The material described by MgU2(SiO9)2 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a linear geometry to two equivalent O(4) and four equivalent O(6) atoms. U(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), and four equivalent O(5) atoms. Si(1) is bonded in a tetrahedral geometry to one O(3), one O(4), and two equivalent O(5) atoms. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one U(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one U(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one U(1) and one Si(1) atom. In the fourth O site, O(4) is bonded in a linear geometry to one Mg(1) and one Si(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent U(1) and one Si(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Mg(1) and one O(7) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to two equivalent O(6) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgU2(SiO9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.071
_cell_length_b   9.071
_cell_length_c   6.803
_cell_angle_alpha   79.867
_cell_angle_beta   79.867
_cell_angle_gamma   45.077
_symmetry_Int_Tables_number   1
_cell_volume   389.127
_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  0.000  0.000  0.500  1.0
  U  U1  1  0.253  0.253  0.857  1.0
  U  U2  1  0.747  0.747  0.143  1.0
  Si  Si3  1  0.793  0.793  0.653  1.0
  Si  Si4  1  0.207  0.207  0.347  1.0
  O  O5  1  0.362  0.362  0.844  1.0
  O  O6  1  0.638  0.638  0.156  1.0
  O  O7  1  0.142  0.142  0.910  1.0
  O  O8  1  0.858  0.858  0.090  1.0
  O  O9  1  0.747  0.747  0.461  1.0
  O  O10  1  0.253  0.253  0.539  1.0
  O  O11  1  0.889  0.889  0.577  1.0
  O  O12  1  0.111  0.111  0.423  1.0
  O  O13  1  0.939  0.584  0.811  1.0
  O  O14  1  0.584  0.939  0.811  1.0
  O  O15  1  0.061  0.416  0.189  1.0
  O  O16  1  0.416  0.061  0.189  1.0
  O  O17  1  0.328  0.644  0.313  1.0
  O  O18  1  0.644  0.328  0.313  1.0
  O  O19  1  0.672  0.356  0.687  1.0
  O  O20  1  0.356  0.672  0.687  1.0
  O  O21  1  0.547  0.547  0.731  1.0
  O  O22  1  0.453  0.453  0.269  1.0
[/CIF]
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The material described by MgU2(SiO9)2 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a linear geometry to two equivalent O(4) and four equivalent O(6) atoms. U(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), and four equivalent O(5) atoms. Si(1) is bonded in a tetrahedral geometry to one O(3), one O(4), and two equivalent O(5) atoms. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one U(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one U(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one U(1) and one Si(1) atom. In the fourth O site, O(4) is bonded in a linear geometry to one Mg(1) and one Si(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent U(1) and one Si(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Mg(1) and one O(7) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to two equivalent O(6) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgU2(SiO9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.071
_cell_length_b   9.071
_cell_length_c   6.803
_cell_angle_alpha   79.867
_cell_angle_beta   79.867
_cell_angle_gamma   45.077
_symmetry_Int_Tables_number   1
_cell_volume   389.127
_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  0.000  0.000  0.500  1.0
  U  U1  1  0.253  0.253  0.857  1.0
  U  U2  1  0.747  0.747  0.143  1.0
  Si  Si3  1  0.793  0.793  0.653  1.0
  Si  Si4  1  0.207  0.207  0.347  1.0
  O  O5  1  0.362  0.362  0.844  1.0
  O  O6  1  0.638  0.638  0.156  1.0
  O  O7  1  0.142  0.142  0.910  1.0
  O  O8  1  0.858  0.858  0.090  1.0
  O  O9  1  0.747  0.747  0.461  1.0
  O  O10  1  0.253  0.253  0.539  1.0
  O  O11  1  0.889  0.889  0.577  1.0
  O  O12  1  0.111  0.111  0.423  1.0
  O  O13  1  0.939  0.584  0.811  1.0
  O  O14  1  0.584  0.939  0.811  1.0
  O  O15  1  0.061  0.416  0.189  1.0
  O  O16  1  0.416  0.061  0.189  1.0
  O  O17  1  0.328  0.644  0.313  1.0
  O  O18  1  0.644  0.328  0.313  1.0
  O  O19  1  0.672  0.356  0.687  1.0
  O  O20  1  0.356  0.672  0.687  1.0
  O  O21  1  0.547  0.547  0.731  1.0
  O  O22  1  0.453  0.453  0.269  1.0
[/CIF]
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