The compound described by NaCrGe2O6 is Esseneite structured and crystallizes in the monoclinic C2/c space group. Na(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Cr(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form CrO6 octahedra that share corners with six equivalent Ge(1)O4 tetrahedra and edges with two equivalent Cr(1)O6 octahedra. Ge(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form GeO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra and corners with two equivalent Ge(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 39-62°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Na(1) and two equivalent Ge(1) atoms. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Na(1), one Cr(1), and one Ge(1) atom. In the third O site, O(3) is bonded to one Na(1), two equivalent Cr(1), and one Ge(1) atom to form a mixture of distorted corner and edge-sharing ONaCr2Ge tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_NaCr(GeO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.555
_cell_length_b   6.755
_cell_length_c   6.755
_cell_angle_alpha   83.100
_cell_angle_beta   76.810
_cell_angle_gamma   76.810
_symmetry_Int_Tables_number   1
_cell_volume   239.673
_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
  Na  Na0  1  0.250  0.697  0.303  1.0
  Na  Na1  1  0.750  0.303  0.697  1.0
  Cr  Cr2  1  0.750  0.911  0.089  1.0
  Cr  Cr3  1  0.250  0.089  0.911  1.0
  Ge  Ge4  1  0.774  0.386  0.194  1.0
  Ge  Ge5  1  0.726  0.806  0.614  1.0
  Ge  Ge6  1  0.226  0.614  0.806  1.0
  Ge  Ge7  1  0.274  0.194  0.386  1.0
  O  O8  1  0.493  0.351  0.375  1.0
  O  O9  1  0.007  0.625  0.649  1.0
  O  O10  1  0.507  0.649  0.625  1.0
  O  O11  1  0.993  0.375  0.351  1.0
  O  O12  1  0.190  0.086  0.632  1.0
  O  O13  1  0.310  0.368  0.914  1.0
  O  O14  1  0.810  0.914  0.368  1.0
  O  O15  1  0.690  0.632  0.086  1.0
  O  O16  1  0.871  0.188  0.023  1.0
  O  O17  1  0.629  0.977  0.812  1.0
  O  O18  1  0.129  0.812  0.977  1.0
  O  O19  1  0.371  0.023  0.188  1.0
[/CIF]
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The compound described by NaCrGe2O6 is Esseneite structured and crystallizes in the monoclinic C2/c space group. Na(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Cr(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form CrO6 octahedra that share corners with six equivalent Ge(1)O4 tetrahedra and edges with two equivalent Cr(1)O6 octahedra. Ge(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form GeO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra and corners with two equivalent Ge(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 39-62°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Na(1) and two equivalent Ge(1) atoms. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Na(1), one Cr(1), and one Ge(1) atom. In the third O site, O(3) is bonded to one Na(1), two equivalent Cr(1), and one Ge(1) atom to form a mixture of distorted corner and edge-sharing ONaCr2Ge tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_NaCr(GeO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.555
_cell_length_b   6.755
_cell_length_c   6.755
_cell_angle_alpha   83.100
_cell_angle_beta   76.810
_cell_angle_gamma   76.810
_symmetry_Int_Tables_number   1
_cell_volume   239.673
_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
  Na  Na0  1  0.250  0.697  0.303  1.0
  Na  Na1  1  0.750  0.303  0.697  1.0
  Cr  Cr2  1  0.750  0.911  0.089  1.0
  Cr  Cr3  1  0.250  0.089  0.911  1.0
  Ge  Ge4  1  0.774  0.386  0.194  1.0
  Ge  Ge5  1  0.726  0.806  0.614  1.0
  Ge  Ge6  1  0.226  0.614  0.806  1.0
  Ge  Ge7  1  0.274  0.194  0.386  1.0
  O  O8  1  0.493  0.351  0.375  1.0
  O  O9  1  0.007  0.625  0.649  1.0
  O  O10  1  0.507  0.649  0.625  1.0
  O  O11  1  0.993  0.375  0.351  1.0
  O  O12  1  0.190  0.086  0.632  1.0
  O  O13  1  0.310  0.368  0.914  1.0
  O  O14  1  0.810  0.914  0.368  1.0
  O  O15  1  0.690  0.632  0.086  1.0
  O  O16  1  0.871  0.188  0.023  1.0
  O  O17  1  0.629  0.977  0.812  1.0
  O  O18  1  0.129  0.812  0.977  1.0
  O  O19  1  0.371  0.023  0.188  1.0
[/CIF]
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