The compound described by K4V2O9 crystallizes in the orthorhombic Cmcm space group. There are three inequivalent K sites. In the first K site, K(1) is bonded to one O(3), two equivalent O(4), and four equivalent O(2) atoms to form KO7 pentagonal bipyramids that share corners with two equivalent V(1)O4 tetrahedra, edges with two equivalent K(1)O7 pentagonal bipyramids, and edges with two equivalent V(1)O4 tetrahedra. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(4), and four equivalent O(1) atoms. In the third K site, K(3) is bonded in a 9-coordinate geometry to one O(3), two equivalent O(2), two equivalent O(4), and four equivalent O(1) atoms. V(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form VO4 tetrahedra that share  a cornercorner with one K(1)O7 pentagonal bipyramid,  a cornercorner with one V(1)O4 tetrahedra, and  an edgeedge with one K(1)O7 pentagonal bipyramid. There are four inequivalent O sites. In the first O site, O(2) is bonded in a distorted single-bond geometry to two equivalent K(1), two equivalent K(3), and one V(1) atom. In the second O site, O(3) is bonded in a distorted linear geometry to one K(1), one K(2), two equivalent K(3), and two equivalent V(1) atoms. In the third O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one K(2), and two equivalent K(3) atoms. In the fourth O site, O(1) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(3), and one V(1) atom. is represented by the CIF card [CIF]
data_K4V2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.401
_cell_length_b   8.401
_cell_length_c   8.109
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   96.437
_symmetry_Int_Tables_number   1
_cell_volume   568.713
_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
  K  K0  1  0.465  0.535  0.250  1.0
  K  K1  1  0.535  0.465  0.750  1.0
  K  K2  1  0.986  0.014  0.250  1.0
  K  K3  1  0.014  0.986  0.750  1.0
  K  K4  1  0.918  0.530  0.250  1.0
  K  K5  1  0.530  0.918  0.750  1.0
  K  K6  1  0.082  0.470  0.750  1.0
  K  K7  1  0.470  0.082  0.250  1.0
  V  V8  1  0.226  0.774  0.476  1.0
  V  V9  1  0.774  0.226  0.524  1.0
  V  V10  1  0.226  0.774  0.024  1.0
  V  V11  1  0.774  0.226  0.976  1.0
  O  O12  1  0.031  0.718  0.535  1.0
  O  O13  1  0.718  0.031  0.465  1.0
  O  O14  1  0.031  0.718  0.965  1.0
  O  O15  1  0.718  0.031  0.035  1.0
  O  O16  1  0.969  0.282  0.465  1.0
  O  O17  1  0.282  0.969  0.535  1.0
  O  O18  1  0.969  0.282  0.035  1.0
  O  O19  1  0.282  0.969  0.965  1.0
  O  O20  1  0.352  0.648  0.555  1.0
  O  O21  1  0.648  0.352  0.445  1.0
  O  O22  1  0.352  0.648  0.945  1.0
  O  O23  1  0.648  0.352  0.055  1.0
  O  O24  1  0.233  0.767  0.250  1.0
  O  O25  1  0.767  0.233  0.750  1.0
  O  O26  1  0.160  0.304  0.250  1.0
  O  O27  1  0.304  0.160  0.750  1.0
  O  O28  1  0.840  0.696  0.750  1.0
  O  O29  1  0.696  0.840  0.250  1.0
[/CIF]
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The compound described by K4V2O9 crystallizes in the orthorhombic Cmcm space group. There are three inequivalent K sites. In the first K site, K(1) is bonded to one O(3), two equivalent O(4), and four equivalent O(2) atoms to form KO7 pentagonal bipyramids that share corners with two equivalent V(1)O4 tetrahedra, edges with two equivalent K(1)O7 pentagonal bipyramids, and edges with two equivalent V(1)O4 tetrahedra. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(4), and four equivalent O(1) atoms. In the third K site, K(3) is bonded in a 9-coordinate geometry to one O(3), two equivalent O(2), two equivalent O(4), and four equivalent O(1) atoms. V(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form VO4 tetrahedra that share  a cornercorner with one K(1)O7 pentagonal bipyramid,  a cornercorner with one V(1)O4 tetrahedra, and  an edgeedge with one K(1)O7 pentagonal bipyramid. There are four inequivalent O sites. In the first O site, O(2) is bonded in a distorted single-bond geometry to two equivalent K(1), two equivalent K(3), and one V(1) atom. In the second O site, O(3) is bonded in a distorted linear geometry to one K(1), one K(2), two equivalent K(3), and two equivalent V(1) atoms. In the third O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one K(2), and two equivalent K(3) atoms. In the fourth O site, O(1) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(3), and one V(1) atom. is represented by the CIF card [CIF]
data_K4V2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.401
_cell_length_b   8.401
_cell_length_c   8.109
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   96.437
_symmetry_Int_Tables_number   1
_cell_volume   568.713
_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
  K  K0  1  0.465  0.535  0.250  1.0
  K  K1  1  0.535  0.465  0.750  1.0
  K  K2  1  0.986  0.014  0.250  1.0
  K  K3  1  0.014  0.986  0.750  1.0
  K  K4  1  0.918  0.530  0.250  1.0
  K  K5  1  0.530  0.918  0.750  1.0
  K  K6  1  0.082  0.470  0.750  1.0
  K  K7  1  0.470  0.082  0.250  1.0
  V  V8  1  0.226  0.774  0.476  1.0
  V  V9  1  0.774  0.226  0.524  1.0
  V  V10  1  0.226  0.774  0.024  1.0
  V  V11  1  0.774  0.226  0.976  1.0
  O  O12  1  0.031  0.718  0.535  1.0
  O  O13  1  0.718  0.031  0.465  1.0
  O  O14  1  0.031  0.718  0.965  1.0
  O  O15  1  0.718  0.031  0.035  1.0
  O  O16  1  0.969  0.282  0.465  1.0
  O  O17  1  0.282  0.969  0.535  1.0
  O  O18  1  0.969  0.282  0.035  1.0
  O  O19  1  0.282  0.969  0.965  1.0
  O  O20  1  0.352  0.648  0.555  1.0
  O  O21  1  0.648  0.352  0.445  1.0
  O  O22  1  0.352  0.648  0.945  1.0
  O  O23  1  0.648  0.352  0.055  1.0
  O  O24  1  0.233  0.767  0.250  1.0
  O  O25  1  0.767  0.233  0.750  1.0
  O  O26  1  0.160  0.304  0.250  1.0
  O  O27  1  0.304  0.160  0.750  1.0
  O  O28  1  0.840  0.696  0.750  1.0
  O  O29  1  0.696  0.840  0.250  1.0
[/CIF]
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