The crystal structure described by Sr5Ca3Si4 crystallizes in the monoclinic Pm space group. There are five inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 5-coordinate geometry to one Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. In the second Sr site, Sr(2) is bonded in a 5-coordinate geometry to one Si(2), two equivalent Si(3), and two equivalent Si(4) atoms. In the third Sr site, Sr(3) is bonded in a 5-coordinate geometry to one Si(3), two equivalent Si(1), and two equivalent Si(2) atoms. In the fourth Sr site, Sr(4) is bonded in a 3-coordinate geometry to one Si(4), two equivalent Si(1), and two equivalent Si(2) atoms. In the fifth Sr site, Sr(5) is bonded to one Si(1), one Si(2), and two equivalent Si(4) atoms to form SrSi4 tetrahedra that share corners with two equivalent Sr(5)Si4 tetrahedra, corners with two equivalent Ca(1)Si4 tetrahedra, corners with four equivalent Ca(3)Si4 tetrahedra, and edges with two equivalent Ca(2)Si4 tetrahedra. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one Si(1), one Si(2), and two equivalent Si(3) atoms to form distorted CaSi4 tetrahedra that share corners with two equivalent Sr(5)Si4 tetrahedra, corners with two equivalent Ca(1)Si4 tetrahedra, corners with four equivalent Ca(2)Si4 tetrahedra, and edges with two equivalent Ca(3)Si4 tetrahedra. In the second Ca site, Ca(2) is bonded to one Si(3), one Si(4), and two equivalent Si(2) atoms to form distorted CaSi4 tetrahedra that share corners with two equivalent Ca(2)Si4 tetrahedra, corners with two equivalent Ca(3)Si4 tetrahedra, corners with four equivalent Ca(1)Si4 tetrahedra, and edges with two equivalent Sr(5)Si4 tetrahedra. In the third Ca site, Ca(3) is bonded to one Si(3), one Si(4), and two equivalent Si(1) atoms to form distorted CaSi4 tetrahedra that share corners with two equivalent Ca(2)Si4 tetrahedra, corners with two equivalent Ca(3)Si4 tetrahedra, corners with four equivalent Sr(5)Si4 tetrahedra, and edges with two equivalent Ca(1)Si4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Sr(1), one Sr(5), two equivalent Sr(3), two equivalent Sr(4), one Ca(1), and two equivalent Ca(3) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Sr(2), one Sr(5), two equivalent Sr(3), two equivalent Sr(4), one Ca(1), and two equivalent Ca(2) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Sr(3), two equivalent Sr(1), two equivalent Sr(2), one Ca(2), one Ca(3), and two equivalent Ca(1) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Sr(4), two equivalent Sr(1), two equivalent Sr(2), two equivalent Sr(5), one Ca(2), and one Ca(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr5Ca3Si4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.991
_cell_length_b   8.088
_cell_length_c   9.241
_cell_angle_alpha   90.463
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   372.996
_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  0.750  0.477  0.823  1.0
  Sr  Sr1  1  0.750  0.979  0.683  1.0
  Sr  Sr2  1  0.250  0.524  0.174  1.0
  Sr  Sr3  1  0.250  0.017  0.321  1.0
  Sr  Sr4  1  0.750  0.348  0.424  1.0
  Ca  Ca5  1  0.750  0.854  0.072  1.0
  Ca  Ca6  1  0.250  0.650  0.576  1.0
  Ca  Ca7  1  0.250  0.147  0.927  1.0
  Si  Si8  1  0.750  0.231  0.097  1.0
  Si  Si9  1  0.750  0.743  0.394  1.0
  Si  Si10  1  0.250  0.766  0.896  1.0
  Si  Si11  1  0.250  0.265  0.614  1.0
[/CIF]
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The crystal structure described by Sr5Ca3Si4 crystallizes in the monoclinic Pm space group. There are five inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 5-coordinate geometry to one Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. In the second Sr site, Sr(2) is bonded in a 5-coordinate geometry to one Si(2), two equivalent Si(3), and two equivalent Si(4) atoms. In the third Sr site, Sr(3) is bonded in a 5-coordinate geometry to one Si(3), two equivalent Si(1), and two equivalent Si(2) atoms. In the fourth Sr site, Sr(4) is bonded in a 3-coordinate geometry to one Si(4), two equivalent Si(1), and two equivalent Si(2) atoms. In the fifth Sr site, Sr(5) is bonded to one Si(1), one Si(2), and two equivalent Si(4) atoms to form SrSi4 tetrahedra that share corners with two equivalent Sr(5)Si4 tetrahedra, corners with two equivalent Ca(1)Si4 tetrahedra, corners with four equivalent Ca(3)Si4 tetrahedra, and edges with two equivalent Ca(2)Si4 tetrahedra. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one Si(1), one Si(2), and two equivalent Si(3) atoms to form distorted CaSi4 tetrahedra that share corners with two equivalent Sr(5)Si4 tetrahedra, corners with two equivalent Ca(1)Si4 tetrahedra, corners with four equivalent Ca(2)Si4 tetrahedra, and edges with two equivalent Ca(3)Si4 tetrahedra. In the second Ca site, Ca(2) is bonded to one Si(3), one Si(4), and two equivalent Si(2) atoms to form distorted CaSi4 tetrahedra that share corners with two equivalent Ca(2)Si4 tetrahedra, corners with two equivalent Ca(3)Si4 tetrahedra, corners with four equivalent Ca(1)Si4 tetrahedra, and edges with two equivalent Sr(5)Si4 tetrahedra. In the third Ca site, Ca(3) is bonded to one Si(3), one Si(4), and two equivalent Si(1) atoms to form distorted CaSi4 tetrahedra that share corners with two equivalent Ca(2)Si4 tetrahedra, corners with two equivalent Ca(3)Si4 tetrahedra, corners with four equivalent Sr(5)Si4 tetrahedra, and edges with two equivalent Ca(1)Si4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Sr(1), one Sr(5), two equivalent Sr(3), two equivalent Sr(4), one Ca(1), and two equivalent Ca(3) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Sr(2), one Sr(5), two equivalent Sr(3), two equivalent Sr(4), one Ca(1), and two equivalent Ca(2) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Sr(3), two equivalent Sr(1), two equivalent Sr(2), one Ca(2), one Ca(3), and two equivalent Ca(1) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Sr(4), two equivalent Sr(1), two equivalent Sr(2), two equivalent Sr(5), one Ca(2), and one Ca(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr5Ca3Si4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.991
_cell_length_b   8.088
_cell_length_c   9.241
_cell_angle_alpha   90.463
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   372.996
_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  0.750  0.477  0.823  1.0
  Sr  Sr1  1  0.750  0.979  0.683  1.0
  Sr  Sr2  1  0.250  0.524  0.174  1.0
  Sr  Sr3  1  0.250  0.017  0.321  1.0
  Sr  Sr4  1  0.750  0.348  0.424  1.0
  Ca  Ca5  1  0.750  0.854  0.072  1.0
  Ca  Ca6  1  0.250  0.650  0.576  1.0
  Ca  Ca7  1  0.250  0.147  0.927  1.0
  Si  Si8  1  0.750  0.231  0.097  1.0
  Si  Si9  1  0.750  0.743  0.394  1.0
  Si  Si10  1  0.250  0.766  0.896  1.0
  Si  Si11  1  0.250  0.265  0.614  1.0
[/CIF]
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