YH3 crystallizes in the hexagonal P6_3/mmc space group. Y(1) is bonded in a 14-coordinate geometry to six equivalent H(1) and eight equivalent H(2) atoms. There are two inequivalent H sites. In the first H site, H(1) is bonded to six equivalent Y(1) atoms to form HY6 octahedra that share corners with twelve equivalent H(1)Y6 octahedra, corners with eighteen equivalent H(2)Y4 tetrahedra, edges with six equivalent H(1)Y6 octahedra, edges with six equivalent H(2)Y4 tetrahedra, faces with two equivalent H(1)Y6 octahedra, and faces with six equivalent H(2)Y4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. In the second H site, H(2) is bonded to four equivalent Y(1) atoms to form HY4 tetrahedra that share corners with nine equivalent H(1)Y6 octahedra, corners with nineteen equivalent H(2)Y4 tetrahedra, edges with three equivalent H(1)Y6 octahedra, edges with three equivalent H(2)Y4 tetrahedra, faces with three equivalent H(1)Y6 octahedra, and  a faceface with one H(2)Y4 tetrahedra. The corner-sharing octahedral tilt angles range from 12-60°.
YH3 crystallizes in the hexagonal P6_3/mmc space group. Y(1) is bonded in a 14-coordinate geometry to six equivalent H(1) and eight equivalent H(2) atoms. All Y(1)-H(1) bond lengths are 2.59 Å. There are two shorter (2.13 Å) and six longer (2.29 Å) Y(1)-H(2) bond lengths. There are two inequivalent H sites. In the first H site, H(1) is bonded to six equivalent Y(1) atoms to form HY6 octahedra that share corners with twelve equivalent H(1)Y6 octahedra, corners with eighteen equivalent H(2)Y4 tetrahedra, edges with six equivalent H(1)Y6 octahedra, edges with six equivalent H(2)Y4 tetrahedra, faces with two equivalent H(1)Y6 octahedra, and faces with six equivalent H(2)Y4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. In the second H site, H(2) is bonded to four equivalent Y(1) atoms to form HY4 tetrahedra that share corners with nine equivalent H(1)Y6 octahedra, corners with nineteen equivalent H(2)Y4 tetrahedra, edges with three equivalent H(1)Y6 octahedra, edges with three equivalent H(2)Y4 tetrahedra, faces with three equivalent H(1)Y6 octahedra, and  a faceface with one H(2)Y4 tetrahedra. The corner-sharing octahedral tilt angles range from 12-60°.