The crystal structure described by Li2NiSi2O6 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, and corners with two equivalent Ni(1)O4 trigonal pyramids. In the second Li site, Li(2) is bonded to one O(4), one O(5), and two equivalent O(6) atoms to form distorted LiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Si(2)O4 tetrahedra, and  a cornercorner with one Ni(1)O4 trigonal pyramid. Ni(1) is bonded to one O(2), one O(5), and two equivalent O(1) atoms to form distorted NiO4 trigonal pyramids that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra, and corners with two equivalent Ni(1)O4 trigonal pyramids. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with three equivalent Ni(1)O4 trigonal pyramids. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, and  a cornercorner with one Ni(1)O4 trigonal pyramid. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Ni(1) and one Si(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Li(1), one Ni(1), and one Si(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(4) is bonded to one Li(1), one Li(2), one Si(1), and one Si(2) atom to form distorted OLi2Si2 tetrahedra that share corners with three equivalent O(5)Li2SiNi tetrahedra and corners with four equivalent O(6)Li3Si tetrahedra. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one Ni(1), and one Si(2) atom to form distorted OLi2SiNi tetrahedra that share corners with three equivalent O(4)Li2Si2 tetrahedra and corners with four equivalent O(6)Li3Si tetrahedra. In the sixth O site, O(6) is bonded to one Li(1), two equivalent Li(2), and one Si(2) atom to form distorted OLi3Si tetrahedra that share corners with two equivalent O(6)Li3Si tetrahedra, corners with four equivalent O(4)Li2Si2 tetrahedra, and corners with four equivalent O(5)Li2SiNi tetrahedra. is represented by the CIF file [CIF]
data_Li2Si2NiO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.589
_cell_length_b   5.295
_cell_length_c   9.529
_cell_angle_alpha   86.205
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   231.040
_cell_formula_units_Z   2
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  0.201  0.671  0.675  1.0
  Li  Li1  1  0.713  0.838  0.517  1.0
  Li  Li2  1  0.213  0.162  0.483  1.0
  Li  Li3  1  0.701  0.329  0.325  1.0
  Si  Si4  1  0.217  0.137  0.824  1.0
  Si  Si5  1  0.713  0.308  0.656  1.0
  Si  Si6  1  0.213  0.692  0.344  1.0
  Si  Si7  1  0.717  0.863  0.176  1.0
  Ni  Ni8  1  0.630  0.623  0.885  1.0
  Ni  Ni9  1  0.130  0.377  0.115  1.0
  O  O10  1  0.317  0.335  0.937  1.0
  O  O11  1  0.309  0.847  0.839  1.0
  O  O12  1  0.865  0.148  0.792  1.0
  O  O13  1  0.355  0.271  0.673  1.0
  O  O14  1  0.775  0.603  0.682  1.0
  O  O15  1  0.800  0.199  0.510  1.0
  O  O16  1  0.300  0.801  0.490  1.0
  O  O17  1  0.275  0.397  0.318  1.0
  O  O18  1  0.855  0.729  0.327  1.0
  O  O19  1  0.365  0.852  0.208  1.0
  O  O20  1  0.809  0.153  0.161  1.0
  O  O21  1  0.817  0.665  0.063  1.0
[/CIF]
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The crystal structure described by Li2NiSi2O6 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, and corners with two equivalent Ni(1)O4 trigonal pyramids. In the second Li site, Li(2) is bonded to one O(4), one O(5), and two equivalent O(6) atoms to form distorted LiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Si(2)O4 tetrahedra, and  a cornercorner with one Ni(1)O4 trigonal pyramid. Ni(1) is bonded to one O(2), one O(5), and two equivalent O(1) atoms to form distorted NiO4 trigonal pyramids that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra, and corners with two equivalent Ni(1)O4 trigonal pyramids. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with three equivalent Ni(1)O4 trigonal pyramids. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, and  a cornercorner with one Ni(1)O4 trigonal pyramid. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Ni(1) and one Si(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Li(1), one Ni(1), and one Si(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(4) is bonded to one Li(1), one Li(2), one Si(1), and one Si(2) atom to form distorted OLi2Si2 tetrahedra that share corners with three equivalent O(5)Li2SiNi tetrahedra and corners with four equivalent O(6)Li3Si tetrahedra. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one Ni(1), and one Si(2) atom to form distorted OLi2SiNi tetrahedra that share corners with three equivalent O(4)Li2Si2 tetrahedra and corners with four equivalent O(6)Li3Si tetrahedra. In the sixth O site, O(6) is bonded to one Li(1), two equivalent Li(2), and one Si(2) atom to form distorted OLi3Si tetrahedra that share corners with two equivalent O(6)Li3Si tetrahedra, corners with four equivalent O(4)Li2Si2 tetrahedra, and corners with four equivalent O(5)Li2SiNi tetrahedra. is represented by the CIF file [CIF]
data_Li2Si2NiO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.589
_cell_length_b   5.295
_cell_length_c   9.529
_cell_angle_alpha   86.205
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   231.040
_cell_formula_units_Z   2
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  0.201  0.671  0.675  1.0
  Li  Li1  1  0.713  0.838  0.517  1.0
  Li  Li2  1  0.213  0.162  0.483  1.0
  Li  Li3  1  0.701  0.329  0.325  1.0
  Si  Si4  1  0.217  0.137  0.824  1.0
  Si  Si5  1  0.713  0.308  0.656  1.0
  Si  Si6  1  0.213  0.692  0.344  1.0
  Si  Si7  1  0.717  0.863  0.176  1.0
  Ni  Ni8  1  0.630  0.623  0.885  1.0
  Ni  Ni9  1  0.130  0.377  0.115  1.0
  O  O10  1  0.317  0.335  0.937  1.0
  O  O11  1  0.309  0.847  0.839  1.0
  O  O12  1  0.865  0.148  0.792  1.0
  O  O13  1  0.355  0.271  0.673  1.0
  O  O14  1  0.775  0.603  0.682  1.0
  O  O15  1  0.800  0.199  0.510  1.0
  O  O16  1  0.300  0.801  0.490  1.0
  O  O17  1  0.275  0.397  0.318  1.0
  O  O18  1  0.855  0.729  0.327  1.0
  O  O19  1  0.365  0.852  0.208  1.0
  O  O20  1  0.809  0.153  0.161  1.0
  O  O21  1  0.817  0.665  0.063  1.0
[/CIF]
.