The material described by Sr2CuGe2O7 crystallizes in the tetragonal P-42_1m space group. Sr(1) is bonded in a 8-coordinate geometry to one O(3), three equivalent O(2), and four equivalent O(1) atoms. Cu(1) is bonded to four equivalent O(1) atoms to form CuO4 tetrahedra that share corners with four equivalent Ge(1)O4 tetrahedra. Ge(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form GeO4 tetrahedra that share  a cornercorner with one Ge(1)O4 tetrahedra and corners with two equivalent Cu(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Cu(1), and one Ge(1) atom. In the second O site, O(2) is bonded to three equivalent Sr(1) and one Ge(1) atom to form distorted OSr3Ge tetrahedra that share corners with two equivalent O(3)Sr2Ge2 tetrahedra, corners with four equivalent O(2)Sr3Ge tetrahedra,  an edgeedge with one O(3)Sr2Ge2 tetrahedra, and  an edgeedge with one O(2)Sr3Ge tetrahedra. In the third O site, O(3) is bonded to two equivalent Sr(1) and two equivalent Ge(1) atoms to form a mixture of distorted edge and corner-sharing OSr2Ge2 tetrahedra. is represented by the CIF file [CIF]
data_Sr2CuGe2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.385
_cell_length_b   8.385
_cell_length_c   5.281
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   371.272
_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
  Sr  Sr0  1  0.665  0.165  0.989  1.0
  Sr  Sr1  1  0.835  0.665  0.011  1.0
  Sr  Sr2  1  0.165  0.335  0.011  1.0
  Sr  Sr3  1  0.335  0.835  0.989  1.0
  Cu  Cu4  1  0.000  0.000  0.500  1.0
  Cu  Cu5  1  0.500  0.500  0.500  1.0
  Ge  Ge6  1  0.859  0.359  0.532  1.0
  Ge  Ge7  1  0.141  0.641  0.532  1.0
  Ge  Ge8  1  0.641  0.859  0.468  1.0
  Ge  Ge9  1  0.359  0.141  0.468  1.0
  O  O10  1  0.681  0.414  0.688  1.0
  O  O11  1  0.319  0.586  0.688  1.0
  O  O12  1  0.414  0.319  0.312  1.0
  O  O13  1  0.586  0.681  0.312  1.0
  O  O14  1  0.914  0.181  0.688  1.0
  O  O15  1  0.819  0.914  0.312  1.0
  O  O16  1  0.181  0.086  0.312  1.0
  O  O17  1  0.086  0.819  0.688  1.0
  O  O18  1  0.866  0.366  0.203  1.0
  O  O19  1  0.634  0.866  0.797  1.0
  O  O20  1  0.000  0.500  0.674  1.0
  O  O21  1  0.500  0.000  0.326  1.0
  O  O22  1  0.134  0.634  0.203  1.0
  O  O23  1  0.366  0.134  0.797  1.0
[/CIF]
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The material described by Sr2CuGe2O7 crystallizes in the tetragonal P-42_1m space group. Sr(1) is bonded in a 8-coordinate geometry to one O(3), three equivalent O(2), and four equivalent O(1) atoms. Cu(1) is bonded to four equivalent O(1) atoms to form CuO4 tetrahedra that share corners with four equivalent Ge(1)O4 tetrahedra. Ge(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form GeO4 tetrahedra that share  a cornercorner with one Ge(1)O4 tetrahedra and corners with two equivalent Cu(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Cu(1), and one Ge(1) atom. In the second O site, O(2) is bonded to three equivalent Sr(1) and one Ge(1) atom to form distorted OSr3Ge tetrahedra that share corners with two equivalent O(3)Sr2Ge2 tetrahedra, corners with four equivalent O(2)Sr3Ge tetrahedra,  an edgeedge with one O(3)Sr2Ge2 tetrahedra, and  an edgeedge with one O(2)Sr3Ge tetrahedra. In the third O site, O(3) is bonded to two equivalent Sr(1) and two equivalent Ge(1) atoms to form a mixture of distorted edge and corner-sharing OSr2Ge2 tetrahedra. is represented by the CIF file [CIF]
data_Sr2CuGe2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.385
_cell_length_b   8.385
_cell_length_c   5.281
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   371.272
_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
  Sr  Sr0  1  0.665  0.165  0.989  1.0
  Sr  Sr1  1  0.835  0.665  0.011  1.0
  Sr  Sr2  1  0.165  0.335  0.011  1.0
  Sr  Sr3  1  0.335  0.835  0.989  1.0
  Cu  Cu4  1  0.000  0.000  0.500  1.0
  Cu  Cu5  1  0.500  0.500  0.500  1.0
  Ge  Ge6  1  0.859  0.359  0.532  1.0
  Ge  Ge7  1  0.141  0.641  0.532  1.0
  Ge  Ge8  1  0.641  0.859  0.468  1.0
  Ge  Ge9  1  0.359  0.141  0.468  1.0
  O  O10  1  0.681  0.414  0.688  1.0
  O  O11  1  0.319  0.586  0.688  1.0
  O  O12  1  0.414  0.319  0.312  1.0
  O  O13  1  0.586  0.681  0.312  1.0
  O  O14  1  0.914  0.181  0.688  1.0
  O  O15  1  0.819  0.914  0.312  1.0
  O  O16  1  0.181  0.086  0.312  1.0
  O  O17  1  0.086  0.819  0.688  1.0
  O  O18  1  0.866  0.366  0.203  1.0
  O  O19  1  0.634  0.866  0.797  1.0
  O  O20  1  0.000  0.500  0.674  1.0
  O  O21  1  0.500  0.000  0.326  1.0
  O  O22  1  0.134  0.634  0.203  1.0
  O  O23  1  0.366  0.134  0.797  1.0
[/CIF]
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