BaNi9As5 crystallizes in the hexagonal P6_3/mmc space group. Ba(1) is bonded in a 18-coordinate geometry to twelve equivalent Ni(1) and six equivalent As(1) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent As(1), and two equivalent As(2) atoms. In the second Ni site, Ni(2) is bonded in a 2-coordinate geometry to two equivalent As(1) and two equivalent As(2) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Ni(2), and four equivalent Ni(1) atoms. In the second As site, As(2) is bonded in a distorted q6 geometry to three equivalent Ni(2) and six equivalent Ni(1) atoms.
BaNi9As5 crystallizes in the hexagonal P6_3/mmc space group. Ba(1) is bonded in a 18-coordinate geometry to twelve equivalent Ni(1) and six equivalent As(1) atoms. All Ba(1)-Ni(1) bond lengths are 3.58 Å. All Ba(1)-As(1) bond lengths are 3.45 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent As(1), and two equivalent As(2) atoms. Both Ni(1)-As(1) bond lengths are 2.35 Å. There is one shorter (2.40 Å) and one longer (2.41 Å) Ni(1)-As(2) bond length. In the second Ni site, Ni(2) is bonded in a 2-coordinate geometry to two equivalent As(1) and two equivalent As(2) atoms. Both Ni(2)-As(1) bond lengths are 2.25 Å. Both Ni(2)-As(2) bond lengths are 2.57 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Ni(2), and four equivalent Ni(1) atoms. In the second As site, As(2) is bonded in a distorted q6 geometry to three equivalent Ni(2) and six equivalent Ni(1) atoms.