YMoC2 crystallizes in the orthorhombic Pnma space group. Y(1) is bonded to three equivalent C(2) and four equivalent C(1) atoms to form distorted YC7 pentagonal bipyramids that share corners with four equivalent Y(1)C7 pentagonal bipyramids, corners with three equivalent Mo(1)C5 trigonal bipyramids, edges with four equivalent Y(1)C7 pentagonal bipyramids, edges with seven equivalent Mo(1)C5 trigonal bipyramids, and faces with two equivalent Y(1)C7 pentagonal bipyramids. Mo(1) is bonded to two equivalent C(1) and three equivalent C(2) atoms to form MoC5 trigonal bipyramids that share corners with three equivalent Y(1)C7 pentagonal bipyramids, corners with four equivalent Mo(1)C5 trigonal bipyramids, edges with seven equivalent Y(1)C7 pentagonal bipyramids, and edges with two equivalent Mo(1)C5 trigonal bipyramids. There are two inequivalent C sites. In the first C site, C(1) is bonded to four equivalent Y(1) and two equivalent Mo(1) atoms to form CY4Mo2 octahedra that share corners with four equivalent C(1)Y4Mo2 octahedra, corners with nine equivalent C(2)Y3Mo3 octahedra, edges with two equivalent C(1)Y4Mo2 octahedra, edges with three equivalent C(2)Y3Mo3 octahedra,  a faceface with one C(2)Y3Mo3 octahedra, and faces with two equivalent C(1)Y4Mo2 octahedra. The corner-sharing octahedral tilt angles range from 10-60°. In the second C site, C(2) is bonded to three equivalent Y(1) and three equivalent Mo(1) atoms to form CY3Mo3 octahedra that share corners with nine equivalent C(1)Y4Mo2 octahedra, edges with three equivalent C(1)Y4Mo2 octahedra, edges with six equivalent C(2)Y3Mo3 octahedra, and  a faceface with one C(1)Y4Mo2 octahedra. The corner-sharing octahedral tilt angles range from 10-60°.
YMoC2 crystallizes in the orthorhombic Pnma space group. Y(1) is bonded to three equivalent C(2) and four equivalent C(1) atoms to form distorted YC7 pentagonal bipyramids that share corners with four equivalent Y(1)C7 pentagonal bipyramids, corners with three equivalent Mo(1)C5 trigonal bipyramids, edges with four equivalent Y(1)C7 pentagonal bipyramids, edges with seven equivalent Mo(1)C5 trigonal bipyramids, and faces with two equivalent Y(1)C7 pentagonal bipyramids. There is one shorter (2.45 Å) and two longer (2.63 Å) Y(1)-C(2) bond lengths. There are two shorter (2.49 Å) and two longer (2.56 Å) Y(1)-C(1) bond lengths. Mo(1) is bonded to two equivalent C(1) and three equivalent C(2) atoms to form MoC5 trigonal bipyramids that share corners with three equivalent Y(1)C7 pentagonal bipyramids, corners with four equivalent Mo(1)C5 trigonal bipyramids, edges with seven equivalent Y(1)C7 pentagonal bipyramids, and edges with two equivalent Mo(1)C5 trigonal bipyramids. There is one shorter (2.03 Å) and one longer (2.12 Å) Mo(1)-C(1) bond length. There are two shorter (2.09 Å) and one longer (2.28 Å) Mo(1)-C(2) bond length. There are two inequivalent C sites. In the first C site, C(1) is bonded to four equivalent Y(1) and two equivalent Mo(1) atoms to form CY4Mo2 octahedra that share corners with four equivalent C(1)Y4Mo2 octahedra, corners with nine equivalent C(2)Y3Mo3 octahedra, edges with two equivalent C(1)Y4Mo2 octahedra, edges with three equivalent C(2)Y3Mo3 octahedra,  a faceface with one C(2)Y3Mo3 octahedra, and faces with two equivalent C(1)Y4Mo2 octahedra. The corner-sharing octahedral tilt angles range from 10-60°. In the second C site, C(2) is bonded to three equivalent Y(1) and three equivalent Mo(1) atoms to form CY3Mo3 octahedra that share corners with nine equivalent C(1)Y4Mo2 octahedra, edges with three equivalent C(1)Y4Mo2 octahedra, edges with six equivalent C(2)Y3Mo3 octahedra, and  a faceface with one C(1)Y4Mo2 octahedra. The corner-sharing octahedral tilt angles range from 10-60°.