sn(5), and three equivalent Sn(4) atoms. The Ca(2)-Sn(2) bond length is 3.33 Å. Both Ca(2)-Sn(5) bond lengths are 3.26 Å. There are a spread of Ca(2)-Sn(4) bond distances ranging from 3.37-3.54 Å. In the third Ca site, Ca(3) is bonded in a 6-coordinate geometry to one Sn(2), one Sn(3), two equivalent Sn(1), and two equivalent Sn(5) atoms. The Ca(3)-Sn(2) bond length is 3.35 Å. The Ca(3)-Sn(3) bond length is 3.35 Å. There is one shorter (3.53 Å) and one longer (3.55 Å) Ca(3)-Sn(1) bond length. Both Ca(3)-Sn(5) bond lengths are 3.24 Å. In the fourth Ca site, Ca(4) is bonded in a 6-coordinate geometry to one Sn(1), one Sn(4), two equivalent Sn(2), and two equivalent Sn(5) atoms. The Ca(4)-Sn(1) bond length is 3.38 Å. The Ca(4)-Sn(4) bond length is 3.32 Å. There is one shorter (3.53 Å) and one longer (3.54 Å) Ca(4)-Sn(2) bond length. There is one shorter (3.24 Å) and one longer (3.25 Å) Ca(4)-Sn(5) bond length. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to two equivalent Sn(2) and two equivalent Sn(4) atoms. Both Mg(1)-Sn(2) bond lengths are 3.08 Å. Both Mg(1)-Sn(4) bond lengths are 3.07 Å. In the second Mg site, Mg(2) is bonded in a distorted hexagonal planar geometry to two equivalent Sn(1), two equivalent Sn(3), and two equivalent Sn(6) atoms. Both Mg(2)-Sn(1) bond lengths are 3.07 Å. Both Mg(2)-Sn(3) bond lengths are 3.08 Å. There is one shorter (3.01 Å) and one longer (3.03 Å) Mg(2)-Sn(6) bond length. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to two equivalent Sn(2) and two equivalent Sn(4) atoms. Both Mg(3)-Sn(2) bond lengths are 3.09 Å. Both Mg(3)-Sn(4) bond lengths are 3.07 Å. There are six inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 10-coordinate geometry to two equivalent Ca(1), two equivalent Ca(4), four equivalent Ca(3), one Mg(2), and one Sn(6) atom. The Sn(1)-Sn(6) bond length is 3.08 Å. In the second Sn site, Sn(2) is bonded in a 10-coordinate geometry to two equivalent Ca(2), two equivalent Ca(3), four equivalent Ca(4), one Mg(1), and one Mg(3) atom. In the third Sn site, Sn(3) is bonded in a 10-coordinate geometry to two equivalent Ca(3), six equivalent Ca(1), one Mg(2), and one Sn(6) atom. The Sn(3)-Sn(6) bond length is 3.09 Å. In the fourth Sn site, Sn(4) is bonded in a 10-coordinate geometry to two equivalent Ca(4), six equivalent Ca(2), one Mg(1), and one Mg(3) atom. In the fifth Sn site, Sn(5) is bonded in a 10-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), two equivalent Ca(4), and two equivalent Sn(5) atoms. Both Sn(5)-Sn(5) bond lengths are 3.02 Å. In the sixth Sn site, Sn(6) is bonded in a distorted linear geometry to two equivalent Mg(2), two equivalent Sn(1), and two equivalent Sn(3) atoms.