The material described by Sr9CaSi6 crystallizes in the tetragonal I4/m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 5-coordinate geometry to two equivalent Si(1) and three equivalent Si(2) atoms. In the second Sr site, Sr(2) is bonded in a square co-planar geometry to four equivalent Si(2) atoms. Ca(1) is bonded in a square co-planar geometry to four equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to eight equivalent Sr(1) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Sr(2), six equivalent Sr(1), one Ca(1), and one Si(2) atom. is represented by the CIF card [CIF]
data_Sr9CaSi6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.749
_cell_length_b   9.749
_cell_length_c   9.749
_cell_angle_alpha   131.412
_cell_angle_beta   131.412
_cell_angle_gamma   71.159
_symmetry_Int_Tables_number   1
_cell_volume   510.272
_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
  Sr  Sr0  1  0.539  0.043  0.861  1.0
  Sr  Sr1  1  0.182  0.678  0.139  1.0
  Sr  Sr2  1  0.043  0.182  0.504  1.0
  Sr  Sr3  1  0.678  0.539  0.496  1.0
  Sr  Sr4  1  0.461  0.957  0.139  1.0
  Sr  Sr5  1  0.818  0.322  0.861  1.0
  Sr  Sr6  1  0.957  0.818  0.496  1.0
  Sr  Sr7  1  0.322  0.461  0.504  1.0
  Sr  Sr8  1  0.000  0.000  0.000  1.0
  Ca  Ca9  1  0.500  0.500  0.000  1.0
  Si  Si10  1  0.250  0.250  0.000  1.0
  Si  Si11  1  0.750  0.750  0.000  1.0
  Si  Si12  1  0.888  0.394  0.282  1.0
  Si  Si13  1  0.112  0.606  0.718  1.0
  Si  Si14  1  0.394  0.112  0.507  1.0
  Si  Si15  1  0.606  0.888  0.493  1.0
[/CIF]
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The material described by Sr9CaSi6 crystallizes in the tetragonal I4/m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 5-coordinate geometry to two equivalent Si(1) and three equivalent Si(2) atoms. In the second Sr site, Sr(2) is bonded in a square co-planar geometry to four equivalent Si(2) atoms. Ca(1) is bonded in a square co-planar geometry to four equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to eight equivalent Sr(1) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Sr(2), six equivalent Sr(1), one Ca(1), and one Si(2) atom. is represented by the CIF card [CIF]
data_Sr9CaSi6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.749
_cell_length_b   9.749
_cell_length_c   9.749
_cell_angle_alpha   131.412
_cell_angle_beta   131.412
_cell_angle_gamma   71.159
_symmetry_Int_Tables_number   1
_cell_volume   510.272
_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
  Sr  Sr0  1  0.539  0.043  0.861  1.0
  Sr  Sr1  1  0.182  0.678  0.139  1.0
  Sr  Sr2  1  0.043  0.182  0.504  1.0
  Sr  Sr3  1  0.678  0.539  0.496  1.0
  Sr  Sr4  1  0.461  0.957  0.139  1.0
  Sr  Sr5  1  0.818  0.322  0.861  1.0
  Sr  Sr6  1  0.957  0.818  0.496  1.0
  Sr  Sr7  1  0.322  0.461  0.504  1.0
  Sr  Sr8  1  0.000  0.000  0.000  1.0
  Ca  Ca9  1  0.500  0.500  0.000  1.0
  Si  Si10  1  0.250  0.250  0.000  1.0
  Si  Si11  1  0.750  0.750  0.000  1.0
  Si  Si12  1  0.888  0.394  0.282  1.0
  Si  Si13  1  0.112  0.606  0.718  1.0
  Si  Si14  1  0.394  0.112  0.507  1.0
  Si  Si15  1  0.606  0.888  0.493  1.0
[/CIF]
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