The material described by Ca2V2O9 crystallizes in the triclinic P-1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(8), and two equivalent O(7) atoms. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one O(2), one O(5), one O(6), one O(7), one O(9), and two equivalent O(4) atoms. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing VO4 tetrahedra. In the second V site, V(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form corner-sharing VO4 tetrahedra. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one V(1) and one V(2) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Ca(2), and one V(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Ca(1) and one V(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one V(1) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ca(1), one Ca(2), and one V(2) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Ca(1), one Ca(2), and one V(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Ca(2), two equivalent Ca(1), and one V(2) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Ca(1) and one O(9) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one Ca(2) and one O(8) atom. is represented by the CIF file [CIF]
data_Ca2V2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.645
_cell_length_b   8.495
_cell_length_c   8.509
_cell_angle_alpha   109.638
_cell_angle_beta   92.924
_cell_angle_gamma   112.772
_symmetry_Int_Tables_number   1
_cell_volume   407.999
_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  0.135  0.953  0.297  1.0
  Ca  Ca1  1  0.865  0.047  0.703  1.0
  Ca  Ca2  1  0.327  0.940  0.791  1.0
  Ca  Ca3  1  0.673  0.060  0.209  1.0
  V  V4  1  0.741  0.733  0.861  1.0
  V  V5  1  0.259  0.267  0.139  1.0
  V  V6  1  0.486  0.256  0.644  1.0
  V  V7  1  0.514  0.744  0.356  1.0
  O  O8  1  0.540  0.496  0.738  1.0
  O  O9  1  0.460  0.504  0.262  1.0
  O  O10  1  0.939  0.816  0.748  1.0
  O  O11  1  0.061  0.184  0.252  1.0
  O  O12  1  0.876  0.749  0.042  1.0
  O  O13  1  0.124  0.251  0.958  1.0
  O  O14  1  0.619  0.888  0.915  1.0
  O  O15  1  0.381  0.112  0.085  1.0
  O  O16  1  0.633  0.198  0.769  1.0
  O  O17  1  0.367  0.802  0.231  1.0
  O  O18  1  0.537  0.197  0.443  1.0
  O  O19  1  0.463  0.803  0.557  1.0
  O  O20  1  0.212  0.096  0.614  1.0
  O  O21  1  0.788  0.904  0.386  1.0
  O  O22  1  0.019  0.401  0.636  1.0
  O  O23  1  0.981  0.599  0.364  1.0
  O  O24  1  0.904  0.452  0.238  1.0
  O  O25  1  0.096  0.548  0.762  1.0
[/CIF]
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The material described by Ca2V2O9 crystallizes in the triclinic P-1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(8), and two equivalent O(7) atoms. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one O(2), one O(5), one O(6), one O(7), one O(9), and two equivalent O(4) atoms. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing VO4 tetrahedra. In the second V site, V(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form corner-sharing VO4 tetrahedra. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one V(1) and one V(2) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Ca(2), and one V(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Ca(1) and one V(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one V(1) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ca(1), one Ca(2), and one V(2) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Ca(1), one Ca(2), and one V(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Ca(2), two equivalent Ca(1), and one V(2) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Ca(1) and one O(9) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one Ca(2) and one O(8) atom. is represented by the CIF file [CIF]
data_Ca2V2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.645
_cell_length_b   8.495
_cell_length_c   8.509
_cell_angle_alpha   109.638
_cell_angle_beta   92.924
_cell_angle_gamma   112.772
_symmetry_Int_Tables_number   1
_cell_volume   407.999
_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  0.135  0.953  0.297  1.0
  Ca  Ca1  1  0.865  0.047  0.703  1.0
  Ca  Ca2  1  0.327  0.940  0.791  1.0
  Ca  Ca3  1  0.673  0.060  0.209  1.0
  V  V4  1  0.741  0.733  0.861  1.0
  V  V5  1  0.259  0.267  0.139  1.0
  V  V6  1  0.486  0.256  0.644  1.0
  V  V7  1  0.514  0.744  0.356  1.0
  O  O8  1  0.540  0.496  0.738  1.0
  O  O9  1  0.460  0.504  0.262  1.0
  O  O10  1  0.939  0.816  0.748  1.0
  O  O11  1  0.061  0.184  0.252  1.0
  O  O12  1  0.876  0.749  0.042  1.0
  O  O13  1  0.124  0.251  0.958  1.0
  O  O14  1  0.619  0.888  0.915  1.0
  O  O15  1  0.381  0.112  0.085  1.0
  O  O16  1  0.633  0.198  0.769  1.0
  O  O17  1  0.367  0.802  0.231  1.0
  O  O18  1  0.537  0.197  0.443  1.0
  O  O19  1  0.463  0.803  0.557  1.0
  O  O20  1  0.212  0.096  0.614  1.0
  O  O21  1  0.788  0.904  0.386  1.0
  O  O22  1  0.019  0.401  0.636  1.0
  O  O23  1  0.981  0.599  0.364  1.0
  O  O24  1  0.904  0.452  0.238  1.0
  O  O25  1  0.096  0.548  0.762  1.0
[/CIF]
.