Y2Ni12As7 crystallizes in the hexagonal P-6 space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a 18-coordinate geometry to three equivalent Ni(1), three equivalent Ni(2), six equivalent Ni(3), and six equivalent As(2) atoms. In the second Y site, Y(2) is bonded in a 15-coordinate geometry to three equivalent Ni(3), six equivalent Ni(1), and six equivalent As(1) atoms. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one Y(1), two equivalent Y(2), two equivalent As(1), and two equivalent As(2) atoms to form distorted NiY3As4 tetrahedra that share corners with four equivalent Ni(3)Y3As4 tetrahedra, corners with four equivalent Ni(2)YAs4 tetrahedra, corners with six equivalent Ni(1)Y3As4 tetrahedra,  an edgeedge with one Ni(2)YAs4 tetrahedra, edges with two equivalent Ni(1)Y3As4 tetrahedra, edges with four equivalent Ni(3)Y3As4 tetrahedra,  a faceface with one Ni(2)YAs4 tetrahedra, faces with two equivalent Ni(1)Y3As4 tetrahedra, and faces with two equivalent Ni(3)Y3As4 tetrahedra. In the second Ni site, Ni(2) is bonded to one Y(1), one As(1), one As(3), and two equivalent As(2) atoms to form distorted NiYAs4 tetrahedra that share corners with two equivalent Ni(3)Y3As4 tetrahedra, corners with four equivalent Ni(1)Y3As4 tetrahedra, corners with six equivalent Ni(2)YAs4 tetrahedra,  an edgeedge with one Ni(1)Y3As4 tetrahedra, edges with two equivalent Ni(3)Y3As4 tetrahedra,  a faceface with one Ni(1)Y3As4 tetrahedra, and faces with two equivalent Ni(3)Y3As4 tetrahedra. In the third Ni site, Ni(3) is bonded to one Y(2), two equivalent Y(1), two equivalent As(1), and two equivalent As(2) atoms to form distorted NiY3As4 tetrahedra that share corners with two equivalent Ni(2)YAs4 tetrahedra, corners with four equivalent Ni(1)Y3As4 tetrahedra, corners with six equivalent Ni(3)Y3As4 tetrahedra, edges with two equivalent Ni(3)Y3As4 tetrahedra, edges with two equivalent Ni(2)YAs4 tetrahedra, edges with four equivalent Ni(1)Y3As4 tetrahedra, faces with two equivalent Ni(1)Y3As4 tetrahedra, faces with two equivalent Ni(3)Y3As4 tetrahedra, and faces with two equivalent Ni(2)YAs4 tetrahedra. In the fourth Ni site, Ni(4) is bonded in a 5-coordinate geometry to one As(2), two equivalent As(1), and two equivalent As(3) atoms. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 9-coordinate geometry to two equivalent Y(2), one Ni(2), two equivalent Ni(1), two equivalent Ni(3), and two equivalent Ni(4) atoms. In the second As site, As(2) is bonded in a 9-coordinate geometry to two equivalent Y(1), one Ni(4), two equivalent Ni(1), two equivalent Ni(2), and two equivalent Ni(3) atoms. In the third As site, As(3) is bonded in a 9-coordinate geometry to three equivalent Ni(2) and six equivalent Ni(4) atoms.
Y2Ni12As7 crystallizes in the hexagonal P-6 space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a 18-coordinate geometry to three equivalent Ni(1), three equivalent Ni(2), six equivalent Ni(3), and six equivalent As(2) atoms. All Y(1)-Ni(1) bond lengths are 3.26 Å. All Y(1)-Ni(2) bond lengths are 3.14 Å. All Y(1)-Ni(3) bond lengths are 3.14 Å. All Y(1)-As(2) bond lengths are 2.98 Å. In the second Y site, Y(2) is bonded in a 15-coordinate geometry to three equivalent Ni(3), six equivalent Ni(1), and six equivalent As(1) atoms. All Y(2)-Ni(3) bond lengths are 3.21 Å. All Y(2)-Ni(1) bond lengths are 3.08 Å. All Y(2)-As(1) bond lengths are 2.97 Å. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one Y(1), two equivalent Y(2), two equivalent As(1), and two equivalent As(2) atoms to form distorted NiY3As4 tetrahedra that share corners with four equivalent Ni(3)Y3As4 tetrahedra, corners with four equivalent Ni(2)YAs4 tetrahedra, corners with six equivalent Ni(1)Y3As4 tetrahedra,  an edgeedge with one Ni(2)YAs4 tetrahedra, edges with two equivalent Ni(1)Y3As4 tetrahedra, edges with four equivalent Ni(3)Y3As4 tetrahedra,  a faceface with one Ni(2)YAs4 tetrahedra, faces with two equivalent Ni(1)Y3As4 tetrahedra, and faces with two equivalent Ni(3)Y3As4 tetrahedra. There is one shorter (2.33 Å) and one longer (2.35 Å) Ni(1)-As(1) bond length. Both Ni(1)-As(2) bond lengths are 2.40 Å. In the second Ni site, Ni(2) is bonded to one Y(1), one As(1), one As(3), and two equivalent As(2) atoms to form distorted NiYAs4 tetrahedra that share corners with two equivalent Ni(3)Y3As4 tetrahedra, corners with four equivalent Ni(1)Y3As4 tetrahedra, corners with six equivalent Ni(2)YAs4 tetrahedra,  an edgeedge with one Ni(1)Y3As4 tetrahedra, edges with two equivalent Ni(3)Y3As4 tetrahedra,  a faceface with one Ni(1)Y3As4 tetrahedra, and faces with two equivalent Ni(3)Y3As4 tetrahedra. The Ni(2)-As(1) bond length is 2.32 Å. The Ni(2)-As(3) bond length is 2.26 Å. Both Ni(2)-As(2) bond lengths are 2.39 Å. In the third Ni site, Ni(3) is bonded to one Y(2), two equivalent Y(1), two equivalent As(1), and two equivalent As(2) atoms to form distorted NiY3As4 tetrahedra that share corners with two equivalent Ni(2)YAs4 tetrahedra, corners with four equivalent Ni(1)Y3As4 tetrahedra, corners with six equivalent Ni(3)Y3As4 tetrahedra, edges with two equivalent Ni(3)Y3As4 tetrahedra, edges with two equivalent Ni(2)YAs4 tetrahedra, edges with four equivalent Ni(1)Y3As4 tetrahedra, faces with two equivalent Ni(1)Y3As4 tetrahedra, faces with two equivalent Ni(3)Y3As4 tetrahedra, and faces with two equivalent Ni(2)YAs4 tetrahedra. Both Ni(3)-As(1) bond lengths are 2.39 Å. There is one shorter (2.36 Å) and one longer (2.43 Å) Ni(3)-As(2) bond length. In the fourth Ni site, Ni(4) is bonded in a 5-coordinate geometry to one As(2), two equivalent As(1), and two equivalent As(3) atoms. The Ni(4)-As(2) bond length is 2.42 Å. Both Ni(4)-As(1) bond lengths are 2.63 Å. Both Ni(4)-As(3) bond lengths are 2.57 Å. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 9-coordinate geometry to two equivalent Y(2), one Ni(2), two equivalent Ni(1), two equivalent Ni(3), and two equivalent Ni(4) atoms. In the second As site, As(2) is bonded in a 9-coordinate geometry to two equivalent Y(1), one Ni(4), two equivalent Ni(1), two equivalent Ni(2), and two equivalent Ni(3) atoms. In the third As site, As(3) is bonded in a 9-coordinate geometry to three equivalent Ni(2) and six equivalent Ni(4) atoms.