The compound described by SrAl4Si2N8O crystallizes in the orthorhombic Imm2 space group. Sr(1) is bonded in a water-like geometry to two equivalent N(2) atoms. Al(1) is bonded to one N(2), one N(3), and two equivalent N(1) atoms to form AlN4 tetrahedra that share corners with three equivalent Si(1)N3O tetrahedra and corners with four equivalent Al(1)N4 tetrahedra. Si(1) is bonded to one N(3), two equivalent N(1), and one O(1) atom to form SiN3O tetrahedra that share  a cornercorner with one Si(1)N3O tetrahedra and corners with six equivalent Al(1)N4 tetrahedra. There are three inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to two equivalent Al(1) and one Si(1) atom. In the second N site, N(2) is bonded in a distorted trigonal planar geometry to one Sr(1) and two equivalent Al(1) atoms. In the third N site, N(3) is bonded in a trigonal planar geometry to two equivalent Al(1) and one Si(1) atom. O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_SrAl4Si2N8O
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.141
_cell_length_b   7.141
_cell_length_c   7.141
_cell_angle_alpha   137.144
_cell_angle_beta   107.026
_cell_angle_gamma   88.518
_symmetry_Int_Tables_number   1
_cell_volume   226.597
_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  0.500  0.225  0.725  1.0
  Al  Al1  1  0.640  0.413  0.391  1.0
  Al  Al2  1  0.360  0.751  0.773  1.0
  Al  Al3  1  0.978  0.751  0.391  1.0
  Al  Al4  1  0.022  0.413  0.773  1.0
  Si  Si5  1  0.158  0.240  0.082  1.0
  Si  Si6  1  0.842  0.923  0.082  1.0
  N  N7  1  0.617  0.705  0.761  1.0
  N  N8  1  0.383  0.144  0.088  1.0
  N  N9  1  0.056  0.144  0.761  1.0
  N  N10  1  0.944  0.705  0.088  1.0
  N  N11  1  0.271  0.540  0.811  1.0
  N  N12  1  0.729  0.540  0.268  1.0
  N  N13  1  0.189  0.596  0.407  1.0
  N  N14  1  0.811  0.217  0.407  1.0
  O  O15  1  0.000  0.027  0.027  1.0
[/CIF]
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The compound described by SrAl4Si2N8O crystallizes in the orthorhombic Imm2 space group. Sr(1) is bonded in a water-like geometry to two equivalent N(2) atoms. Al(1) is bonded to one N(2), one N(3), and two equivalent N(1) atoms to form AlN4 tetrahedra that share corners with three equivalent Si(1)N3O tetrahedra and corners with four equivalent Al(1)N4 tetrahedra. Si(1) is bonded to one N(3), two equivalent N(1), and one O(1) atom to form SiN3O tetrahedra that share  a cornercorner with one Si(1)N3O tetrahedra and corners with six equivalent Al(1)N4 tetrahedra. There are three inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to two equivalent Al(1) and one Si(1) atom. In the second N site, N(2) is bonded in a distorted trigonal planar geometry to one Sr(1) and two equivalent Al(1) atoms. In the third N site, N(3) is bonded in a trigonal planar geometry to two equivalent Al(1) and one Si(1) atom. O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_SrAl4Si2N8O
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.141
_cell_length_b   7.141
_cell_length_c   7.141
_cell_angle_alpha   137.144
_cell_angle_beta   107.026
_cell_angle_gamma   88.518
_symmetry_Int_Tables_number   1
_cell_volume   226.597
_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  0.500  0.225  0.725  1.0
  Al  Al1  1  0.640  0.413  0.391  1.0
  Al  Al2  1  0.360  0.751  0.773  1.0
  Al  Al3  1  0.978  0.751  0.391  1.0
  Al  Al4  1  0.022  0.413  0.773  1.0
  Si  Si5  1  0.158  0.240  0.082  1.0
  Si  Si6  1  0.842  0.923  0.082  1.0
  N  N7  1  0.617  0.705  0.761  1.0
  N  N8  1  0.383  0.144  0.088  1.0
  N  N9  1  0.056  0.144  0.761  1.0
  N  N10  1  0.944  0.705  0.088  1.0
  N  N11  1  0.271  0.540  0.811  1.0
  N  N12  1  0.729  0.540  0.268  1.0
  N  N13  1  0.189  0.596  0.407  1.0
  N  N14  1  0.811  0.217  0.407  1.0
  O  O15  1  0.000  0.027  0.027  1.0
[/CIF]
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