The compound described by 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. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li4Si2NiO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.510
_cell_length_b   5.316
_cell_length_c   6.771
_cell_angle_alpha   80.989
_cell_angle_beta   89.964
_cell_angle_gamma   64.908
_symmetry_Int_Tables_number   1
_cell_volume   144.817
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Li  Li0  1  0.167  0.700  0.436  1.0
  Li  Li1  1  0.721  0.572  0.146  1.0
  Li  Li2  1  0.296  0.421  0.853  1.0
  Li  Li3  1  0.870  0.293  0.562  1.0
  Ni  Ni4  1  0.003  0.996  0.999  1.0
  O  O5  1  0.336  0.894  0.225  1.0
  O  O6  1  0.865  0.735  0.888  1.0
  O  O7  1  0.502  0.587  0.656  1.0
  O  O8  1  0.093  0.406  0.342  1.0
  O  O9  1  0.603  0.258  0.110  1.0
  O  O10  1  0.233  0.099  0.773  1.0
  O  O11  1  0.684  0.997  0.499  1.0
  Si  Si12  1  0.567  0.847  0.710  1.0
  Si  Si13  1  0.417  0.146  0.288  1.0
[/CIF]
.
The compound described by 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. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li4Si2NiO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.510
_cell_length_b   5.316
_cell_length_c   6.771
_cell_angle_alpha   80.989
_cell_angle_beta   89.964
_cell_angle_gamma   64.908
_symmetry_Int_Tables_number   1
_cell_volume   144.817
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Li  Li0  1  0.167  0.700  0.436  1.0
  Li  Li1  1  0.721  0.572  0.146  1.0
  Li  Li2  1  0.296  0.421  0.853  1.0
  Li  Li3  1  0.870  0.293  0.562  1.0
  Ni  Ni4  1  0.003  0.996  0.999  1.0
  O  O5  1  0.336  0.894  0.225  1.0
  O  O6  1  0.865  0.735  0.888  1.0
  O  O7  1  0.502  0.587  0.656  1.0
  O  O8  1  0.093  0.406  0.342  1.0
  O  O9  1  0.603  0.258  0.110  1.0
  O  O10  1  0.233  0.099  0.773  1.0
  O  O11  1  0.684  0.997  0.499  1.0
  Si  Si12  1  0.567  0.847  0.710  1.0
  Si  Si13  1  0.417  0.146  0.288  1.0
[/CIF]
.