The structure described by CaMg6SiO8 is alpha Po-derived structured and crystallizes in the tetragonal P4/mmm 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 two equivalent Si(1)O6 octahedra, corners with four equivalent Ca(1)O6 octahedra, edges with four equivalent Mg(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with four equivalent Mg(1)O6 octahedra, edges with four equivalent Ca(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. In the second Mg site, Mg(2) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, edges with four equivalent Si(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. In the third Mg site, Mg(3) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form MgO6 octahedra that share corners with six equivalent Mg(3)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Si(1)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. Si(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form SiO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with four equivalent Si(1)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), four equivalent Mg(3), and one Si(1) atom to form OCaMg4Si octahedra that share corners with six equivalent O(1)CaMg4Si octahedra, edges with four equivalent O(3)Ca2Mg4 octahedra, edges with four equivalent O(4)Mg4Si2 octahedra, and edges with four equivalent O(2)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second O site, O(2) is bonded to one Mg(1), one Mg(2), and four equivalent Mg(3) atoms to form OMg6 octahedra that share corners with six equivalent O(2)Mg6 octahedra, edges with four equivalent O(3)Ca2Mg4 octahedra, edges with four equivalent O(1)CaMg4Si octahedra, and edges with four equivalent O(4)Mg4Si2 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the third O site, O(3) is bonded to two equivalent Ca(1), two equivalent Mg(1), and two equivalent Mg(3) atoms to form OCa2Mg4 octahedra that share corners with two equivalent O(4)Mg4Si2 octahedra, corners with four equivalent O(3)Ca2Mg4 octahedra, edges with four equivalent O(3)Ca2Mg4 octahedra, edges with four equivalent O(1)CaMg4Si octahedra, and edges with four equivalent O(2)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the fourth O site, O(4) is bonded to two equivalent Mg(2), two equivalent Mg(3), and two equivalent Si(1) atoms to form OMg4Si2 octahedra that share corners with two equivalent O(3)Ca2Mg4 octahedra, corners with four equivalent O(4)Mg4Si2 octahedra, edges with four equivalent O(1)CaMg4Si octahedra, edges with four equivalent O(4)Mg4Si2 octahedra, and edges with four equivalent O(2)Mg6 octahedra. The corner-sharing octahedra are not tilted. is represented by the CIF file [CIF]
data_CaMg6SiO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.743
_cell_length_b   4.430
_cell_length_c   4.430
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   171.583
_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
  Ca  Ca0  1  0.000  0.000  0.000  1.0
  Mg  Mg1  1  0.000  0.500  0.500  1.0
  Mg  Mg2  1  0.500  0.500  0.500  1.0
  Mg  Mg3  1  0.254  0.000  0.500  1.0
  Mg  Mg4  1  0.746  0.000  0.500  1.0
  Mg  Mg5  1  0.254  0.500  0.000  1.0
  Mg  Mg6  1  0.746  0.500  0.000  1.0
  Si  Si7  1  0.500  0.000  0.000  1.0
  O  O8  1  0.257  0.000  0.000  1.0
  O  O9  1  0.743  0.000  0.000  1.0
  O  O10  1  0.251  0.500  0.500  1.0
  O  O11  1  0.749  0.500  0.500  1.0
  O  O12  1  0.000  0.000  0.500  1.0
  O  O13  1  0.500  0.000  0.500  1.0
  O  O14  1  0.000  0.500  0.000  1.0
  O  O15  1  0.500  0.500  0.000  1.0
[/CIF]
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The structure described by CaMg6SiO8 is alpha Po-derived structured and crystallizes in the tetragonal P4/mmm 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 two equivalent Si(1)O6 octahedra, corners with four equivalent Ca(1)O6 octahedra, edges with four equivalent Mg(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with four equivalent Mg(1)O6 octahedra, edges with four equivalent Ca(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. In the second Mg site, Mg(2) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, edges with four equivalent Si(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. In the third Mg site, Mg(3) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form MgO6 octahedra that share corners with six equivalent Mg(3)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Si(1)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. Si(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form SiO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with four equivalent Si(1)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), four equivalent Mg(3), and one Si(1) atom to form OCaMg4Si octahedra that share corners with six equivalent O(1)CaMg4Si octahedra, edges with four equivalent O(3)Ca2Mg4 octahedra, edges with four equivalent O(4)Mg4Si2 octahedra, and edges with four equivalent O(2)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second O site, O(2) is bonded to one Mg(1), one Mg(2), and four equivalent Mg(3) atoms to form OMg6 octahedra that share corners with six equivalent O(2)Mg6 octahedra, edges with four equivalent O(3)Ca2Mg4 octahedra, edges with four equivalent O(1)CaMg4Si octahedra, and edges with four equivalent O(4)Mg4Si2 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the third O site, O(3) is bonded to two equivalent Ca(1), two equivalent Mg(1), and two equivalent Mg(3) atoms to form OCa2Mg4 octahedra that share corners with two equivalent O(4)Mg4Si2 octahedra, corners with four equivalent O(3)Ca2Mg4 octahedra, edges with four equivalent O(3)Ca2Mg4 octahedra, edges with four equivalent O(1)CaMg4Si octahedra, and edges with four equivalent O(2)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the fourth O site, O(4) is bonded to two equivalent Mg(2), two equivalent Mg(3), and two equivalent Si(1) atoms to form OMg4Si2 octahedra that share corners with two equivalent O(3)Ca2Mg4 octahedra, corners with four equivalent O(4)Mg4Si2 octahedra, edges with four equivalent O(1)CaMg4Si octahedra, edges with four equivalent O(4)Mg4Si2 octahedra, and edges with four equivalent O(2)Mg6 octahedra. The corner-sharing octahedra are not tilted. is represented by the CIF file [CIF]
data_CaMg6SiO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.743
_cell_length_b   4.430
_cell_length_c   4.430
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   171.583
_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
  Ca  Ca0  1  0.000  0.000  0.000  1.0
  Mg  Mg1  1  0.000  0.500  0.500  1.0
  Mg  Mg2  1  0.500  0.500  0.500  1.0
  Mg  Mg3  1  0.254  0.000  0.500  1.0
  Mg  Mg4  1  0.746  0.000  0.500  1.0
  Mg  Mg5  1  0.254  0.500  0.000  1.0
  Mg  Mg6  1  0.746  0.500  0.000  1.0
  Si  Si7  1  0.500  0.000  0.000  1.0
  O  O8  1  0.257  0.000  0.000  1.0
  O  O9  1  0.743  0.000  0.000  1.0
  O  O10  1  0.251  0.500  0.500  1.0
  O  O11  1  0.749  0.500  0.500  1.0
  O  O12  1  0.000  0.000  0.500  1.0
  O  O13  1  0.500  0.000  0.500  1.0
  O  O14  1  0.000  0.500  0.000  1.0
  O  O15  1  0.500  0.500  0.000  1.0
[/CIF]
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