UNiAs crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 12-coordinate geometry to six equivalent Ni(1) and six equivalent As(1) atoms. In the second U site, U(2) is bonded to six equivalent As(1) atoms to form distorted edge-sharing UAs6 octahedra. Ni(1) is bonded in a 6-coordinate geometry to three equivalent U(1) and three equivalent As(1) atoms. As(1) is bonded in a 9-coordinate geometry to three equivalent U(1), three equivalent U(2), and three equivalent Ni(1) atoms.
UNiAs crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 12-coordinate geometry to six equivalent Ni(1) and six equivalent As(1) atoms. All U(1)-Ni(1) bond lengths are 2.78 Å. All U(1)-As(1) bond lengths are 3.11 Å. In the second U site, U(2) is bonded to six equivalent As(1) atoms to form distorted edge-sharing UAs6 octahedra. All U(2)-As(1) bond lengths are 2.99 Å. Ni(1) is bonded in a 6-coordinate geometry to three equivalent U(1) and three equivalent As(1) atoms. All Ni(1)-As(1) bond lengths are 2.41 Å. As(1) is bonded in a 9-coordinate geometry to three equivalent U(1), three equivalent U(2), and three equivalent Ni(1) atoms.