The crystal structure described by Sr2CaTi6N2O11 crystallizes in the monoclinic Cm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one O(4), one O(8), two equivalent O(10), two equivalent O(11), and two equivalent O(3) atoms. In the second Sr site, Sr(2) is bonded to two equivalent N(2), two equivalent O(1), and two equivalent O(9) atoms to form distorted SrN2O4 pentagonal pyramids that share corners with two equivalent Ti(2)NO5 octahedra, corners with two equivalent Ti(6)NO3 tetrahedra, corners with two equivalent Ti(1)NO4 trigonal bipyramids, edges with two equivalent Ti(4)N3O2 trigonal bipyramids, and faces with two equivalent Sr(2)N2O4 pentagonal pyramids. The corner-sharing octahedral tilt angles are 54°. Ca(1) is bonded in a 5-coordinate geometry to one N(2), one O(4), one O(6), and two equivalent O(3) atoms. There are six inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one N(1), one O(1), one O(11), and two equivalent O(4) atoms to form distorted TiNO4 trigonal bipyramids that share corners with two equivalent Sr(2)N2O4 pentagonal pyramids,  a cornercorner with one Ti(6)NO3 tetrahedra, corners with two equivalent Ti(4)N3O2 trigonal bipyramids, corners with two equivalent Ti(1)NO4 trigonal bipyramids, and  an edgeedge with one Ti(2)NO5 octahedra. In the second Ti site, Ti(2) is bonded to one N(1), one O(1), one O(2), one O(7), and two equivalent O(5) atoms to form distorted TiNO5 octahedra that share corners with two equivalent Ti(2)NO5 octahedra, corners with two equivalent Sr(2)N2O4 pentagonal pyramids,  an edgeedge with one Ti(1)NO4 trigonal bipyramid,  an edgeedge with one Ti(3)O5 trigonal bipyramid, and edges with two equivalent Ti(4)N3O2 trigonal bipyramids. The corner-sharing octahedral tilt angles are 35°. In the third Ti site, Ti(3) is bonded to one O(2), one O(3), one O(7), and two equivalent O(6) atoms to form distorted TiO5 trigonal bipyramids that share corners with two equivalent Ti(3)O5 trigonal bipyramids and  an edgeedge with one Ti(2)NO5 octahedra. In the fourth Ti site, Ti(4) is bonded to one N(2), two equivalent N(1), one O(5), and one O(9) atom to form TiN3O2 trigonal bipyramids that share  a cornercorner with one Ti(6)NO3 tetrahedra, corners with two equivalent Ti(4)N3O2 trigonal bipyramids, corners with two equivalent Ti(1)NO4 trigonal bipyramids, edges with two equivalent Ti(2)NO5 octahedra, and edges with two equivalent Sr(2)N2O4 pentagonal pyramids. In the fifth Ti site, Ti(5) is bonded in a 6-coordinate geometry to one O(10), one O(5), one O(6), one O(9), and two equivalent O(7) atoms. In the sixth Ti site, Ti(6) is bonded to one N(2), one O(11), and two equivalent O(8) atoms to form TiNO3 tetrahedra that share corners with two equivalent Sr(2)N2O4 pentagonal pyramids, corners with two equivalent Ti(6)NO3 tetrahedra,  a cornercorner with one Ti(4)N3O2 trigonal bipyramid, and  a cornercorner with one Ti(1)NO4 trigonal bipyramid. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Ti(1), one Ti(2), and two equivalent Ti(4) atoms to form NTi4 trigonal pyramids that share corners with two equivalent N(1)Ti4 trigonal pyramids,  an edgeedge with one O(1)Sr2Ti2 tetrahedra, and edges with two equivalent O(5)Ti4 trigonal pyramids. In the second N site, N(2) is bonded in a 5-coordinate geometry to two equivalent Sr(2), one Ca(1), one Ti(4), and one Ti(6) atom. There are eleven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(2), one Ti(1), and one Ti(2) atom to form distorted OSr2Ti2 tetrahedra that share corners with two equivalent O(1)Sr2Ti2 tetrahedra, corners with two equivalent O(5)Ti4 trigonal pyramids, and  an edgeedge with one N(1)Ti4 trigonal pyramid. In the second O site, O(2) is bonded in a water-like geometry to one Ti(2) and one Ti(3) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to two equivalent Sr(1), two equivalent Ca(1), and one Ti(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sr(1), one Ca(1), and two equivalent Ti(1) atoms. In the fifth O site, O(5) is bonded to one Ti(4), one Ti(5), and two equivalent Ti(2) atoms to form distorted OTi4 trigonal pyramids that share corners with two equivalent O(1)Sr2Ti2 tetrahedra, corners with two equivalent O(5)Ti4 trigonal pyramids, and edges with two equivalent N(1)Ti4 trigonal pyramids. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Ca(1), one Ti(5), and two equivalent Ti(3) atoms. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Ti(2), one Ti(3), and two equivalent Ti(5) atoms. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Sr(1) and two equivalent Ti(6) atoms. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sr(2), one Ti(4), and one Ti(5) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to two equivalent Sr(1) and one Ti(5) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Ti(1), and one Ti(6) atom. is represented by the CIF file [CIF]
data_Sr2CaTi6N2O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.637
_cell_length_b   8.495
_cell_length_c   10.085
_cell_angle_alpha   81.059
_cell_angle_beta   90.002
_cell_angle_gamma   77.635
_symmetry_Int_Tables_number   1
_cell_volume   300.498
_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  0.522  0.952  0.811  1.0
  Sr  Sr1  1  0.452  0.093  0.293  1.0
  Ca  Ca2  1  0.725  0.547  0.960  1.0
  Ti  Ti3  1  0.108  0.780  0.124  1.0
  Ti  Ti4  1  0.174  0.648  0.396  1.0
  Ti  Ti5  1  0.205  0.586  0.696  1.0
  Ti  Ti6  1  0.778  0.441  0.268  1.0
  Ti  Ti7  1  0.838  0.321  0.585  1.0
  Ti  Ti8  1  0.893  0.209  0.971  1.0
  N  N9  1  0.228  0.541  0.212  1.0
  N  N10  1  0.858  0.281  0.135  1.0
  O  O11  1  0.063  0.870  0.286  1.0
  O  O12  1  0.120  0.758  0.570  1.0
  O  O13  1  0.156  0.684  0.853  1.0
  O  O14  1  0.618  0.761  0.068  1.0
  O  O15  1  0.707  0.582  0.423  1.0
  O  O16  1  0.749  0.498  0.728  1.0
  O  O17  1  0.295  0.406  0.571  1.0
  O  O18  1  0.361  0.274  0.910  1.0
  O  O19  1  0.873  0.252  0.412  1.0
  O  O20  1  0.931  0.135  0.697  1.0
  O  O21  1  0.003  0.990  0.987  1.0
[/CIF]
.
The crystal structure described by Sr2CaTi6N2O11 crystallizes in the monoclinic Cm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one O(4), one O(8), two equivalent O(10), two equivalent O(11), and two equivalent O(3) atoms. In the second Sr site, Sr(2) is bonded to two equivalent N(2), two equivalent O(1), and two equivalent O(9) atoms to form distorted SrN2O4 pentagonal pyramids that share corners with two equivalent Ti(2)NO5 octahedra, corners with two equivalent Ti(6)NO3 tetrahedra, corners with two equivalent Ti(1)NO4 trigonal bipyramids, edges with two equivalent Ti(4)N3O2 trigonal bipyramids, and faces with two equivalent Sr(2)N2O4 pentagonal pyramids. The corner-sharing octahedral tilt angles are 54°. Ca(1) is bonded in a 5-coordinate geometry to one N(2), one O(4), one O(6), and two equivalent O(3) atoms. There are six inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one N(1), one O(1), one O(11), and two equivalent O(4) atoms to form distorted TiNO4 trigonal bipyramids that share corners with two equivalent Sr(2)N2O4 pentagonal pyramids,  a cornercorner with one Ti(6)NO3 tetrahedra, corners with two equivalent Ti(4)N3O2 trigonal bipyramids, corners with two equivalent Ti(1)NO4 trigonal bipyramids, and  an edgeedge with one Ti(2)NO5 octahedra. In the second Ti site, Ti(2) is bonded to one N(1), one O(1), one O(2), one O(7), and two equivalent O(5) atoms to form distorted TiNO5 octahedra that share corners with two equivalent Ti(2)NO5 octahedra, corners with two equivalent Sr(2)N2O4 pentagonal pyramids,  an edgeedge with one Ti(1)NO4 trigonal bipyramid,  an edgeedge with one Ti(3)O5 trigonal bipyramid, and edges with two equivalent Ti(4)N3O2 trigonal bipyramids. The corner-sharing octahedral tilt angles are 35°. In the third Ti site, Ti(3) is bonded to one O(2), one O(3), one O(7), and two equivalent O(6) atoms to form distorted TiO5 trigonal bipyramids that share corners with two equivalent Ti(3)O5 trigonal bipyramids and  an edgeedge with one Ti(2)NO5 octahedra. In the fourth Ti site, Ti(4) is bonded to one N(2), two equivalent N(1), one O(5), and one O(9) atom to form TiN3O2 trigonal bipyramids that share  a cornercorner with one Ti(6)NO3 tetrahedra, corners with two equivalent Ti(4)N3O2 trigonal bipyramids, corners with two equivalent Ti(1)NO4 trigonal bipyramids, edges with two equivalent Ti(2)NO5 octahedra, and edges with two equivalent Sr(2)N2O4 pentagonal pyramids. In the fifth Ti site, Ti(5) is bonded in a 6-coordinate geometry to one O(10), one O(5), one O(6), one O(9), and two equivalent O(7) atoms. In the sixth Ti site, Ti(6) is bonded to one N(2), one O(11), and two equivalent O(8) atoms to form TiNO3 tetrahedra that share corners with two equivalent Sr(2)N2O4 pentagonal pyramids, corners with two equivalent Ti(6)NO3 tetrahedra,  a cornercorner with one Ti(4)N3O2 trigonal bipyramid, and  a cornercorner with one Ti(1)NO4 trigonal bipyramid. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Ti(1), one Ti(2), and two equivalent Ti(4) atoms to form NTi4 trigonal pyramids that share corners with two equivalent N(1)Ti4 trigonal pyramids,  an edgeedge with one O(1)Sr2Ti2 tetrahedra, and edges with two equivalent O(5)Ti4 trigonal pyramids. In the second N site, N(2) is bonded in a 5-coordinate geometry to two equivalent Sr(2), one Ca(1), one Ti(4), and one Ti(6) atom. There are eleven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(2), one Ti(1), and one Ti(2) atom to form distorted OSr2Ti2 tetrahedra that share corners with two equivalent O(1)Sr2Ti2 tetrahedra, corners with two equivalent O(5)Ti4 trigonal pyramids, and  an edgeedge with one N(1)Ti4 trigonal pyramid. In the second O site, O(2) is bonded in a water-like geometry to one Ti(2) and one Ti(3) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to two equivalent Sr(1), two equivalent Ca(1), and one Ti(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sr(1), one Ca(1), and two equivalent Ti(1) atoms. In the fifth O site, O(5) is bonded to one Ti(4), one Ti(5), and two equivalent Ti(2) atoms to form distorted OTi4 trigonal pyramids that share corners with two equivalent O(1)Sr2Ti2 tetrahedra, corners with two equivalent O(5)Ti4 trigonal pyramids, and edges with two equivalent N(1)Ti4 trigonal pyramids. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Ca(1), one Ti(5), and two equivalent Ti(3) atoms. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Ti(2), one Ti(3), and two equivalent Ti(5) atoms. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Sr(1) and two equivalent Ti(6) atoms. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sr(2), one Ti(4), and one Ti(5) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to two equivalent Sr(1) and one Ti(5) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Ti(1), and one Ti(6) atom. is represented by the CIF file [CIF]
data_Sr2CaTi6N2O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.637
_cell_length_b   8.495
_cell_length_c   10.085
_cell_angle_alpha   81.059
_cell_angle_beta   90.002
_cell_angle_gamma   77.635
_symmetry_Int_Tables_number   1
_cell_volume   300.498
_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  0.522  0.952  0.811  1.0
  Sr  Sr1  1  0.452  0.093  0.293  1.0
  Ca  Ca2  1  0.725  0.547  0.960  1.0
  Ti  Ti3  1  0.108  0.780  0.124  1.0
  Ti  Ti4  1  0.174  0.648  0.396  1.0
  Ti  Ti5  1  0.205  0.586  0.696  1.0
  Ti  Ti6  1  0.778  0.441  0.268  1.0
  Ti  Ti7  1  0.838  0.321  0.585  1.0
  Ti  Ti8  1  0.893  0.209  0.971  1.0
  N  N9  1  0.228  0.541  0.212  1.0
  N  N10  1  0.858  0.281  0.135  1.0
  O  O11  1  0.063  0.870  0.286  1.0
  O  O12  1  0.120  0.758  0.570  1.0
  O  O13  1  0.156  0.684  0.853  1.0
  O  O14  1  0.618  0.761  0.068  1.0
  O  O15  1  0.707  0.582  0.423  1.0
  O  O16  1  0.749  0.498  0.728  1.0
  O  O17  1  0.295  0.406  0.571  1.0
  O  O18  1  0.361  0.274  0.910  1.0
  O  O19  1  0.873  0.252  0.412  1.0
  O  O20  1  0.931  0.135  0.697  1.0
  O  O21  1  0.003  0.990  0.987  1.0
[/CIF]
.