Pt4Hg crystallizes in the trigonal R-3m space group. There are four inequivalent Pt sites. In the first Pt site, Pt(1) is bonded to three equivalent Pt(2), six equivalent Pt(1), and three equivalent Hg(1) atoms to form PtHg3Pt9 cuboctahedra that share corners with three equivalent Pt(2)Pt12 cuboctahedra, corners with nine equivalent Pt(1)Hg3Pt9 cuboctahedra, edges with six equivalent Hg(1)Hg6Pt6 cuboctahedra, edges with nine equivalent Pt(1)Hg3Pt9 cuboctahedra, edges with nine equivalent Pt(2)Pt12 cuboctahedra, faces with six equivalent Pt(1)Hg3Pt9 cuboctahedra, faces with six equivalent Pt(2)Pt12 cuboctahedra, and faces with six equivalent Hg(1)Hg6Pt6 cuboctahedra. In the second Pt site, Pt(2) is bonded to three equivalent Pt(1) and nine equivalent Pt(2) atoms to form PtPt12 cuboctahedra that share corners with three equivalent Pt(1)Hg3Pt9 cuboctahedra, corners with three equivalent Hg(1)Hg6Pt6 cuboctahedra, corners with six equivalent Pt(2)Pt12 cuboctahedra, edges with three equivalent Hg(1)Hg6Pt6 cuboctahedra, edges with nine equivalent Pt(1)Hg3Pt9 cuboctahedra, edges with twelve equivalent Pt(2)Pt12 cuboctahedra, faces with six equivalent Pt(1)Hg3Pt9 cuboctahedra, and faces with twelve equivalent Pt(2)Pt12 cuboctahedra. In the third Pt site, Pt(2) is bonded to three equivalent Pt(1) and nine equivalent Pt(2) atoms to form PtPt12 cuboctahedra that share corners with three equivalent Pt(1)Hg3Pt9 cuboctahedra, corners with three equivalent Hg(1)Hg6Pt6 cuboctahedra, corners with six equivalent Pt(2)Pt12 cuboctahedra, edges with three equivalent Hg(1)Hg6Pt6 cuboctahedra, edges with nine equivalent Pt(1)Hg3Pt9 cuboctahedra, edges with twelve equivalent Pt(2)Pt12 cuboctahedra, faces with six equivalent Pt(1)Hg3Pt9 cuboctahedra, and faces with twelve equivalent Pt(2)Pt12 cuboctahedra. In the fourth Pt site, Pt(2) is bonded to three equivalent Pt(1) and nine Pt(2,2) atoms to form PtPt12 cuboctahedra that share corners with three equivalent Pt(1)Hg3Pt9 cuboctahedra; corners with three equivalent Hg(1)Hg6Pt6 cuboctahedra; corners with six equivalent Pt(2)Pt12 cuboctahedra; edges with three equivalent Hg(1)Hg6Pt6 cuboctahedra; edges with nine equivalent Pt(1)Hg3Pt9 cuboctahedra; edges with twelve Pt(2,2)Pt12 cuboctahedra; faces with six equivalent Pt(1)Hg3Pt9 cuboctahedra; and faces with twelve Pt(2,2)Pt12 cuboctahedra. Hg(1) is bonded to six equivalent Pt(1) and six equivalent Hg(1) atoms to form HgHg6Pt6 cuboctahedra that share corners with six Pt(2,2)Pt12 cuboctahedra; corners with six equivalent Hg(1)Hg6Pt6 cuboctahedra; edges with six Pt(2,2)Pt12 cuboctahedra; edges with six equivalent Hg(1)Hg6Pt6 cuboctahedra; edges with twelve equivalent Pt(1)Hg3Pt9 cuboctahedra; faces with six equivalent Hg(1)Hg6Pt6 cuboctahedra; and faces with twelve equivalent Pt(1)Hg3Pt9 cuboctahedra.
Pt4Hg crystallizes in the trigonal R-3m space group. There are four inequivalent Pt sites. In the first Pt site, Pt(1) is bonded to three equivalent Pt(2), six equivalent Pt(1), and three equivalent Hg(1) atoms to form PtHg3Pt9 cuboctahedra that share corners with three equivalent Pt(2)Pt12 cuboctahedra, corners with nine equivalent Pt(1)Hg3Pt9 cuboctahedra, edges with six equivalent Hg(1)Hg6Pt6 cuboctahedra, edges with nine equivalent Pt(1)Hg3Pt9 cuboctahedra, edges with nine equivalent Pt(2)Pt12 cuboctahedra, faces with six equivalent Pt(1)Hg3Pt9 cuboctahedra, faces with six equivalent Pt(2)Pt12 cuboctahedra, and faces with six equivalent Hg(1)Hg6Pt6 cuboctahedra. All Pt(1)-Pt(2) bond lengths are 2.78 Å. All Pt(1)-Pt(1) bond lengths are 2.91 Å. All Pt(1)-Hg(1) bond lengths are 2.92 Å. In the second Pt site, Pt(2) is bonded to three equivalent Pt(1) and nine equivalent Pt(2) atoms to form PtPt12 cuboctahedra that share corners with three equivalent Pt(1)Hg3Pt9 cuboctahedra, corners with three equivalent Hg(1)Hg6Pt6 cuboctahedra, corners with six equivalent Pt(2)Pt12 cuboctahedra, edges with three equivalent Hg(1)Hg6Pt6 cuboctahedra, edges with nine equivalent Pt(1)Hg3Pt9 cuboctahedra, edges with twelve equivalent Pt(2)Pt12 cuboctahedra, faces with six equivalent Pt(1)Hg3Pt9 cuboctahedra, and faces with twelve equivalent Pt(2)Pt12 cuboctahedra. There are three shorter (2.76 Å) and six longer (2.91 Å) Pt(2)-Pt(2) bond lengths. In the third Pt site, Pt(2) is bonded to three equivalent Pt(1) and nine equivalent Pt(2) atoms to form PtPt12 cuboctahedra that share corners with three equivalent Pt(1)Hg3Pt9 cuboctahedra, corners with three equivalent Hg(1)Hg6Pt6 cuboctahedra, corners with six equivalent Pt(2)Pt12 cuboctahedra, edges with three equivalent Hg(1)Hg6Pt6 cuboctahedra, edges with nine equivalent Pt(1)Hg3Pt9 cuboctahedra, edges with twelve equivalent Pt(2)Pt12 cuboctahedra, faces with six equivalent Pt(1)Hg3Pt9 cuboctahedra, and faces with twelve equivalent Pt(2)Pt12 cuboctahedra. All Pt(2)-Pt(1) bond lengths are 2.78 Å. There are three shorter (2.76 Å) and six longer (2.91 Å) Pt(2)-Pt(2) bond lengths. In the fourth Pt site, Pt(2) is bonded to three equivalent Pt(1) and nine Pt(2,2) atoms to form PtPt12 cuboctahedra that share corners with three equivalent Pt(1)Hg3Pt9 cuboctahedra; corners with three equivalent Hg(1)Hg6Pt6 cuboctahedra; corners with six equivalent Pt(2)Pt12 cuboctahedra; edges with three equivalent Hg(1)Hg6Pt6 cuboctahedra; edges with nine equivalent Pt(1)Hg3Pt9 cuboctahedra; edges with twelve Pt(2,2)Pt12 cuboctahedra; faces with six equivalent Pt(1)Hg3Pt9 cuboctahedra; and faces with twelve Pt(2,2)Pt12 cuboctahedra. All Pt(2)-Pt(1) bond lengths are 2.78 Å. There are three shorter (2.76 Å) and six longer (2.91 Å) Pt(2)-Pt(2,2) bond lengths. Hg(1) is bonded to six equivalent Pt(1) and six equivalent Hg(1) atoms to form HgHg6Pt6 cuboctahedra that share corners with six Pt(2,2)Pt12 cuboctahedra; corners with six equivalent Hg(1)Hg6Pt6 cuboctahedra; edges with six Pt(2,2)Pt12 cuboctahedra; edges with six equivalent Hg(1)Hg6Pt6 cuboctahedra; edges with twelve equivalent Pt(1)Hg3Pt9 cuboctahedra; faces with six equivalent Hg(1)Hg6Pt6 cuboctahedra; and faces with twelve equivalent Pt(1)Hg3Pt9 cuboctahedra. All Hg(1)-Hg(1) bond lengths are 2.91 Å.