The compound described by BaAlSi5O2N7 crystallizes in the triclinic P1 space group. Ba(1) is bonded in a 2-coordinate geometry to one N(7) and one O(2) atom. Al(1) is bonded to one N(1), one N(2), one N(5), and one O(2) atom to form AlN3O tetrahedra that share  a cornercorner with one Si(2)N3O tetrahedra,  a cornercorner with one Si(5)N3O tetrahedra,  a cornercorner with one Si(4)N4 tetrahedra, corners with two equivalent Si(1)N3O tetrahedra, and corners with two equivalent Si(3)N4 tetrahedra. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(1), one N(3), one N(5), and one O(1) atom to form SiN3O tetrahedra that share  a cornercorner with one Si(2)N3O tetrahedra,  a cornercorner with one Si(5)N3O tetrahedra,  a cornercorner with one Si(3)N4 tetrahedra, corners with two equivalent Al(1)N3O tetrahedra, and corners with two equivalent Si(4)N4 tetrahedra. In the second Si site, Si(2) is bonded to one N(2), one N(4), one N(6), and one O(1) atom to form SiN3O tetrahedra that share  a cornercorner with one Al(1)N3O tetrahedra,  a cornercorner with one Si(1)N3O tetrahedra,  a cornercorner with one Si(4)N4 tetrahedra, corners with two equivalent Si(5)N3O tetrahedra, and corners with two equivalent Si(3)N4 tetrahedra. In the third Si site, Si(3) is bonded to one N(1), one N(2), one N(6), and one N(7) atom to form SiN4 tetrahedra that share  a cornercorner with one Si(1)N3O tetrahedra,  a cornercorner with one Si(5)N3O tetrahedra,  a cornercorner with one Si(4)N4 tetrahedra, corners with two equivalent Al(1)N3O tetrahedra, and corners with two equivalent Si(2)N3O tetrahedra. In the fourth Si site, Si(4) is bonded to one N(3), one N(4), one N(5), and one N(7) atom to form SiN4 tetrahedra that share  a cornercorner with one Al(1)N3O tetrahedra,  a cornercorner with one Si(2)N3O tetrahedra,  a cornercorner with one Si(3)N4 tetrahedra, corners with two equivalent Si(1)N3O tetrahedra, and corners with two equivalent Si(5)N3O tetrahedra. In the fifth Si site, Si(5) is bonded to one N(3), one N(4), one N(6), and one O(2) atom to form SiN3O tetrahedra that share  a cornercorner with one Al(1)N3O tetrahedra,  a cornercorner with one Si(1)N3O tetrahedra,  a cornercorner with one Si(3)N4 tetrahedra, corners with two equivalent Si(2)N3O tetrahedra, and corners with two equivalent Si(4)N4 tetrahedra. There are seven inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one Al(1), one Si(1), and one Si(3) atom. In the second N site, N(2) is bonded in a trigonal planar geometry to one Al(1), one Si(2), and one Si(3) atom. In the third N site, N(3) is bonded in a trigonal planar geometry to one Si(1), one Si(4), and one Si(5) atom. In the fourth N site, N(4) is bonded in a trigonal planar geometry to one Si(2), one Si(4), and one Si(5) atom. In the fifth N site, N(5) is bonded in a distorted trigonal planar geometry to one Al(1), one Si(1), and one Si(4) atom. In the sixth N site, N(6) is bonded in a distorted trigonal planar geometry to one Si(2), one Si(3), and one Si(5) atom. In the seventh N site, N(7) is bonded in a 2-coordinate geometry to one Ba(1), one Si(3), and one Si(4) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(1), one Al(1), and one Si(5) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaAlSi5N7O2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.932
_cell_length_b   6.823
_cell_length_c   6.882
_cell_angle_alpha   74.479
_cell_angle_beta   69.540
_cell_angle_gamma   69.083
_symmetry_Int_Tables_number   1
_cell_volume   199.993
_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
  Ba  Ba0  1  0.200  0.011  0.994  1.0
  Al  Al1  1  0.822  0.531  0.147  1.0
  Si  Si2  1  0.321  0.335  0.334  1.0
  Si  Si3  1  0.991  0.658  0.658  1.0
  Si  Si4  1  0.503  0.464  0.855  1.0
  Si  Si5  1  0.814  0.144  0.536  1.0
  Si  Si6  1  0.488  0.859  0.476  1.0
  N  N7  1  0.238  0.450  0.099  1.0
  N  N8  1  0.768  0.559  0.888  1.0
  N  N9  1  0.214  0.102  0.449  1.0
  N  N10  1  0.772  0.895  0.547  1.0
  N  N11  1  0.687  0.302  0.320  1.0
  N  N12  1  0.314  0.686  0.684  1.0
  N  N13  1  0.634  0.224  0.774  1.0
  O  O14  1  0.071  0.500  0.492  1.0
  O  O15  1  0.620  0.778  0.246  1.0
[/CIF]
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The compound described by BaAlSi5O2N7 crystallizes in the triclinic P1 space group. Ba(1) is bonded in a 2-coordinate geometry to one N(7) and one O(2) atom. Al(1) is bonded to one N(1), one N(2), one N(5), and one O(2) atom to form AlN3O tetrahedra that share  a cornercorner with one Si(2)N3O tetrahedra,  a cornercorner with one Si(5)N3O tetrahedra,  a cornercorner with one Si(4)N4 tetrahedra, corners with two equivalent Si(1)N3O tetrahedra, and corners with two equivalent Si(3)N4 tetrahedra. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(1), one N(3), one N(5), and one O(1) atom to form SiN3O tetrahedra that share  a cornercorner with one Si(2)N3O tetrahedra,  a cornercorner with one Si(5)N3O tetrahedra,  a cornercorner with one Si(3)N4 tetrahedra, corners with two equivalent Al(1)N3O tetrahedra, and corners with two equivalent Si(4)N4 tetrahedra. In the second Si site, Si(2) is bonded to one N(2), one N(4), one N(6), and one O(1) atom to form SiN3O tetrahedra that share  a cornercorner with one Al(1)N3O tetrahedra,  a cornercorner with one Si(1)N3O tetrahedra,  a cornercorner with one Si(4)N4 tetrahedra, corners with two equivalent Si(5)N3O tetrahedra, and corners with two equivalent Si(3)N4 tetrahedra. In the third Si site, Si(3) is bonded to one N(1), one N(2), one N(6), and one N(7) atom to form SiN4 tetrahedra that share  a cornercorner with one Si(1)N3O tetrahedra,  a cornercorner with one Si(5)N3O tetrahedra,  a cornercorner with one Si(4)N4 tetrahedra, corners with two equivalent Al(1)N3O tetrahedra, and corners with two equivalent Si(2)N3O tetrahedra. In the fourth Si site, Si(4) is bonded to one N(3), one N(4), one N(5), and one N(7) atom to form SiN4 tetrahedra that share  a cornercorner with one Al(1)N3O tetrahedra,  a cornercorner with one Si(2)N3O tetrahedra,  a cornercorner with one Si(3)N4 tetrahedra, corners with two equivalent Si(1)N3O tetrahedra, and corners with two equivalent Si(5)N3O tetrahedra. In the fifth Si site, Si(5) is bonded to one N(3), one N(4), one N(6), and one O(2) atom to form SiN3O tetrahedra that share  a cornercorner with one Al(1)N3O tetrahedra,  a cornercorner with one Si(1)N3O tetrahedra,  a cornercorner with one Si(3)N4 tetrahedra, corners with two equivalent Si(2)N3O tetrahedra, and corners with two equivalent Si(4)N4 tetrahedra. There are seven inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one Al(1), one Si(1), and one Si(3) atom. In the second N site, N(2) is bonded in a trigonal planar geometry to one Al(1), one Si(2), and one Si(3) atom. In the third N site, N(3) is bonded in a trigonal planar geometry to one Si(1), one Si(4), and one Si(5) atom. In the fourth N site, N(4) is bonded in a trigonal planar geometry to one Si(2), one Si(4), and one Si(5) atom. In the fifth N site, N(5) is bonded in a distorted trigonal planar geometry to one Al(1), one Si(1), and one Si(4) atom. In the sixth N site, N(6) is bonded in a distorted trigonal planar geometry to one Si(2), one Si(3), and one Si(5) atom. In the seventh N site, N(7) is bonded in a 2-coordinate geometry to one Ba(1), one Si(3), and one Si(4) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(1), one Al(1), and one Si(5) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaAlSi5N7O2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.932
_cell_length_b   6.823
_cell_length_c   6.882
_cell_angle_alpha   74.479
_cell_angle_beta   69.540
_cell_angle_gamma   69.083
_symmetry_Int_Tables_number   1
_cell_volume   199.993
_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
  Ba  Ba0  1  0.200  0.011  0.994  1.0
  Al  Al1  1  0.822  0.531  0.147  1.0
  Si  Si2  1  0.321  0.335  0.334  1.0
  Si  Si3  1  0.991  0.658  0.658  1.0
  Si  Si4  1  0.503  0.464  0.855  1.0
  Si  Si5  1  0.814  0.144  0.536  1.0
  Si  Si6  1  0.488  0.859  0.476  1.0
  N  N7  1  0.238  0.450  0.099  1.0
  N  N8  1  0.768  0.559  0.888  1.0
  N  N9  1  0.214  0.102  0.449  1.0
  N  N10  1  0.772  0.895  0.547  1.0
  N  N11  1  0.687  0.302  0.320  1.0
  N  N12  1  0.314  0.686  0.684  1.0
  N  N13  1  0.634  0.224  0.774  1.0
  O  O14  1  0.071  0.500  0.492  1.0
  O  O15  1  0.620  0.778  0.246  1.0
[/CIF]
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