The crystal structure described by Sr3(SiAs2)2 crystallizes in the monoclinic C2/c space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to two equivalent As(1) and four equivalent As(2) atoms to form SrAs6 octahedra that share corners with two equivalent Sr(2)As6 octahedra, corners with two equivalent Sr(3)As6 octahedra, corners with four equivalent Si(1)SiAs3 tetrahedra, edges with two equivalent Sr(1)As6 octahedra, edges with three equivalent Sr(3)As6 octahedra, edges with four equivalent Sr(2)As6 octahedra, and edges with two equivalent Si(1)SiAs3 tetrahedra. The corner-sharing octahedral tilt angles range from 4-12°. In the second Sr site, Sr(2) is bonded to two equivalent As(1) and four equivalent As(2) atoms to form SrAs6 octahedra that share corners with two equivalent Sr(1)As6 octahedra, corners with two equivalent Sr(3)As6 octahedra, corners with eight equivalent Si(1)SiAs3 tetrahedra, edges with two equivalent Sr(2)As6 octahedra, edges with three equivalent Sr(3)As6 octahedra, and edges with four equivalent Sr(1)As6 octahedra. The corner-sharing octahedral tilt angles are 4°. In the third Sr site, Sr(3) is bonded to two equivalent As(2) and four equivalent As(1) atoms to form SrAs6 octahedra that share corners with two equivalent Sr(1)As6 octahedra, corners with two equivalent Sr(2)As6 octahedra, corners with six equivalent Si(1)SiAs3 tetrahedra, edges with two equivalent Sr(3)As6 octahedra, edges with three equivalent Sr(1)As6 octahedra, edges with three equivalent Sr(2)As6 octahedra, and edges with two equivalent Si(1)SiAs3 tetrahedra. The corner-sharing octahedral tilt angles range from 4-12°. Si(1) is bonded to one Si(1), one As(2), and two equivalent As(1) atoms to form distorted SiSiAs3 tetrahedra that share  a cornercorner with one As(2)Sr5Si octahedra, corners with two equivalent Sr(1)As6 octahedra, corners with two equivalent As(1)Sr4Si2 octahedra, corners with three equivalent Sr(3)As6 octahedra, corners with four equivalent Sr(2)As6 octahedra,  an edgeedge with one Sr(1)As6 octahedra,  an edgeedge with one Sr(3)As6 octahedra, and  an edgeedge with one Si(1)SiAs3 tetrahedra. The corner-sharing octahedral tilt angles range from 19-82°. There are two inequivalent As sites. In the first As site, As(1) is bonded to one Sr(1), one Sr(2), two equivalent Sr(3), and two equivalent Si(1) atoms to form distorted AsSr4Si2 octahedra that share corners with four equivalent As(1)Sr4Si2 octahedra, corners with four equivalent As(2)Sr5Si octahedra, corners with two equivalent Si(1)SiAs3 tetrahedra, edges with three equivalent As(1)Sr4Si2 octahedra, and edges with five equivalent As(2)Sr5Si octahedra. The corner-sharing octahedral tilt angles range from 4-95°. In the second As site, As(2) is bonded to one Sr(3), two equivalent Sr(1), two equivalent Sr(2), and one Si(1) atom to form AsSr5Si octahedra that share corners with three equivalent As(2)Sr5Si octahedra, corners with four equivalent As(1)Sr4Si2 octahedra,  a cornercorner with one Si(1)SiAs3 tetrahedra, edges with five equivalent As(1)Sr4Si2 octahedra, and edges with five equivalent As(2)Sr5Si octahedra. The corner-sharing octahedral tilt angles range from 1-90°. is represented by the CIF file [CIF]
data_Sr3(SiAs2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.413
_cell_length_b   8.181
_cell_length_c   9.634
_cell_angle_alpha   108.000
_cell_angle_beta   104.901
_cell_angle_gamma   107.460
_symmetry_Int_Tables_number   1
_cell_volume   489.038
_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
  Sr  Sr0  1  0.692  0.942  0.883  1.0
  Sr  Sr1  1  0.308  0.058  0.117  1.0
  Sr  Sr2  1  0.815  0.565  0.131  1.0
  Sr  Sr3  1  0.185  0.435  0.869  1.0
  Sr  Sr4  1  0.064  0.814  0.627  1.0
  Sr  Sr5  1  0.936  0.186  0.373  1.0
  Si  Si6  1  0.628  0.472  0.642  1.0
  Si  Si7  1  0.514  0.170  0.642  1.0
  Si  Si8  1  0.372  0.528  0.358  1.0
  Si  Si9  1  0.486  0.830  0.358  1.0
  As  As10  1  0.661  0.444  0.394  1.0
  As  As11  1  0.234  0.951  0.395  1.0
  As  As12  1  0.441  0.188  0.866  1.0
  As  As13  1  0.925  0.678  0.866  1.0
  As  As14  1  0.559  0.812  0.134  1.0
  As  As15  1  0.075  0.322  0.134  1.0
  As  As16  1  0.766  0.049  0.605  1.0
  As  As17  1  0.339  0.556  0.606  1.0
[/CIF]
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The crystal structure described by Sr3(SiAs2)2 crystallizes in the monoclinic C2/c space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to two equivalent As(1) and four equivalent As(2) atoms to form SrAs6 octahedra that share corners with two equivalent Sr(2)As6 octahedra, corners with two equivalent Sr(3)As6 octahedra, corners with four equivalent Si(1)SiAs3 tetrahedra, edges with two equivalent Sr(1)As6 octahedra, edges with three equivalent Sr(3)As6 octahedra, edges with four equivalent Sr(2)As6 octahedra, and edges with two equivalent Si(1)SiAs3 tetrahedra. The corner-sharing octahedral tilt angles range from 4-12°. In the second Sr site, Sr(2) is bonded to two equivalent As(1) and four equivalent As(2) atoms to form SrAs6 octahedra that share corners with two equivalent Sr(1)As6 octahedra, corners with two equivalent Sr(3)As6 octahedra, corners with eight equivalent Si(1)SiAs3 tetrahedra, edges with two equivalent Sr(2)As6 octahedra, edges with three equivalent Sr(3)As6 octahedra, and edges with four equivalent Sr(1)As6 octahedra. The corner-sharing octahedral tilt angles are 4°. In the third Sr site, Sr(3) is bonded to two equivalent As(2) and four equivalent As(1) atoms to form SrAs6 octahedra that share corners with two equivalent Sr(1)As6 octahedra, corners with two equivalent Sr(2)As6 octahedra, corners with six equivalent Si(1)SiAs3 tetrahedra, edges with two equivalent Sr(3)As6 octahedra, edges with three equivalent Sr(1)As6 octahedra, edges with three equivalent Sr(2)As6 octahedra, and edges with two equivalent Si(1)SiAs3 tetrahedra. The corner-sharing octahedral tilt angles range from 4-12°. Si(1) is bonded to one Si(1), one As(2), and two equivalent As(1) atoms to form distorted SiSiAs3 tetrahedra that share  a cornercorner with one As(2)Sr5Si octahedra, corners with two equivalent Sr(1)As6 octahedra, corners with two equivalent As(1)Sr4Si2 octahedra, corners with three equivalent Sr(3)As6 octahedra, corners with four equivalent Sr(2)As6 octahedra,  an edgeedge with one Sr(1)As6 octahedra,  an edgeedge with one Sr(3)As6 octahedra, and  an edgeedge with one Si(1)SiAs3 tetrahedra. The corner-sharing octahedral tilt angles range from 19-82°. There are two inequivalent As sites. In the first As site, As(1) is bonded to one Sr(1), one Sr(2), two equivalent Sr(3), and two equivalent Si(1) atoms to form distorted AsSr4Si2 octahedra that share corners with four equivalent As(1)Sr4Si2 octahedra, corners with four equivalent As(2)Sr5Si octahedra, corners with two equivalent Si(1)SiAs3 tetrahedra, edges with three equivalent As(1)Sr4Si2 octahedra, and edges with five equivalent As(2)Sr5Si octahedra. The corner-sharing octahedral tilt angles range from 4-95°. In the second As site, As(2) is bonded to one Sr(3), two equivalent Sr(1), two equivalent Sr(2), and one Si(1) atom to form AsSr5Si octahedra that share corners with three equivalent As(2)Sr5Si octahedra, corners with four equivalent As(1)Sr4Si2 octahedra,  a cornercorner with one Si(1)SiAs3 tetrahedra, edges with five equivalent As(1)Sr4Si2 octahedra, and edges with five equivalent As(2)Sr5Si octahedra. The corner-sharing octahedral tilt angles range from 1-90°. is represented by the CIF file [CIF]
data_Sr3(SiAs2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.413
_cell_length_b   8.181
_cell_length_c   9.634
_cell_angle_alpha   108.000
_cell_angle_beta   104.901
_cell_angle_gamma   107.460
_symmetry_Int_Tables_number   1
_cell_volume   489.038
_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
  Sr  Sr0  1  0.692  0.942  0.883  1.0
  Sr  Sr1  1  0.308  0.058  0.117  1.0
  Sr  Sr2  1  0.815  0.565  0.131  1.0
  Sr  Sr3  1  0.185  0.435  0.869  1.0
  Sr  Sr4  1  0.064  0.814  0.627  1.0
  Sr  Sr5  1  0.936  0.186  0.373  1.0
  Si  Si6  1  0.628  0.472  0.642  1.0
  Si  Si7  1  0.514  0.170  0.642  1.0
  Si  Si8  1  0.372  0.528  0.358  1.0
  Si  Si9  1  0.486  0.830  0.358  1.0
  As  As10  1  0.661  0.444  0.394  1.0
  As  As11  1  0.234  0.951  0.395  1.0
  As  As12  1  0.441  0.188  0.866  1.0
  As  As13  1  0.925  0.678  0.866  1.0
  As  As14  1  0.559  0.812  0.134  1.0
  As  As15  1  0.075  0.322  0.134  1.0
  As  As16  1  0.766  0.049  0.605  1.0
  As  As17  1  0.339  0.556  0.606  1.0
[/CIF]
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