Li4NiSi2O7 is Stannite-like structured and crystallizes in the monoclinic C2 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(7), and two equivalent O(5) atoms to form LiO4 tetrahedra that share  a cornercorner with one Ni(1)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Li(3)O4 tetrahedra, and corners with five equivalent Si(1)O4 tetrahedra. In the second Li site, Li(2) is bonded to one O(2), one O(8), and two equivalent O(6) atoms to form LiO4 tetrahedra that share  a cornercorner with one Ni(1)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, corners with three equivalent Li(4)O4 tetrahedra, and corners with five equivalent Si(2)O4 tetrahedra. In the third Li site, Li(3) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form LiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Ni(1)O4 tetrahedra, and corners with three equivalent Si(1)O4 tetrahedra. In the fourth Li site, Li(4) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form LiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, corners with three equivalent Ni(1)O4 tetrahedra, and corners with three equivalent Si(2)O4 tetrahedra. Ni(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form distorted NiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with three equivalent Li(3)O4 tetrahedra, and corners with three equivalent Li(4)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, corners with three equivalent Li(3)O4 tetrahedra, and corners with five equivalent Li(1)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, corners with three equivalent Li(4)O4 tetrahedra, and corners with five equivalent Li(2)O4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(5) is bonded to one Li(3), two equivalent Li(1), and one Si(1) atom to form OLi3Si tetrahedra that share  a cornercorner with one O(4)Li2SiNi tetrahedra, corners with two equivalent O(3)Li2SiNi tetrahedra, corners with two equivalent O(5)Li3Si tetrahedra, corners with three equivalent O(7)Li2Si2 tetrahedra, and corners with four equivalent O(1)Li2SiNi tetrahedra. In the second O site, O(6) is bonded to one Li(4), two equivalent Li(2), and one Si(2) atom to form OLi3Si tetrahedra that share  a cornercorner with one O(3)Li2SiNi tetrahedra, corners with two equivalent O(4)Li2SiNi tetrahedra, corners with two equivalent O(6)Li3Si tetrahedra, corners with three equivalent O(8)Li2Si2 tetrahedra, and corners with four equivalent O(2)Li2SiNi tetrahedra. In the third O site, O(7) is bonded to two equivalent Li(1) and two equivalent Si(1) atoms to form OLi2Si2 tetrahedra that share corners with two equivalent O(3)Li2SiNi tetrahedra, corners with four equivalent O(1)Li2SiNi tetrahedra, and corners with six equivalent O(5)Li3Si tetrahedra. In the fourth O site, O(8) is bonded to two equivalent Li(2) and two equivalent Si(2) atoms to form OLi2Si2 tetrahedra that share corners with two equivalent O(4)Li2SiNi tetrahedra, corners with four equivalent O(2)Li2SiNi tetrahedra, and corners with six equivalent O(6)Li3Si tetrahedra. In the fifth O site, O(1) is bonded to one Li(1), one Li(3), one Ni(1), and one Si(1) atom to form distorted OLi2SiNi tetrahedra that share  a cornercorner with one O(2)Li2SiNi tetrahedra, corners with two equivalent O(7)Li2Si2 tetrahedra, corners with two equivalent O(4)Li2SiNi tetrahedra, corners with three equivalent O(3)Li2SiNi tetrahedra, and corners with four equivalent O(5)Li3Si tetrahedra. In the sixth O site, O(2) is bonded to one Li(2), one Li(4), one Ni(1), and one Si(2) atom to form OLi2SiNi tetrahedra that share  a cornercorner with one O(1)Li2SiNi tetrahedra, corners with two equivalent O(8)Li2Si2 tetrahedra, corners with two equivalent O(3)Li2SiNi tetrahedra, corners with three equivalent O(4)Li2SiNi tetrahedra, and corners with four equivalent O(6)Li3Si tetrahedra. In the seventh O site, O(3) is bonded to one Li(3), one Li(4), one Ni(1), and one Si(1) atom to form OLi2SiNi tetrahedra that share  a cornercorner with one O(7)Li2Si2 tetrahedra,  a cornercorner with one O(6)Li3Si tetrahedra, corners with two equivalent O(2)Li2SiNi tetrahedra, corners with two equivalent O(5)Li3Si tetrahedra, corners with three equivalent O(1)Li2SiNi tetrahedra, and corners with three equivalent O(4)Li2SiNi tetrahedra. In the eighth O site, O(4) is bonded to one Li(3), one Li(4), one Ni(1), and one Si(2) atom to form distorted OLi2SiNi tetrahedra that share  a cornercorner with one O(8)Li2Si2 tetrahedra,  a cornercorner with one O(5)Li3Si tetrahedra, corners with two equivalent O(1)Li2SiNi tetrahedra, corners with two equivalent O(6)Li3Si tetrahedra, corners with three equivalent O(2)Li2SiNi tetrahedra, and corners with three equivalent O(3)Li2SiNi tetrahedra.
Li4NiSi2O7 is Stannite-like structured and crystallizes in the monoclinic C2 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(7), and two equivalent O(5) atoms to form LiO4 tetrahedra that share  a cornercorner with one Ni(1)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Li(3)O4 tetrahedra, and corners with five equivalent Si(1)O4 tetrahedra. The Li(1)-O(1) bond length is 1.97 Å. The Li(1)-O(7) bond length is 2.16 Å. There is one shorter (1.93 Å) and one longer (1.95 Å) Li(1)-O(5) bond length. In the second Li site, Li(2) is bonded to one O(2), one O(8), and two equivalent O(6) atoms to form LiO4 tetrahedra that share  a cornercorner with one Ni(1)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, corners with three equivalent Li(4)O4 tetrahedra, and corners with five equivalent Si(2)O4 tetrahedra. The Li(2)-O(2) bond length is 1.98 Å. The Li(2)-O(8) bond length is 2.17 Å. There is one shorter (1.93 Å) and one longer (1.95 Å) Li(2)-O(6) bond length. In the third Li site, Li(3) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form LiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Ni(1)O4 tetrahedra, and corners with three equivalent Si(1)O4 tetrahedra. The Li(3)-O(1) bond length is 2.02 Å. The Li(3)-O(3) bond length is 1.98 Å. The Li(3)-O(4) bond length is 2.03 Å. The Li(3)-O(5) bond length is 1.94 Å. In the fourth Li site, Li(4) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form LiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, corners with three equivalent Ni(1)O4 tetrahedra, and corners with three equivalent Si(2)O4 tetrahedra. The Li(4)-O(2) bond length is 1.97 Å. The Li(4)-O(3) bond length is 2.08 Å. The Li(4)-O(4) bond length is 2.02 Å. The Li(4)-O(6) bond length is 1.93 Å. Ni(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form distorted NiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with three equivalent Li(3)O4 tetrahedra, and corners with three equivalent Li(4)O4 tetrahedra. The Ni(1)-O(1) bond length is 1.98 Å. The Ni(1)-O(2) bond length is 1.99 Å. The Ni(1)-O(3) bond length is 2.00 Å. The Ni(1)-O(4) bond length is 1.98 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, corners with three equivalent Li(3)O4 tetrahedra, and corners with five equivalent Li(1)O4 tetrahedra. The Si(1)-O(1) bond length is 1.64 Å. The Si(1)-O(3) bond length is 1.64 Å. The Si(1)-O(5) bond length is 1.62 Å. The Si(1)-O(7) bond length is 1.72 Å. In the second Si site, Si(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra, corners with three equivalent Li(4)O4 tetrahedra, and corners with five equivalent Li(2)O4 tetrahedra. The Si(2)-O(2) bond length is 1.65 Å. The Si(2)-O(4) bond length is 1.64 Å. The Si(2)-O(6) bond length is 1.62 Å. The Si(2)-O(8) bond length is 1.72 Å. There are eight inequivalent O sites. In the first O site, O(5) is bonded to one Li(3), two equivalent Li(1), and one Si(1) atom to form OLi3Si tetrahedra that share  a cornercorner with one O(4)Li2SiNi tetrahedra, corners with two equivalent O(3)Li2SiNi tetrahedra, corners with two equivalent O(5)Li3Si tetrahedra, corners with three equivalent O(7)Li2Si2 tetrahedra, and corners with four equivalent O(1)Li2SiNi tetrahedra. In the second O site, O(6) is bonded to one Li(4), two equivalent Li(2), and one Si(2) atom to form OLi3Si tetrahedra that share  a cornercorner with one O(3)Li2SiNi tetrahedra, corners with two equivalent O(4)Li2SiNi tetrahedra, corners with two equivalent O(6)Li3Si tetrahedra, corners with three equivalent O(8)Li2Si2 tetrahedra, and corners with four equivalent O(2)Li2SiNi tetrahedra. In the third O site, O(7) is bonded to two equivalent Li(1) and two equivalent Si(1) atoms to form OLi2Si2 tetrahedra that share corners with two equivalent O(3)Li2SiNi tetrahedra, corners with four equivalent O(1)Li2SiNi tetrahedra, and corners with six equivalent O(5)Li3Si tetrahedra. In the fourth O site, O(8) is bonded to two equivalent Li(2) and two equivalent Si(2) atoms to form OLi2Si2 tetrahedra that share corners with two equivalent O(4)Li2SiNi tetrahedra, corners with four equivalent O(2)Li2SiNi tetrahedra, and corners with six equivalent O(6)Li3Si tetrahedra. In the fifth O site, O(1) is bonded to one Li(1), one Li(3), one Ni(1), and one Si(1) atom to form distorted OLi2SiNi tetrahedra that share  a cornercorner with one O(2)Li2SiNi tetrahedra, corners with two equivalent O(7)Li2Si2 tetrahedra, corners with two equivalent O(4)Li2SiNi tetrahedra, corners with three equivalent O(3)Li2SiNi tetrahedra, and corners with four equivalent O(5)Li3Si tetrahedra. In the sixth O site, O(2) is bonded to one Li(2), one Li(4), one Ni(1), and one Si(2) atom to form OLi2SiNi tetrahedra that share  a cornercorner with one O(1)Li2SiNi tetrahedra, corners with two equivalent O(8)Li2Si2 tetrahedra, corners with two equivalent O(3)Li2SiNi tetrahedra, corners with three equivalent O(4)Li2SiNi tetrahedra, and corners with four equivalent O(6)Li3Si tetrahedra. In the seventh O site, O(3) is bonded to one Li(3), one Li(4), one Ni(1), and one Si(1) atom to form OLi2SiNi tetrahedra that share  a cornercorner with one O(7)Li2Si2 tetrahedra,  a cornercorner with one O(6)Li3Si tetrahedra, corners with two equivalent O(2)Li2SiNi tetrahedra, corners with two equivalent O(5)Li3Si tetrahedra, corners with three equivalent O(1)Li2SiNi tetrahedra, and corners with three equivalent O(4)Li2SiNi tetrahedra. In the eighth O site, O(4) is bonded to one Li(3), one Li(4), one Ni(1), and one Si(2) atom to form distorted OLi2SiNi tetrahedra that share  a cornercorner with one O(8)Li2Si2 tetrahedra,  a cornercorner with one O(5)Li3Si tetrahedra, corners with two equivalent O(1)Li2SiNi tetrahedra, corners with two equivalent O(6)Li3Si tetrahedra, corners with three equivalent O(2)Li2SiNi tetrahedra, and corners with three equivalent O(3)Li2SiNi tetrahedra.