The crystal structure described by CaV(Si2O7)2 crystallizes in the orthorhombic Cmc2_1 space group. Ca(1) is bonded in a 7-coordinate geometry to one O(8), two equivalent O(1), two equivalent O(2), and two equivalent O(7) atoms. V(1) is bonded to one O(6), two equivalent O(1), and two equivalent O(2) atoms to form distorted VO5 trigonal bipyramids that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)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(4), and one O(5) atom to form SiO4 tetrahedra that share corners with three equivalent Si(2)O4 tetrahedra and  a cornercorner with one V(1)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with three equivalent Si(1)O4 tetrahedra and  a cornercorner with one V(1)O5 trigonal bipyramid. There are eight inequivalent O sites. In the first O site, O(3) is bonded in a linear geometry to one Si(1) and one Si(2) atom. In the second O site, O(4) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the third O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(6) is bonded in a single-bond geometry to one V(1) atom. In the fifth O site, O(7) is bonded in a distorted L-shaped geometry to one Ca(1) and one O(7) atom. In the sixth O site, O(8) is bonded in a single-bond geometry to one Ca(1) atom. In the seventh O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one V(1), and one Si(1) atom. In the eighth O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one V(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaV(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.608
_cell_length_b   8.608
_cell_length_c   9.058
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   104.012
_symmetry_Int_Tables_number   1
_cell_volume   651.099
_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
  Ca  Ca0  1  0.222  0.222  0.794  1.0
  Ca  Ca1  1  0.778  0.778  0.294  1.0
  V  V2  1  0.952  0.952  0.615  1.0
  V  V3  1  0.048  0.048  0.115  1.0
  Si  Si4  1  0.316  0.885  0.649  1.0
  Si  Si5  1  0.885  0.316  0.649  1.0
  Si  Si6  1  0.684  0.115  0.149  1.0
  Si  Si7  1  0.115  0.684  0.149  1.0
  Si  Si8  1  0.361  0.927  0.989  1.0
  Si  Si9  1  0.927  0.361  0.989  1.0
  Si  Si10  1  0.639  0.073  0.489  1.0
  Si  Si11  1  0.073  0.639  0.489  1.0
  O  O12  1  0.178  0.988  0.645  1.0
  O  O13  1  0.988  0.178  0.645  1.0
  O  O14  1  0.822  0.012  0.145  1.0
  O  O15  1  0.012  0.822  0.145  1.0
  O  O16  1  0.230  0.039  0.996  1.0
  O  O17  1  0.039  0.230  0.996  1.0
  O  O18  1  0.770  0.961  0.496  1.0
  O  O19  1  0.961  0.770  0.496  1.0
  O  O20  1  0.466  0.970  0.546  1.0
  O  O21  1  0.970  0.466  0.546  1.0
  O  O22  1  0.534  0.030  0.046  1.0
  O  O23  1  0.030  0.534  0.046  1.0
  O  O24  1  0.234  0.705  0.588  1.0
  O  O25  1  0.705  0.234  0.588  1.0
  O  O26  1  0.766  0.295  0.088  1.0
  O  O27  1  0.295  0.766  0.088  1.0
  O  O28  1  0.380  0.880  0.817  1.0
  O  O29  1  0.880  0.380  0.817  1.0
  O  O30  1  0.620  0.120  0.317  1.0
  O  O31  1  0.120  0.620  0.317  1.0
  O  O32  1  0.882  0.882  0.773  1.0
  O  O33  1  0.118  0.118  0.273  1.0
  O  O34  1  0.487  0.393  0.837  1.0
  O  O35  1  0.393  0.487  0.837  1.0
  O  O36  1  0.513  0.607  0.337  1.0
  O  O37  1  0.607  0.513  0.337  1.0
  O  O38  1  0.345  0.345  0.593  1.0
  O  O39  1  0.655  0.655  0.093  1.0
[/CIF]
.
The crystal structure described by CaV(Si2O7)2 crystallizes in the orthorhombic Cmc2_1 space group. Ca(1) is bonded in a 7-coordinate geometry to one O(8), two equivalent O(1), two equivalent O(2), and two equivalent O(7) atoms. V(1) is bonded to one O(6), two equivalent O(1), and two equivalent O(2) atoms to form distorted VO5 trigonal bipyramids that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)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(4), and one O(5) atom to form SiO4 tetrahedra that share corners with three equivalent Si(2)O4 tetrahedra and  a cornercorner with one V(1)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with three equivalent Si(1)O4 tetrahedra and  a cornercorner with one V(1)O5 trigonal bipyramid. There are eight inequivalent O sites. In the first O site, O(3) is bonded in a linear geometry to one Si(1) and one Si(2) atom. In the second O site, O(4) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the third O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(6) is bonded in a single-bond geometry to one V(1) atom. In the fifth O site, O(7) is bonded in a distorted L-shaped geometry to one Ca(1) and one O(7) atom. In the sixth O site, O(8) is bonded in a single-bond geometry to one Ca(1) atom. In the seventh O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one V(1), and one Si(1) atom. In the eighth O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one V(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaV(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.608
_cell_length_b   8.608
_cell_length_c   9.058
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   104.012
_symmetry_Int_Tables_number   1
_cell_volume   651.099
_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
  Ca  Ca0  1  0.222  0.222  0.794  1.0
  Ca  Ca1  1  0.778  0.778  0.294  1.0
  V  V2  1  0.952  0.952  0.615  1.0
  V  V3  1  0.048  0.048  0.115  1.0
  Si  Si4  1  0.316  0.885  0.649  1.0
  Si  Si5  1  0.885  0.316  0.649  1.0
  Si  Si6  1  0.684  0.115  0.149  1.0
  Si  Si7  1  0.115  0.684  0.149  1.0
  Si  Si8  1  0.361  0.927  0.989  1.0
  Si  Si9  1  0.927  0.361  0.989  1.0
  Si  Si10  1  0.639  0.073  0.489  1.0
  Si  Si11  1  0.073  0.639  0.489  1.0
  O  O12  1  0.178  0.988  0.645  1.0
  O  O13  1  0.988  0.178  0.645  1.0
  O  O14  1  0.822  0.012  0.145  1.0
  O  O15  1  0.012  0.822  0.145  1.0
  O  O16  1  0.230  0.039  0.996  1.0
  O  O17  1  0.039  0.230  0.996  1.0
  O  O18  1  0.770  0.961  0.496  1.0
  O  O19  1  0.961  0.770  0.496  1.0
  O  O20  1  0.466  0.970  0.546  1.0
  O  O21  1  0.970  0.466  0.546  1.0
  O  O22  1  0.534  0.030  0.046  1.0
  O  O23  1  0.030  0.534  0.046  1.0
  O  O24  1  0.234  0.705  0.588  1.0
  O  O25  1  0.705  0.234  0.588  1.0
  O  O26  1  0.766  0.295  0.088  1.0
  O  O27  1  0.295  0.766  0.088  1.0
  O  O28  1  0.380  0.880  0.817  1.0
  O  O29  1  0.880  0.380  0.817  1.0
  O  O30  1  0.620  0.120  0.317  1.0
  O  O31  1  0.120  0.620  0.317  1.0
  O  O32  1  0.882  0.882  0.773  1.0
  O  O33  1  0.118  0.118  0.273  1.0
  O  O34  1  0.487  0.393  0.837  1.0
  O  O35  1  0.393  0.487  0.837  1.0
  O  O36  1  0.513  0.607  0.337  1.0
  O  O37  1  0.607  0.513  0.337  1.0
  O  O38  1  0.345  0.345  0.593  1.0
  O  O39  1  0.655  0.655  0.093  1.0
[/CIF]
.