ErCuZnP2 crystallizes in the trigonal P3m1 space group. Er(1) is bonded to three equivalent P(1) and three equivalent P(2) atoms to form distorted ErP6 octahedra that share corners with six equivalent Cu(1)P4 tetrahedra, corners with six equivalent Zn(1)P4 tetrahedra, edges with six equivalent Er(1)P6 octahedra, edges with three equivalent Cu(1)P4 tetrahedra, and edges with three equivalent Zn(1)P4 tetrahedra. Cu(1) is bonded to one P(1) and three equivalent P(2) atoms to form distorted CuP4 tetrahedra that share corners with six equivalent Er(1)P6 octahedra, corners with six equivalent Cu(1)P4 tetrahedra, edges with three equivalent Er(1)P6 octahedra, and edges with three equivalent Zn(1)P4 tetrahedra. The corner-sharing octahedral tilt angles range from 16-53°. Zn(1) is bonded to one P(2) and three equivalent P(1) atoms to form distorted ZnP4 tetrahedra that share corners with six equivalent Er(1)P6 octahedra, corners with six equivalent Zn(1)P4 tetrahedra, edges with three equivalent Er(1)P6 octahedra, and edges with three equivalent Cu(1)P4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-56°. There are two inequivalent P sites. In the first P site, P(1) is bonded to three equivalent Er(1), one Cu(1), and three equivalent Zn(1) atoms to form distorted PEr3Zn3Cu pentagonal bipyramids that share corners with three equivalent P(2)Er3ZnCu3 pentagonal bipyramids, edges with six equivalent P(1)Er3Zn3Cu pentagonal bipyramids, and edges with six equivalent P(2)Er3ZnCu3 pentagonal bipyramids. In the second P site, P(2) is bonded to three equivalent Er(1), three equivalent Cu(1), and one Zn(1) atom to form distorted PEr3ZnCu3 pentagonal bipyramids that share corners with three equivalent P(1)Er3Zn3Cu pentagonal bipyramids, edges with six equivalent P(1)Er3Zn3Cu pentagonal bipyramids, and edges with six equivalent P(2)Er3ZnCu3 pentagonal bipyramids.
ErCuZnP2 crystallizes in the trigonal P3m1 space group. Er(1) is bonded to three equivalent P(1) and three equivalent P(2) atoms to form distorted ErP6 octahedra that share corners with six equivalent Cu(1)P4 tetrahedra, corners with six equivalent Zn(1)P4 tetrahedra, edges with six equivalent Er(1)P6 octahedra, edges with three equivalent Cu(1)P4 tetrahedra, and edges with three equivalent Zn(1)P4 tetrahedra. All Er(1)-P(1) bond lengths are 2.88 Å. All Er(1)-P(2) bond lengths are 2.75 Å. Cu(1) is bonded to one P(1) and three equivalent P(2) atoms to form distorted CuP4 tetrahedra that share corners with six equivalent Er(1)P6 octahedra, corners with six equivalent Cu(1)P4 tetrahedra, edges with three equivalent Er(1)P6 octahedra, and edges with three equivalent Zn(1)P4 tetrahedra. The corner-sharing octahedral tilt angles range from 16-53°. The Cu(1)-P(1) bond length is 2.51 Å. All Cu(1)-P(2) bond lengths are 2.40 Å. Zn(1) is bonded to one P(2) and three equivalent P(1) atoms to form distorted ZnP4 tetrahedra that share corners with six equivalent Er(1)P6 octahedra, corners with six equivalent Zn(1)P4 tetrahedra, edges with three equivalent Er(1)P6 octahedra, and edges with three equivalent Cu(1)P4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-56°. The Zn(1)-P(2) bond length is 2.42 Å. All Zn(1)-P(1) bond lengths are 2.42 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to three equivalent Er(1), one Cu(1), and three equivalent Zn(1) atoms to form distorted PEr3Zn3Cu pentagonal bipyramids that share corners with three equivalent P(2)Er3ZnCu3 pentagonal bipyramids, edges with six equivalent P(1)Er3Zn3Cu pentagonal bipyramids, and edges with six equivalent P(2)Er3ZnCu3 pentagonal bipyramids. In the second P site, P(2) is bonded to three equivalent Er(1), three equivalent Cu(1), and one Zn(1) atom to form distorted PEr3ZnCu3 pentagonal bipyramids that share corners with three equivalent P(1)Er3Zn3Cu pentagonal bipyramids, edges with six equivalent P(1)Er3Zn3Cu pentagonal bipyramids, and edges with six equivalent P(2)Er3ZnCu3 pentagonal bipyramids.