The structure described by BaSrCaMg(SiO4)2 crystallizes in the trigonal P3m1 space group. Ba(1) is bonded to three equivalent O(1), three equivalent O(2), three equivalent O(3), and three equivalent O(4) atoms to form BaO12 cuboctahedra that share edges with six equivalent Ba(1)O12 cuboctahedra, edges with three equivalent Si(1)O4 tetrahedra, edges with three equivalent Si(2)O4 tetrahedra, and faces with two equivalent Mg(1)O6 octahedra. Sr(1) is bonded in a 10-coordinate geometry to one O(1), three equivalent O(3), and six equivalent O(4) atoms. Ca(1) is bonded in a 10-coordinate geometry to one O(2), three equivalent O(4), and six equivalent O(3) atoms. Mg(1) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form MgO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1) and three equivalent O(3) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and edges with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 13°. In the second Si site, Si(2) is bonded to one O(2) and three equivalent O(4) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and edges with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 13°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to three equivalent Ba(1), one Sr(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to three equivalent Ba(1), one Ca(1), and one Si(2) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to one Ba(1), one Sr(1), two equivalent Ca(1), one Mg(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Ba(1), two equivalent Sr(1), one Ca(1), one Mg(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaSrCaMg(SiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.532
_cell_length_b   5.532
_cell_length_c   6.991
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   185.258
_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
  Ba  Ba0  1  0.333  0.667  0.499  1.0
  Sr  Sr1  1  0.667  0.333  0.841  1.0
  Ca  Ca2  1  0.000  0.000  0.167  1.0
  Mg  Mg3  1  0.333  0.667  0.000  1.0
  Si  Si4  1  0.667  0.333  0.272  1.0
  Si  Si5  1  0.000  0.000  0.726  1.0
  O  O6  1  0.667  0.333  0.503  1.0
  O  O7  1  0.000  0.000  0.493  1.0
  O  O8  1  0.508  0.492  0.178  1.0
  O  O9  1  0.508  0.016  0.178  1.0
  O  O10  1  0.984  0.492  0.178  1.0
  O  O11  1  0.158  0.842  0.822  1.0
  O  O12  1  0.158  0.316  0.822  1.0
  O  O13  1  0.684  0.842  0.822  1.0
[/CIF]
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The structure described by BaSrCaMg(SiO4)2 crystallizes in the trigonal P3m1 space group. Ba(1) is bonded to three equivalent O(1), three equivalent O(2), three equivalent O(3), and three equivalent O(4) atoms to form BaO12 cuboctahedra that share edges with six equivalent Ba(1)O12 cuboctahedra, edges with three equivalent Si(1)O4 tetrahedra, edges with three equivalent Si(2)O4 tetrahedra, and faces with two equivalent Mg(1)O6 octahedra. Sr(1) is bonded in a 10-coordinate geometry to one O(1), three equivalent O(3), and six equivalent O(4) atoms. Ca(1) is bonded in a 10-coordinate geometry to one O(2), three equivalent O(4), and six equivalent O(3) atoms. Mg(1) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form MgO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1) and three equivalent O(3) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and edges with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 13°. In the second Si site, Si(2) is bonded to one O(2) and three equivalent O(4) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and edges with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 13°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to three equivalent Ba(1), one Sr(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to three equivalent Ba(1), one Ca(1), and one Si(2) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to one Ba(1), one Sr(1), two equivalent Ca(1), one Mg(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Ba(1), two equivalent Sr(1), one Ca(1), one Mg(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaSrCaMg(SiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.532
_cell_length_b   5.532
_cell_length_c   6.991
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   185.258
_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
  Ba  Ba0  1  0.333  0.667  0.499  1.0
  Sr  Sr1  1  0.667  0.333  0.841  1.0
  Ca  Ca2  1  0.000  0.000  0.167  1.0
  Mg  Mg3  1  0.333  0.667  0.000  1.0
  Si  Si4  1  0.667  0.333  0.272  1.0
  Si  Si5  1  0.000  0.000  0.726  1.0
  O  O6  1  0.667  0.333  0.503  1.0
  O  O7  1  0.000  0.000  0.493  1.0
  O  O8  1  0.508  0.492  0.178  1.0
  O  O9  1  0.508  0.016  0.178  1.0
  O  O10  1  0.984  0.492  0.178  1.0
  O  O11  1  0.158  0.842  0.822  1.0
  O  O12  1  0.158  0.316  0.822  1.0
  O  O13  1  0.684  0.842  0.822  1.0
[/CIF]
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