Li2NiSi2O6 crystallizes in the triclinic P1 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(10), one O(4), one O(5), and one O(6) atom to form LiO4 tetrahedra that share  a cornercorner with one Ni(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. In the second Li site, Li(2) is bonded to one O(3), one O(5), one O(6), and one O(9) atom to form LiO4 tetrahedra that share  a cornercorner with one Ni(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Ni(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. In the third Li site, Li(3) is bonded to one O(12), one O(2), one O(7), and one O(8) atom to form LiO4 tetrahedra that share  a cornercorner with one Ni(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Ni(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. In the fourth Li site, Li(4) is bonded to one O(1), one O(11), one O(7), and one O(8) atom to form LiO4 tetrahedra that share  a cornercorner with one Ni(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(4), one O(5), and one O(8) atom to form NiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(3)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. In the second Ni site, Ni(2) is bonded to one O(2), one O(3), one O(6), and one O(7) atom to form NiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(4)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(10), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(4)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(10), one O(2), one O(6), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(3)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Ni(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(11), one O(12), one O(3), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Ni(2)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(11), one O(12), one O(4), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(4), one Ni(1), and one Si(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Li(3), one Ni(2), and one Si(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(2), one Ni(2), and one Si(3) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Li(1), one Ni(1), and one Si(4) atom. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one Ni(1), and one Si(1) atom to form corner-sharing OLi2SiNi tetrahedra. In the sixth O site, O(6) is bonded to one Li(1), one Li(2), one Ni(2), and one Si(2) atom to form corner-sharing OLi2SiNi tetrahedra. In the seventh O site, O(7) is bonded to one Li(3), one Li(4), one Ni(2), and one Si(3) atom to form corner-sharing OLi2SiNi tetrahedra. In the eighth O site, O(8) is bonded to one Li(3), one Li(4), one Ni(1), and one Si(4) atom to form corner-sharing OLi2SiNi tetrahedra. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Li(2), one Si(1), and one Si(2) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Li(1), one Si(1), and one Si(2) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Li(4), one Si(3), and one Si(4) atom. In the twelfth O site, O(12) is bonded in a trigonal planar geometry to one Li(3), one Si(3), and one Si(4) atom.
Li2NiSi2O6 crystallizes in the triclinic P1 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(10), one O(4), one O(5), and one O(6) atom to form LiO4 tetrahedra that share  a cornercorner with one Ni(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The Li(1)-O(10) bond length is 2.13 Å. The Li(1)-O(4) bond length is 1.91 Å. The Li(1)-O(5) bond length is 2.00 Å. The Li(1)-O(6) bond length is 1.97 Å. In the second Li site, Li(2) is bonded to one O(3), one O(5), one O(6), and one O(9) atom to form LiO4 tetrahedra that share  a cornercorner with one Ni(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Ni(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The Li(2)-O(3) bond length is 1.95 Å. The Li(2)-O(5) bond length is 1.98 Å. The Li(2)-O(6) bond length is 2.02 Å. The Li(2)-O(9) bond length is 2.14 Å. In the third Li site, Li(3) is bonded to one O(12), one O(2), one O(7), and one O(8) atom to form LiO4 tetrahedra that share  a cornercorner with one Ni(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Ni(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. The Li(3)-O(12) bond length is 2.14 Å. The Li(3)-O(2) bond length is 1.95 Å. The Li(3)-O(7) bond length is 2.02 Å. The Li(3)-O(8) bond length is 1.98 Å. In the fourth Li site, Li(4) is bonded to one O(1), one O(11), one O(7), and one O(8) atom to form LiO4 tetrahedra that share  a cornercorner with one Ni(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. The Li(4)-O(1) bond length is 1.91 Å. The Li(4)-O(11) bond length is 2.13 Å. The Li(4)-O(7) bond length is 1.97 Å. The Li(4)-O(8) bond length is 2.01 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(4), one O(5), and one O(8) atom to form NiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(3)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. The Ni(1)-O(1) bond length is 1.94 Å. The Ni(1)-O(4) bond length is 1.94 Å. The Ni(1)-O(5) bond length is 2.01 Å. The Ni(1)-O(8) bond length is 2.01 Å. In the second Ni site, Ni(2) is bonded to one O(2), one O(3), one O(6), and one O(7) atom to form NiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(4)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The Ni(2)-O(2) bond length is 1.96 Å. The Ni(2)-O(3) bond length is 1.96 Å. The Ni(2)-O(6) bond length is 2.01 Å. The Ni(2)-O(7) bond length is 2.01 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(10), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(4)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The Si(1)-O(1) bond length is 1.62 Å. The Si(1)-O(10) bond length is 1.67 Å. The Si(1)-O(5) bond length is 1.63 Å. The Si(1)-O(9) bond length is 1.68 Å. In the second Si site, Si(2) is bonded to one O(10), one O(2), one O(6), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(3)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Ni(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The Si(2)-O(10) bond length is 1.67 Å. The Si(2)-O(2) bond length is 1.62 Å. The Si(2)-O(6) bond length is 1.63 Å. The Si(2)-O(9) bond length is 1.67 Å. In the third Si site, Si(3) is bonded to one O(11), one O(12), one O(3), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Ni(2)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. The Si(3)-O(11) bond length is 1.67 Å. The Si(3)-O(12) bond length is 1.67 Å. The Si(3)-O(3) bond length is 1.62 Å. The Si(3)-O(7) bond length is 1.63 Å. In the fourth Si site, Si(4) is bonded to one O(11), one O(12), one O(4), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The Si(4)-O(11) bond length is 1.67 Å. The Si(4)-O(12) bond length is 1.68 Å. The Si(4)-O(4) bond length is 1.62 Å. The Si(4)-O(8) bond length is 1.63 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(4), one Ni(1), and one Si(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Li(3), one Ni(2), and one Si(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(2), one Ni(2), and one Si(3) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Li(1), one Ni(1), and one Si(4) atom. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one Ni(1), and one Si(1) atom to form corner-sharing OLi2SiNi tetrahedra. In the sixth O site, O(6) is bonded to one Li(1), one Li(2), one Ni(2), and one Si(2) atom to form corner-sharing OLi2SiNi tetrahedra. In the seventh O site, O(7) is bonded to one Li(3), one Li(4), one Ni(2), and one Si(3) atom to form corner-sharing OLi2SiNi tetrahedra. In the eighth O site, O(8) is bonded to one Li(3), one Li(4), one Ni(1), and one Si(4) atom to form corner-sharing OLi2SiNi tetrahedra. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Li(2), one Si(1), and one Si(2) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Li(1), one Si(1), and one Si(2) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Li(4), one Si(3), and one Si(4) atom. In the twelfth O site, O(12) is bonded in a trigonal planar geometry to one Li(3), one Si(3), and one Si(4) atom.