The material described by Zn3Si4(SnO7)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(2), and two equivalent O(7) atoms. In the second Zn site, Zn(2) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted ZnO4 tetrahedra that share corners with four equivalent Si(2)O4 tetrahedra and  an edgeedge with one Sn(1)O6 octahedra. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form SnO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Zn(2)O4 tetrahedra. In the second Sn site, Sn(2) is bonded in a distorted square co-planar geometry to two equivalent O(2) and two equivalent O(4) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Sn(1)O6 octahedra and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Sn(1)O6 octahedra, corners with two equivalent Zn(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Zn(1), one Zn(2), and one Si(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Zn(1), one Sn(1), and one Sn(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Zn(2), one Sn(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sn(1), one Sn(2), and one Si(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Zn(1) and one Si(1) atom. is represented by the CIF card [CIF]
data_Zn3Si4(SnO7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.340
_cell_length_b   9.340
_cell_length_c   10.246
_cell_angle_alpha   60.367
_cell_angle_beta   60.367
_cell_angle_gamma   55.141
_symmetry_Int_Tables_number   1
_cell_volume   608.687
_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
  Zn  Zn0  1  0.049  0.295  0.092  1.0
  Zn  Zn1  1  0.705  0.951  0.408  1.0
  Zn  Zn2  1  0.295  0.049  0.592  1.0
  Zn  Zn3  1  0.406  0.594  0.750  1.0
  Zn  Zn4  1  0.951  0.705  0.908  1.0
  Zn  Zn5  1  0.594  0.406  0.250  1.0
  Si  Si6  1  0.508  0.118  0.704  1.0
  Si  Si7  1  0.118  0.508  0.204  1.0
  Si  Si8  1  0.512  0.239  0.108  1.0
  Si  Si9  1  0.239  0.512  0.608  1.0
  Si  Si10  1  0.882  0.492  0.796  1.0
  Si  Si11  1  0.488  0.761  0.892  1.0
  Si  Si12  1  0.761  0.488  0.392  1.0
  Si  Si13  1  0.492  0.882  0.296  1.0
  Sn  Sn14  1  0.786  0.214  0.750  1.0
  Sn  Sn15  1  0.214  0.786  0.250  1.0
  Sn  Sn16  1  0.000  0.000  0.000  1.0
  Sn  Sn17  1  0.000  0.000  0.500  1.0
  O  O18  1  0.796  0.339  0.322  1.0
  O  O19  1  0.949  0.870  0.400  1.0
  O  O20  1  0.465  0.654  0.083  1.0
  O  O21  1  0.870  0.949  0.900  1.0
  O  O22  1  0.300  0.888  0.328  1.0
  O  O23  1  0.044  0.527  0.635  1.0
  O  O24  1  0.654  0.465  0.583  1.0
  O  O25  1  0.112  0.700  0.172  1.0
  O  O26  1  0.956  0.473  0.365  1.0
  O  O27  1  0.660  0.685  0.272  1.0
  O  O28  1  0.051  0.130  0.600  1.0
  O  O29  1  0.700  0.112  0.672  1.0
  O  O30  1  0.473  0.956  0.865  1.0
  O  O31  1  0.339  0.796  0.822  1.0
  O  O32  1  0.685  0.660  0.772  1.0
  O  O33  1  0.888  0.300  0.828  1.0
  O  O34  1  0.905  0.500  0.941  1.0
  O  O35  1  0.340  0.315  0.728  1.0
  O  O36  1  0.500  0.095  0.559  1.0
  O  O37  1  0.315  0.340  0.228  1.0
  O  O38  1  0.527  0.044  0.135  1.0
  O  O39  1  0.130  0.051  0.100  1.0
  O  O40  1  0.500  0.905  0.441  1.0
  O  O41  1  0.535  0.346  0.917  1.0
  O  O42  1  0.095  0.500  0.059  1.0
  O  O43  1  0.346  0.535  0.417  1.0
  O  O44  1  0.661  0.204  0.178  1.0
  O  O45  1  0.204  0.661  0.678  1.0
[/CIF]
.
The material described by Zn3Si4(SnO7)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(2), and two equivalent O(7) atoms. In the second Zn site, Zn(2) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted ZnO4 tetrahedra that share corners with four equivalent Si(2)O4 tetrahedra and  an edgeedge with one Sn(1)O6 octahedra. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form SnO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Zn(2)O4 tetrahedra. In the second Sn site, Sn(2) is bonded in a distorted square co-planar geometry to two equivalent O(2) and two equivalent O(4) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Sn(1)O6 octahedra and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Sn(1)O6 octahedra, corners with two equivalent Zn(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Zn(1), one Zn(2), and one Si(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Zn(1), one Sn(1), and one Sn(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Zn(2), one Sn(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sn(1), one Sn(2), and one Si(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Zn(1) and one Si(1) atom. is represented by the CIF card [CIF]
data_Zn3Si4(SnO7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.340
_cell_length_b   9.340
_cell_length_c   10.246
_cell_angle_alpha   60.367
_cell_angle_beta   60.367
_cell_angle_gamma   55.141
_symmetry_Int_Tables_number   1
_cell_volume   608.687
_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
  Zn  Zn0  1  0.049  0.295  0.092  1.0
  Zn  Zn1  1  0.705  0.951  0.408  1.0
  Zn  Zn2  1  0.295  0.049  0.592  1.0
  Zn  Zn3  1  0.406  0.594  0.750  1.0
  Zn  Zn4  1  0.951  0.705  0.908  1.0
  Zn  Zn5  1  0.594  0.406  0.250  1.0
  Si  Si6  1  0.508  0.118  0.704  1.0
  Si  Si7  1  0.118  0.508  0.204  1.0
  Si  Si8  1  0.512  0.239  0.108  1.0
  Si  Si9  1  0.239  0.512  0.608  1.0
  Si  Si10  1  0.882  0.492  0.796  1.0
  Si  Si11  1  0.488  0.761  0.892  1.0
  Si  Si12  1  0.761  0.488  0.392  1.0
  Si  Si13  1  0.492  0.882  0.296  1.0
  Sn  Sn14  1  0.786  0.214  0.750  1.0
  Sn  Sn15  1  0.214  0.786  0.250  1.0
  Sn  Sn16  1  0.000  0.000  0.000  1.0
  Sn  Sn17  1  0.000  0.000  0.500  1.0
  O  O18  1  0.796  0.339  0.322  1.0
  O  O19  1  0.949  0.870  0.400  1.0
  O  O20  1  0.465  0.654  0.083  1.0
  O  O21  1  0.870  0.949  0.900  1.0
  O  O22  1  0.300  0.888  0.328  1.0
  O  O23  1  0.044  0.527  0.635  1.0
  O  O24  1  0.654  0.465  0.583  1.0
  O  O25  1  0.112  0.700  0.172  1.0
  O  O26  1  0.956  0.473  0.365  1.0
  O  O27  1  0.660  0.685  0.272  1.0
  O  O28  1  0.051  0.130  0.600  1.0
  O  O29  1  0.700  0.112  0.672  1.0
  O  O30  1  0.473  0.956  0.865  1.0
  O  O31  1  0.339  0.796  0.822  1.0
  O  O32  1  0.685  0.660  0.772  1.0
  O  O33  1  0.888  0.300  0.828  1.0
  O  O34  1  0.905  0.500  0.941  1.0
  O  O35  1  0.340  0.315  0.728  1.0
  O  O36  1  0.500  0.095  0.559  1.0
  O  O37  1  0.315  0.340  0.228  1.0
  O  O38  1  0.527  0.044  0.135  1.0
  O  O39  1  0.130  0.051  0.100  1.0
  O  O40  1  0.500  0.905  0.441  1.0
  O  O41  1  0.535  0.346  0.917  1.0
  O  O42  1  0.095  0.500  0.059  1.0
  O  O43  1  0.346  0.535  0.417  1.0
  O  O44  1  0.661  0.204  0.178  1.0
  O  O45  1  0.204  0.661  0.678  1.0
[/CIF]
.