The material described by CaMgSi2O6 is Esseneite structured and crystallizes in the monoclinic C2/c space group. Ca(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form CaO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra and edges with two equivalent Ca(1)O6 octahedra. Mg(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(3) atoms. Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-66°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one Mg(1), and one Si(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(1), one Mg(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaMg(SiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.039
_cell_length_b   7.039
_cell_length_c   5.518
_cell_angle_alpha   75.833
_cell_angle_beta   75.833
_cell_angle_gamma   88.638
_symmetry_Int_Tables_number   1
_cell_volume   256.821
_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  0.108  0.892  0.750  1.0
  Ca  Ca1  1  0.892  0.108  0.250  1.0
  Mg  Mg2  1  0.241  0.759  0.250  1.0
  Mg  Mg3  1  0.759  0.241  0.750  1.0
  Si  Si4  1  0.783  0.618  0.290  1.0
  Si  Si5  1  0.382  0.217  0.210  1.0
  Si  Si6  1  0.217  0.382  0.710  1.0
  Si  Si7  1  0.618  0.783  0.790  1.0
  O  O8  1  0.835  0.392  0.391  1.0
  O  O9  1  0.320  0.365  0.957  1.0
  O  O10  1  0.635  0.680  0.543  1.0
  O  O11  1  0.223  0.030  0.317  1.0
  O  O12  1  0.970  0.777  0.183  1.0
  O  O13  1  0.608  0.165  0.109  1.0
  O  O14  1  0.030  0.223  0.817  1.0
  O  O15  1  0.392  0.835  0.891  1.0
  O  O16  1  0.365  0.320  0.457  1.0
  O  O17  1  0.165  0.608  0.609  1.0
  O  O18  1  0.777  0.970  0.683  1.0
  O  O19  1  0.680  0.635  0.043  1.0
[/CIF]
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The material described by CaMgSi2O6 is Esseneite structured and crystallizes in the monoclinic C2/c space group. Ca(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form CaO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra and edges with two equivalent Ca(1)O6 octahedra. Mg(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(3) atoms. Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-66°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one Mg(1), and one Si(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(1), one Mg(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaMg(SiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.039
_cell_length_b   7.039
_cell_length_c   5.518
_cell_angle_alpha   75.833
_cell_angle_beta   75.833
_cell_angle_gamma   88.638
_symmetry_Int_Tables_number   1
_cell_volume   256.821
_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  0.108  0.892  0.750  1.0
  Ca  Ca1  1  0.892  0.108  0.250  1.0
  Mg  Mg2  1  0.241  0.759  0.250  1.0
  Mg  Mg3  1  0.759  0.241  0.750  1.0
  Si  Si4  1  0.783  0.618  0.290  1.0
  Si  Si5  1  0.382  0.217  0.210  1.0
  Si  Si6  1  0.217  0.382  0.710  1.0
  Si  Si7  1  0.618  0.783  0.790  1.0
  O  O8  1  0.835  0.392  0.391  1.0
  O  O9  1  0.320  0.365  0.957  1.0
  O  O10  1  0.635  0.680  0.543  1.0
  O  O11  1  0.223  0.030  0.317  1.0
  O  O12  1  0.970  0.777  0.183  1.0
  O  O13  1  0.608  0.165  0.109  1.0
  O  O14  1  0.030  0.223  0.817  1.0
  O  O15  1  0.392  0.835  0.891  1.0
  O  O16  1  0.365  0.320  0.457  1.0
  O  O17  1  0.165  0.608  0.609  1.0
  O  O18  1  0.777  0.970  0.683  1.0
  O  O19  1  0.680  0.635  0.043  1.0
[/CIF]
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