TmNiAs is hexagonal omega structure-derived structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to six equivalent Ni(1) and six equivalent As(1) atoms to form a mixture of edge and face-sharing TmNi6As6 cuboctahedra. In the second Tm site, Tm(2) is bonded to six equivalent Ni(1) and six equivalent As(1) atoms to form a mixture of edge and face-sharing TmNi6As6 cuboctahedra. Ni(1) is bonded in a 9-coordinate geometry to three equivalent Tm(1), three equivalent Tm(2), and three equivalent As(1) atoms. As(1) is bonded in a 9-coordinate geometry to three equivalent Tm(1), three equivalent Tm(2), and three equivalent Ni(1) atoms.
TmNiAs is hexagonal omega structure-derived structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to six equivalent Ni(1) and six equivalent As(1) atoms to form a mixture of edge and face-sharing TmNi6As6 cuboctahedra. All Tm(1)-Ni(1) bond lengths are 2.88 Å. All Tm(1)-As(1) bond lengths are 3.02 Å. In the second Tm site, Tm(2) is bonded to six equivalent Ni(1) and six equivalent As(1) atoms to form a mixture of edge and face-sharing TmNi6As6 cuboctahedra. All Tm(2)-Ni(1) bond lengths are 3.08 Å. All Tm(2)-As(1) bond lengths are 2.93 Å. Ni(1) is bonded in a 9-coordinate geometry to three equivalent Tm(1), three equivalent Tm(2), and three equivalent As(1) atoms. All Ni(1)-As(1) bond lengths are 2.32 Å. As(1) is bonded in a 9-coordinate geometry to three equivalent Tm(1), three equivalent Tm(2), and three equivalent Ni(1) atoms.