The compound described by Li2SnP2O7 crystallizes in the monoclinic C2/c space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one O(5), one O(6), one O(7), and two equivalent O(2) atoms. In the second Li site, Li(2) is bonded to two equivalent O(3) and two equivalent O(7) atoms to form LiO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. In the third Li site, Li(3) is bonded to two equivalent O(4) and two equivalent O(6) atoms to form distorted LiO4 trigonal pyramids that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. Sn(1) is bonded in a 3-coordinate geometry to one O(2), one O(3), and one O(5) atom. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one Li(3)O4 trigonal pyramid. In the second P site, P(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one Li(3)O4 trigonal pyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Li(1), one Sn(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Li(2), one Sn(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Li(3) and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Li(1), one Sn(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Li(1), one Li(2), and one P(1) atom. is represented by the CIF file [CIF]
data_Li2SnP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.330
_cell_length_b   7.330
_cell_length_c   13.173
_cell_angle_alpha   89.650
_cell_angle_beta   89.650
_cell_angle_gamma   120.033
_symmetry_Int_Tables_number   1
_cell_volume   612.669
_cell_formula_units_Z   4
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  0.747  0.285  0.495  1.0
  Li  Li1  1  0.285  0.747  0.995  1.0
  Li  Li2  1  0.739  0.261  0.250  1.0
  Li  Li3  1  0.281  0.719  0.250  1.0
  Li  Li4  1  0.719  0.281  0.750  1.0
  Li  Li5  1  0.261  0.739  0.750  1.0
  Li  Li6  1  0.715  0.253  0.005  1.0
  Li  Li7  1  0.253  0.715  0.505  1.0
  Sn  Sn8  1  0.667  0.657  0.379  1.0
  Sn  Sn9  1  0.657  0.667  0.879  1.0
  Sn  Sn10  1  0.343  0.333  0.121  1.0
  Sn  Sn11  1  0.333  0.343  0.621  1.0
  P  P12  1  0.707  0.918  0.115  1.0
  P  P13  1  0.918  0.707  0.615  1.0
  P  P14  1  0.896  0.654  0.144  1.0
  P  P15  1  0.654  0.896  0.644  1.0
  P  P16  1  0.346  0.104  0.356  1.0
  P  P17  1  0.104  0.346  0.856  1.0
  P  P18  1  0.082  0.293  0.385  1.0
  P  P19  1  0.293  0.082  0.885  1.0
  O  O20  1  0.912  0.882  0.122  1.0
  O  O21  1  0.882  0.912  0.622  1.0
  O  O22  1  0.614  0.856  0.006  1.0
  O  O23  1  0.856  0.614  0.506  1.0
  O  O24  1  0.842  0.590  0.258  1.0
  O  O25  1  0.590  0.842  0.758  1.0
  O  O26  1  0.552  0.772  0.195  1.0
  O  O27  1  0.772  0.552  0.695  1.0
  O  O28  1  0.709  0.494  0.079  1.0
  O  O29  1  0.316  0.890  0.382  1.0
  O  O30  1  0.494  0.709  0.579  1.0
  O  O31  1  0.890  0.316  0.882  1.0
  O  O32  1  0.847  0.201  0.371  1.0
  O  O33  1  0.201  0.847  0.871  1.0
  O  O34  1  0.799  0.153  0.129  1.0
  O  O35  1  0.153  0.799  0.629  1.0
  O  O36  1  0.110  0.684  0.118  1.0
  O  O37  1  0.506  0.291  0.421  1.0
  O  O38  1  0.684  0.110  0.618  1.0
  O  O39  1  0.291  0.506  0.921  1.0
  O  O40  1  0.228  0.448  0.305  1.0
  O  O41  1  0.448  0.228  0.805  1.0
  O  O42  1  0.410  0.158  0.242  1.0
  O  O43  1  0.158  0.410  0.742  1.0
  O  O44  1  0.144  0.386  0.494  1.0
  O  O45  1  0.386  0.144  0.994  1.0
  O  O46  1  0.118  0.088  0.378  1.0
  O  O47  1  0.088  0.118  0.878  1.0
[/CIF]
.
The compound described by Li2SnP2O7 crystallizes in the monoclinic C2/c space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one O(5), one O(6), one O(7), and two equivalent O(2) atoms. In the second Li site, Li(2) is bonded to two equivalent O(3) and two equivalent O(7) atoms to form LiO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. In the third Li site, Li(3) is bonded to two equivalent O(4) and two equivalent O(6) atoms to form distorted LiO4 trigonal pyramids that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. Sn(1) is bonded in a 3-coordinate geometry to one O(2), one O(3), and one O(5) atom. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one Li(3)O4 trigonal pyramid. In the second P site, P(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one Li(3)O4 trigonal pyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Li(1), one Sn(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Li(2), one Sn(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Li(3) and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Li(1), one Sn(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Li(1), one Li(2), and one P(1) atom. is represented by the CIF file [CIF]
data_Li2SnP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.330
_cell_length_b   7.330
_cell_length_c   13.173
_cell_angle_alpha   89.650
_cell_angle_beta   89.650
_cell_angle_gamma   120.033
_symmetry_Int_Tables_number   1
_cell_volume   612.669
_cell_formula_units_Z   4
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  0.747  0.285  0.495  1.0
  Li  Li1  1  0.285  0.747  0.995  1.0
  Li  Li2  1  0.739  0.261  0.250  1.0
  Li  Li3  1  0.281  0.719  0.250  1.0
  Li  Li4  1  0.719  0.281  0.750  1.0
  Li  Li5  1  0.261  0.739  0.750  1.0
  Li  Li6  1  0.715  0.253  0.005  1.0
  Li  Li7  1  0.253  0.715  0.505  1.0
  Sn  Sn8  1  0.667  0.657  0.379  1.0
  Sn  Sn9  1  0.657  0.667  0.879  1.0
  Sn  Sn10  1  0.343  0.333  0.121  1.0
  Sn  Sn11  1  0.333  0.343  0.621  1.0
  P  P12  1  0.707  0.918  0.115  1.0
  P  P13  1  0.918  0.707  0.615  1.0
  P  P14  1  0.896  0.654  0.144  1.0
  P  P15  1  0.654  0.896  0.644  1.0
  P  P16  1  0.346  0.104  0.356  1.0
  P  P17  1  0.104  0.346  0.856  1.0
  P  P18  1  0.082  0.293  0.385  1.0
  P  P19  1  0.293  0.082  0.885  1.0
  O  O20  1  0.912  0.882  0.122  1.0
  O  O21  1  0.882  0.912  0.622  1.0
  O  O22  1  0.614  0.856  0.006  1.0
  O  O23  1  0.856  0.614  0.506  1.0
  O  O24  1  0.842  0.590  0.258  1.0
  O  O25  1  0.590  0.842  0.758  1.0
  O  O26  1  0.552  0.772  0.195  1.0
  O  O27  1  0.772  0.552  0.695  1.0
  O  O28  1  0.709  0.494  0.079  1.0
  O  O29  1  0.316  0.890  0.382  1.0
  O  O30  1  0.494  0.709  0.579  1.0
  O  O31  1  0.890  0.316  0.882  1.0
  O  O32  1  0.847  0.201  0.371  1.0
  O  O33  1  0.201  0.847  0.871  1.0
  O  O34  1  0.799  0.153  0.129  1.0
  O  O35  1  0.153  0.799  0.629  1.0
  O  O36  1  0.110  0.684  0.118  1.0
  O  O37  1  0.506  0.291  0.421  1.0
  O  O38  1  0.684  0.110  0.618  1.0
  O  O39  1  0.291  0.506  0.921  1.0
  O  O40  1  0.228  0.448  0.305  1.0
  O  O41  1  0.448  0.228  0.805  1.0
  O  O42  1  0.410  0.158  0.242  1.0
  O  O43  1  0.158  0.410  0.742  1.0
  O  O44  1  0.144  0.386  0.494  1.0
  O  O45  1  0.386  0.144  0.994  1.0
  O  O46  1  0.118  0.088  0.378  1.0
  O  O47  1  0.088  0.118  0.878  1.0
[/CIF]
.