The compound described by K2Sn3O7 crystallizes in the orthorhombic Pnma space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one O(3), one O(5), two equivalent O(2), two equivalent O(4), and two equivalent O(7) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to two equivalent O(3), two equivalent O(6), and three equivalent O(1) atoms. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one O(6), two equivalent O(5), and three equivalent O(7) atoms to form a mixture of corner and edge-sharing SnO6 octahedra. The corner-sharing octahedral tilt angles range from 43-51°. In the second Sn site, Sn(2) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing SnO6 octahedra. The corner-sharing octahedral tilt angles are 51°. In the third Sn site, Sn(3) is bonded to one O(4), one O(6), two equivalent O(1), and two equivalent O(2) atoms to form a mixture of corner and edge-sharing SnO6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are seven inequivalent O sites. In the first O site, O(4) is bonded to two equivalent K(1), one Sn(3), and two equivalent Sn(2) atoms to form distorted OK2Sn3 trigonal bipyramids that share corners with two equivalent O(2)K2Sn3 square pyramids, corners with two equivalent O(1)K3Sn2 square pyramids, edges with three equivalent O(2)K2Sn3 square pyramids, and edges with two equivalent O(4)K2Sn3 trigonal bipyramids. In the second O site, O(5) is bonded in a 4-coordinate geometry to one K(1), one Sn(2), and two equivalent Sn(1) atoms. In the third O site, O(6) is bonded in a 4-coordinate geometry to two equivalent K(2), one Sn(1), and one Sn(3) atom. In the fourth O site, O(7) is bonded in a 5-coordinate geometry to two equivalent K(1) and three equivalent Sn(1) atoms. In the fifth O site, O(1) is bonded to three equivalent K(2) and two equivalent Sn(3) atoms to form distorted OK3Sn2 square pyramids that share corners with two equivalent O(2)K2Sn3 square pyramids, corners with two equivalent O(4)K2Sn3 trigonal bipyramids,  an edgeedge with one O(2)K2Sn3 square pyramid, and edges with four equivalent O(1)K3Sn2 square pyramids. In the sixth O site, O(2) is bonded to two equivalent K(1), one Sn(2), and two equivalent Sn(3) atoms to form distorted OK2Sn3 square pyramids that share corners with two equivalent O(1)K3Sn2 square pyramids, corners with two equivalent O(4)K2Sn3 trigonal bipyramids,  an edgeedge with one O(1)K3Sn2 square pyramid, edges with two equivalent O(2)K2Sn3 square pyramids, and edges with three equivalent O(4)K2Sn3 trigonal bipyramids. In the seventh O site, O(3) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), and two equivalent Sn(2) atoms. is represented by the CIF file [CIF]
data_K2Sn3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.198
_cell_length_b   12.942
_cell_length_c   17.113
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   708.320
_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
  K  K0  1  0.250  0.442  0.306  1.0
  K  K1  1  0.750  0.558  0.694  1.0
  K  K2  1  0.750  0.942  0.194  1.0
  K  K3  1  0.250  0.058  0.806  1.0
  K  K4  1  0.250  0.894  0.434  1.0
  K  K5  1  0.750  0.106  0.566  1.0
  K  K6  1  0.750  0.394  0.066  1.0
  K  K7  1  0.250  0.606  0.934  1.0
  Sn  Sn8  1  0.250  0.112  0.019  1.0
  Sn  Sn9  1  0.750  0.888  0.981  1.0
  Sn  Sn10  1  0.750  0.612  0.481  1.0
  Sn  Sn11  1  0.250  0.388  0.519  1.0
  Sn  Sn12  1  0.250  0.710  0.292  1.0
  Sn  Sn13  1  0.750  0.290  0.708  1.0
  Sn  Sn14  1  0.750  0.210  0.208  1.0
  Sn  Sn15  1  0.250  0.790  0.792  1.0
  Sn  Sn16  1  0.250  0.167  0.376  1.0
  Sn  Sn17  1  0.750  0.833  0.624  1.0
  Sn  Sn18  1  0.750  0.667  0.124  1.0
  Sn  Sn19  1  0.250  0.333  0.876  1.0
  O  O20  1  0.250  0.572  0.095  1.0
  O  O21  1  0.750  0.428  0.905  1.0
  O  O22  1  0.750  0.072  0.405  1.0
  O  O23  1  0.250  0.928  0.595  1.0
  O  O24  1  0.250  0.761  0.174  1.0
  O  O25  1  0.750  0.239  0.826  1.0
  O  O26  1  0.750  0.261  0.326  1.0
  O  O27  1  0.250  0.739  0.674  1.0
  O  O28  1  0.250  0.304  0.178  1.0
  O  O29  1  0.750  0.696  0.822  1.0
  O  O30  1  0.750  0.804  0.322  1.0
  O  O31  1  0.250  0.196  0.678  1.0
  O  O32  1  0.250  0.112  0.251  1.0
  O  O33  1  0.750  0.888  0.749  1.0
  O  O34  1  0.750  0.612  0.249  1.0
  O  O35  1  0.250  0.388  0.751  1.0
  O  O36  1  0.250  0.631  0.400  1.0
  O  O37  1  0.750  0.369  0.600  1.0
  O  O38  1  0.750  0.131  0.100  1.0
  O  O39  1  0.250  0.869  0.900  1.0
  O  O40  1  0.250  0.242  0.481  1.0
  O  O41  1  0.750  0.758  0.519  1.0
  O  O42  1  0.750  0.742  0.019  1.0
  O  O43  1  0.250  0.258  0.981  1.0
  O  O44  1  0.250  0.553  0.551  1.0
  O  O45  1  0.750  0.447  0.449  1.0
  O  O46  1  0.750  0.053  0.949  1.0
  O  O47  1  0.250  0.947  0.051  1.0
[/CIF]
.
The compound described by K2Sn3O7 crystallizes in the orthorhombic Pnma space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one O(3), one O(5), two equivalent O(2), two equivalent O(4), and two equivalent O(7) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to two equivalent O(3), two equivalent O(6), and three equivalent O(1) atoms. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one O(6), two equivalent O(5), and three equivalent O(7) atoms to form a mixture of corner and edge-sharing SnO6 octahedra. The corner-sharing octahedral tilt angles range from 43-51°. In the second Sn site, Sn(2) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing SnO6 octahedra. The corner-sharing octahedral tilt angles are 51°. In the third Sn site, Sn(3) is bonded to one O(4), one O(6), two equivalent O(1), and two equivalent O(2) atoms to form a mixture of corner and edge-sharing SnO6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are seven inequivalent O sites. In the first O site, O(4) is bonded to two equivalent K(1), one Sn(3), and two equivalent Sn(2) atoms to form distorted OK2Sn3 trigonal bipyramids that share corners with two equivalent O(2)K2Sn3 square pyramids, corners with two equivalent O(1)K3Sn2 square pyramids, edges with three equivalent O(2)K2Sn3 square pyramids, and edges with two equivalent O(4)K2Sn3 trigonal bipyramids. In the second O site, O(5) is bonded in a 4-coordinate geometry to one K(1), one Sn(2), and two equivalent Sn(1) atoms. In the third O site, O(6) is bonded in a 4-coordinate geometry to two equivalent K(2), one Sn(1), and one Sn(3) atom. In the fourth O site, O(7) is bonded in a 5-coordinate geometry to two equivalent K(1) and three equivalent Sn(1) atoms. In the fifth O site, O(1) is bonded to three equivalent K(2) and two equivalent Sn(3) atoms to form distorted OK3Sn2 square pyramids that share corners with two equivalent O(2)K2Sn3 square pyramids, corners with two equivalent O(4)K2Sn3 trigonal bipyramids,  an edgeedge with one O(2)K2Sn3 square pyramid, and edges with four equivalent O(1)K3Sn2 square pyramids. In the sixth O site, O(2) is bonded to two equivalent K(1), one Sn(2), and two equivalent Sn(3) atoms to form distorted OK2Sn3 square pyramids that share corners with two equivalent O(1)K3Sn2 square pyramids, corners with two equivalent O(4)K2Sn3 trigonal bipyramids,  an edgeedge with one O(1)K3Sn2 square pyramid, edges with two equivalent O(2)K2Sn3 square pyramids, and edges with three equivalent O(4)K2Sn3 trigonal bipyramids. In the seventh O site, O(3) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), and two equivalent Sn(2) atoms. is represented by the CIF file [CIF]
data_K2Sn3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.198
_cell_length_b   12.942
_cell_length_c   17.113
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   708.320
_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
  K  K0  1  0.250  0.442  0.306  1.0
  K  K1  1  0.750  0.558  0.694  1.0
  K  K2  1  0.750  0.942  0.194  1.0
  K  K3  1  0.250  0.058  0.806  1.0
  K  K4  1  0.250  0.894  0.434  1.0
  K  K5  1  0.750  0.106  0.566  1.0
  K  K6  1  0.750  0.394  0.066  1.0
  K  K7  1  0.250  0.606  0.934  1.0
  Sn  Sn8  1  0.250  0.112  0.019  1.0
  Sn  Sn9  1  0.750  0.888  0.981  1.0
  Sn  Sn10  1  0.750  0.612  0.481  1.0
  Sn  Sn11  1  0.250  0.388  0.519  1.0
  Sn  Sn12  1  0.250  0.710  0.292  1.0
  Sn  Sn13  1  0.750  0.290  0.708  1.0
  Sn  Sn14  1  0.750  0.210  0.208  1.0
  Sn  Sn15  1  0.250  0.790  0.792  1.0
  Sn  Sn16  1  0.250  0.167  0.376  1.0
  Sn  Sn17  1  0.750  0.833  0.624  1.0
  Sn  Sn18  1  0.750  0.667  0.124  1.0
  Sn  Sn19  1  0.250  0.333  0.876  1.0
  O  O20  1  0.250  0.572  0.095  1.0
  O  O21  1  0.750  0.428  0.905  1.0
  O  O22  1  0.750  0.072  0.405  1.0
  O  O23  1  0.250  0.928  0.595  1.0
  O  O24  1  0.250  0.761  0.174  1.0
  O  O25  1  0.750  0.239  0.826  1.0
  O  O26  1  0.750  0.261  0.326  1.0
  O  O27  1  0.250  0.739  0.674  1.0
  O  O28  1  0.250  0.304  0.178  1.0
  O  O29  1  0.750  0.696  0.822  1.0
  O  O30  1  0.750  0.804  0.322  1.0
  O  O31  1  0.250  0.196  0.678  1.0
  O  O32  1  0.250  0.112  0.251  1.0
  O  O33  1  0.750  0.888  0.749  1.0
  O  O34  1  0.750  0.612  0.249  1.0
  O  O35  1  0.250  0.388  0.751  1.0
  O  O36  1  0.250  0.631  0.400  1.0
  O  O37  1  0.750  0.369  0.600  1.0
  O  O38  1  0.750  0.131  0.100  1.0
  O  O39  1  0.250  0.869  0.900  1.0
  O  O40  1  0.250  0.242  0.481  1.0
  O  O41  1  0.750  0.758  0.519  1.0
  O  O42  1  0.750  0.742  0.019  1.0
  O  O43  1  0.250  0.258  0.981  1.0
  O  O44  1  0.250  0.553  0.551  1.0
  O  O45  1  0.750  0.447  0.449  1.0
  O  O46  1  0.750  0.053  0.949  1.0
  O  O47  1  0.250  0.947  0.051  1.0
[/CIF]
.