SmHg2 crystallizes in the monoclinic C2/m space group. Sm(1) is bonded to eight equivalent Hg(1) atoms to form SmHg8 hexagonal bipyramids that share corners with eight equivalent Hg(1)Sm4Hg4 hexagonal bipyramids, edges with twelve equivalent Sm(1)Hg8 hexagonal bipyramids, and edges with twelve equivalent Hg(1)Sm4Hg4 hexagonal bipyramids. Hg(1) is bonded to four equivalent Sm(1) and four equivalent Hg(1) atoms to form distorted HgSm4Hg4 hexagonal bipyramids that share corners with four equivalent Sm(1)Hg8 hexagonal bipyramids, corners with four equivalent Hg(1)Sm4Hg4 hexagonal bipyramids, edges with six equivalent Sm(1)Hg8 hexagonal bipyramids, and edges with eighteen equivalent Hg(1)Sm4Hg4 hexagonal bipyramids.
SmHg2 crystallizes in the monoclinic C2/m space group. Sm(1) is bonded to eight equivalent Hg(1) atoms to form SmHg8 hexagonal bipyramids that share corners with eight equivalent Hg(1)Sm4Hg4 hexagonal bipyramids, edges with twelve equivalent Sm(1)Hg8 hexagonal bipyramids, and edges with twelve equivalent Hg(1)Sm4Hg4 hexagonal bipyramids. There are a spread of Sm(1)-Hg(1) bond distances ranging from 3.12-3.14 Å. Hg(1) is bonded to four equivalent Sm(1) and four equivalent Hg(1) atoms to form distorted HgSm4Hg4 hexagonal bipyramids that share corners with four equivalent Sm(1)Hg8 hexagonal bipyramids, corners with four equivalent Hg(1)Sm4Hg4 hexagonal bipyramids, edges with six equivalent Sm(1)Hg8 hexagonal bipyramids, and edges with eighteen equivalent Hg(1)Sm4Hg4 hexagonal bipyramids. There is one shorter (2.98 Å) and three longer (3.13 Å) Hg(1)-Hg(1) bond lengths.