The compound described by MgIr3Si7 crystallizes in the trigonal R-3c space group. Mg(1) is bonded in a 18-coordinate geometry to six equivalent Ir(1) and twelve equivalent Si(1) atoms. Ir(1) is bonded in a 9-coordinate geometry to two equivalent Mg(1), one Si(2), and six equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(2) is bonded in a distorted trigonal planar geometry to three equivalent Ir(1) atoms. In the second Si site, Si(1) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and three equivalent Ir(1) atoms. is represented by the CIF card [CIF]
data_MgSi7Ir3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.928
_cell_length_b   7.928
_cell_length_c   7.928
_cell_angle_alpha   56.790
_cell_angle_beta   56.790
_cell_angle_gamma   56.790
_symmetry_Int_Tables_number   1
_cell_volume   326.253
_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
  Mg  Mg0  1  0.500  0.500  0.500  1.0
  Mg  Mg1  1  1.000  0.000  0.000  1.0
  Si  Si2  1  0.851  0.063  0.674  1.0
  Si  Si3  1  0.674  0.851  0.063  1.0
  Si  Si4  1  0.063  0.674  0.851  1.0
  Si  Si5  1  0.649  0.826  0.437  1.0
  Si  Si6  1  0.250  0.250  0.250  1.0
  Si  Si7  1  0.750  0.750  0.750  1.0
  Si  Si8  1  0.174  0.563  0.351  1.0
  Si  Si9  1  0.563  0.351  0.174  1.0
  Si  Si10  1  0.351  0.174  0.563  1.0
  Si  Si11  1  0.937  0.326  0.149  1.0
  Si  Si12  1  0.326  0.149  0.937  1.0
  Si  Si13  1  0.149  0.937  0.326  1.0
  Si  Si14  1  0.826  0.437  0.649  1.0
  Si  Si15  1  0.437  0.649  0.826  1.0
  Ir  Ir16  1  0.750  0.074  0.426  1.0
  Ir  Ir17  1  0.426  0.750  0.074  1.0
  Ir  Ir18  1  0.074  0.426  0.750  1.0
  Ir  Ir19  1  0.250  0.926  0.574  1.0
  Ir  Ir20  1  0.574  0.250  0.926  1.0
  Ir  Ir21  1  0.926  0.574  0.250  1.0
[/CIF]
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The compound described by MgIr3Si7 crystallizes in the trigonal R-3c space group. Mg(1) is bonded in a 18-coordinate geometry to six equivalent Ir(1) and twelve equivalent Si(1) atoms. Ir(1) is bonded in a 9-coordinate geometry to two equivalent Mg(1), one Si(2), and six equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(2) is bonded in a distorted trigonal planar geometry to three equivalent Ir(1) atoms. In the second Si site, Si(1) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and three equivalent Ir(1) atoms. is represented by the CIF card [CIF]
data_MgSi7Ir3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.928
_cell_length_b   7.928
_cell_length_c   7.928
_cell_angle_alpha   56.790
_cell_angle_beta   56.790
_cell_angle_gamma   56.790
_symmetry_Int_Tables_number   1
_cell_volume   326.253
_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
  Mg  Mg0  1  0.500  0.500  0.500  1.0
  Mg  Mg1  1  1.000  0.000  0.000  1.0
  Si  Si2  1  0.851  0.063  0.674  1.0
  Si  Si3  1  0.674  0.851  0.063  1.0
  Si  Si4  1  0.063  0.674  0.851  1.0
  Si  Si5  1  0.649  0.826  0.437  1.0
  Si  Si6  1  0.250  0.250  0.250  1.0
  Si  Si7  1  0.750  0.750  0.750  1.0
  Si  Si8  1  0.174  0.563  0.351  1.0
  Si  Si9  1  0.563  0.351  0.174  1.0
  Si  Si10  1  0.351  0.174  0.563  1.0
  Si  Si11  1  0.937  0.326  0.149  1.0
  Si  Si12  1  0.326  0.149  0.937  1.0
  Si  Si13  1  0.149  0.937  0.326  1.0
  Si  Si14  1  0.826  0.437  0.649  1.0
  Si  Si15  1  0.437  0.649  0.826  1.0
  Ir  Ir16  1  0.750  0.074  0.426  1.0
  Ir  Ir17  1  0.426  0.750  0.074  1.0
  Ir  Ir18  1  0.074  0.426  0.750  1.0
  Ir  Ir19  1  0.250  0.926  0.574  1.0
  Ir  Ir20  1  0.574  0.250  0.926  1.0
  Ir  Ir21  1  0.926  0.574  0.250  1.0
[/CIF]
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