Mg4Pt5Sn6 is half-Heusler-like structured and crystallizes in the trigonal R3m space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 10-coordinate geometry to one Pt(5), three equivalent Pt(1), three equivalent Sn(4), and three equivalent Sn(5) atoms. In the second Mg site, Mg(2) is bonded to one Pt(1), three equivalent Pt(2), three equivalent Sn(2), and three equivalent Sn(5) atoms to form a mixture of distorted corner and face-sharing MgSn6Pt4 tetrahedra. In the third Mg site, Mg(3) is bonded to one Pt(2), three equivalent Pt(3), three equivalent Sn(2), and three equivalent Sn(3) atoms to form a mixture of distorted corner and face-sharing MgSn6Pt4 tetrahedra. In the fourth Mg site, Mg(4) is bonded to one Pt(3), three equivalent Pt(4), three equivalent Sn(1), and three equivalent Sn(3) atoms to form distorted MgSn6Pt4 tetrahedra that share corners with three equivalent Mg(3)Sn6Pt4 tetrahedra, corners with three equivalent Sn(6)Pt4 tetrahedra, faces with three equivalent Mg(3)Sn6Pt4 tetrahedra, and faces with six equivalent Mg(4)Sn6Pt4 tetrahedra. There are five inequivalent Pt sites. In the first Pt site, Pt(3) is bonded in a body-centered cubic geometry to one Mg(4), three equivalent Mg(3), one Sn(2), and three equivalent Sn(3) atoms. In the second Pt site, Pt(4) is bonded in a body-centered cubic geometry to three equivalent Mg(4), one Sn(3), one Sn(6), and three equivalent Sn(1) atoms. In the third Pt site, Pt(5) is bonded in a body-centered cubic geometry to one Mg(1), one Sn(1), three equivalent Sn(4), and three equivalent Sn(6) atoms. In the fourth Pt site, Pt(1) is bonded in a body-centered cubic geometry to one Mg(2), three equivalent Mg(1), one Sn(4), and three equivalent Sn(5) atoms. In the fifth Pt site, Pt(2) is bonded in a body-centered cubic geometry to one Mg(3), three equivalent Mg(2), one Sn(5), and three equivalent Sn(2) atoms. There are six inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 7-coordinate geometry to three equivalent Mg(4), one Pt(5), and three equivalent Pt(4) atoms. In the second Sn site, Sn(2) is bonded in a 10-coordinate geometry to three equivalent Mg(2), three equivalent Mg(3), one Pt(3), and three equivalent Pt(2) atoms. In the third Sn site, Sn(3) is bonded in a 10-coordinate geometry to three equivalent Mg(3), three equivalent Mg(4), one Pt(4), and three equivalent Pt(3) atoms. In the fourth Sn site, Sn(4) is bonded in a 7-coordinate geometry to three equivalent Mg(1), one Pt(1), and three equivalent Pt(5) atoms. In the fifth Sn site, Sn(5) is bonded in a 10-coordinate geometry to three equivalent Mg(1), three equivalent Mg(2), one Pt(2), and three equivalent Pt(1) atoms. In the sixth Sn site, Sn(6) is bonded to one Pt(4) and three equivalent Pt(5) atoms to form SnPt4 tetrahedra that share corners with three equivalent Mg(4)Sn6Pt4 tetrahedra and corners with six equivalent Sn(6)Pt4 tetrahedra.
Mg4Pt5Sn6 is half-Heusler-like structured and crystallizes in the trigonal R3m space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 10-coordinate geometry to one Pt(5), three equivalent Pt(1), three equivalent Sn(4), and three equivalent Sn(5) atoms. The Mg(1)-Pt(5) bond length is 2.82 Å. All Mg(1)-Pt(1) bond lengths are 2.77 Å. All Mg(1)-Sn(4) bond lengths are 3.15 Å. All Mg(1)-Sn(5) bond lengths are 3.20 Å. In the second Mg site, Mg(2) is bonded to one Pt(1), three equivalent Pt(2), three equivalent Sn(2), and three equivalent Sn(5) atoms to form a mixture of distorted corner and face-sharing MgSn6Pt4 tetrahedra. The Mg(2)-Pt(1) bond length is 2.75 Å. All Mg(2)-Pt(2) bond lengths are 2.77 Å. All Mg(2)-Sn(2) bond lengths are 3.20 Å. All Mg(2)-Sn(5) bond lengths are 3.18 Å. In the third Mg site, Mg(3) is bonded to one Pt(2), three equivalent Pt(3), three equivalent Sn(2), and three equivalent Sn(3) atoms to form a mixture of distorted corner and face-sharing MgSn6Pt4 tetrahedra. The Mg(3)-Pt(2) bond length is 2.78 Å. All Mg(3)-Pt(3) bond lengths are 2.76 Å. All Mg(3)-Sn(2) bond lengths are 3.20 Å. All Mg(3)-Sn(3) bond lengths are 3.21 Å. In the fourth Mg site, Mg(4) is bonded to one Pt(3), three equivalent Pt(4), three equivalent Sn(1), and three equivalent Sn(3) atoms to form distorted MgSn6Pt4 tetrahedra that share corners with three equivalent Mg(3)Sn6Pt4 tetrahedra, corners with three equivalent Sn(6)Pt4 tetrahedra, faces with three equivalent Mg(3)Sn6Pt4 tetrahedra, and faces with six equivalent Mg(4)Sn6Pt4 tetrahedra. The Mg(4)-Pt(3) bond length is 2.74 Å. All Mg(4)-Pt(4) bond lengths are 2.78 Å. All Mg(4)-Sn(1) bond lengths are 3.16 Å. All Mg(4)-Sn(3) bond lengths are 3.16 Å. There are five inequivalent Pt sites. In the first Pt site, Pt(3) is bonded in a body-centered cubic geometry to one Mg(4), three equivalent Mg(3), one Sn(2), and three equivalent Sn(3) atoms. The Pt(3)-Sn(2) bond length is 2.77 Å. All Pt(3)-Sn(3) bond lengths are 2.78 Å. In the second Pt site, Pt(4) is bonded in a body-centered cubic geometry to three equivalent Mg(4), one Sn(3), one Sn(6), and three equivalent Sn(1) atoms. The Pt(4)-Sn(3) bond length is 2.75 Å. The Pt(4)-Sn(6) bond length is 2.78 Å. All Pt(4)-Sn(1) bond lengths are 2.74 Å. In the third Pt site, Pt(5) is bonded in a body-centered cubic geometry to one Mg(1), one Sn(1), three equivalent Sn(4), and three equivalent Sn(6) atoms. The Pt(5)-Sn(1) bond length is 2.87 Å. All Pt(5)-Sn(4) bond lengths are 2.81 Å. All Pt(5)-Sn(6) bond lengths are 2.76 Å. In the fourth Pt site, Pt(1) is bonded in a body-centered cubic geometry to one Mg(2), three equivalent Mg(1), one Sn(4), and three equivalent Sn(5) atoms. The Pt(1)-Sn(4) bond length is 2.70 Å. All Pt(1)-Sn(5) bond lengths are 2.77 Å. In the fifth Pt site, Pt(2) is bonded in a body-centered cubic geometry to one Mg(3), three equivalent Mg(2), one Sn(5), and three equivalent Sn(2) atoms. The Pt(2)-Sn(5) bond length is 2.76 Å. All Pt(2)-Sn(2) bond lengths are 2.77 Å. There are six inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 7-coordinate geometry to three equivalent Mg(4), one Pt(5), and three equivalent Pt(4) atoms. In the second Sn site, Sn(2) is bonded in a 10-coordinate geometry to three equivalent Mg(2), three equivalent Mg(3), one Pt(3), and three equivalent Pt(2) atoms. In the third Sn site, Sn(3) is bonded in a 10-coordinate geometry to three equivalent Mg(3), three equivalent Mg(4), one Pt(4), and three equivalent Pt(3) atoms. In the fourth Sn site, Sn(4) is bonded in a 7-coordinate geometry to three equivalent Mg(1), one Pt(1), and three equivalent Pt(5) atoms. In the fifth Sn site, Sn(5) is bonded in a 10-coordinate geometry to three equivalent Mg(1), three equivalent Mg(2), one Pt(2), and three equivalent Pt(1) atoms. In the sixth Sn site, Sn(6) is bonded to one Pt(4) and three equivalent Pt(5) atoms to form SnPt4 tetrahedra that share corners with three equivalent Mg(4)Sn6Pt4 tetrahedra and corners with six equivalent Sn(6)Pt4 tetrahedra.