The crystal structure described by Mg2As2O7 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form distorted MgO6 pentagonal pyramids that share corners with six equivalent As(1)O4 tetrahedra and edges with three equivalent Mg(1)O6 pentagonal pyramids. As(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form AsO4 tetrahedra that share corners with six equivalent Mg(1)O6 pentagonal pyramids and  a cornercorner with one As(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one As(1) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent As(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one As(1) atom. is represented by the CIF card [CIF]
data_Mg2As2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.783
_cell_length_b   5.379
_cell_length_c   5.379
_cell_angle_alpha   105.270
_cell_angle_beta   97.862
_cell_angle_gamma   97.863
_symmetry_Int_Tables_number   1
_cell_volume   130.064
_cell_formula_units_Z   1
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
  Mg  Mg0  1  0.500  0.689  0.311  1.0
  Mg  Mg1  1  0.500  0.311  0.689  1.0
  As  As2  1  0.099  0.764  0.764  1.0
  As  As3  1  0.901  0.236  0.236  1.0
  O  O4  1  0.291  0.930  0.601  1.0
  O  O5  1  0.709  0.399  0.070  1.0
  O  O6  1  0.709  0.070  0.399  1.0
  O  O7  1  0.291  0.601  0.930  1.0
  O  O8  1  0.000  0.000  0.000  1.0
  O  O9  1  0.774  0.596  0.596  1.0
  O  O10  1  0.226  0.404  0.404  1.0
[/CIF]
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The crystal structure described by Mg2As2O7 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form distorted MgO6 pentagonal pyramids that share corners with six equivalent As(1)O4 tetrahedra and edges with three equivalent Mg(1)O6 pentagonal pyramids. As(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form AsO4 tetrahedra that share corners with six equivalent Mg(1)O6 pentagonal pyramids and  a cornercorner with one As(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one As(1) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent As(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one As(1) atom. is represented by the CIF card [CIF]
data_Mg2As2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.783
_cell_length_b   5.379
_cell_length_c   5.379
_cell_angle_alpha   105.270
_cell_angle_beta   97.862
_cell_angle_gamma   97.863
_symmetry_Int_Tables_number   1
_cell_volume   130.064
_cell_formula_units_Z   1
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
  Mg  Mg0  1  0.500  0.689  0.311  1.0
  Mg  Mg1  1  0.500  0.311  0.689  1.0
  As  As2  1  0.099  0.764  0.764  1.0
  As  As3  1  0.901  0.236  0.236  1.0
  O  O4  1  0.291  0.930  0.601  1.0
  O  O5  1  0.709  0.399  0.070  1.0
  O  O6  1  0.709  0.070  0.399  1.0
  O  O7  1  0.291  0.601  0.930  1.0
  O  O8  1  0.000  0.000  0.000  1.0
  O  O9  1  0.774  0.596  0.596  1.0
  O  O10  1  0.226  0.404  0.404  1.0
[/CIF]
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