The structure described by Sr6Mg(W2O9)2 crystallizes in the triclinic P1 space group. There are six inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(18), one O(2), one O(3), and one O(5) atom. In the second Sr site, Sr(2) is bonded to one O(10), one O(14), one O(2), one O(4), one O(6), and one O(7) atom to form distorted SrO6 pentagonal pyramids that share corners with two equivalent W(2)O6 octahedra, corners with two equivalent W(4)O6 octahedra,  an edgeedge with one W(1)O6 octahedra, and  an edgeedge with one W(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-66°. In the third Sr site, Sr(3) is bonded in a 5-coordinate geometry to one O(1), one O(13), one O(14), one O(3), one O(8), and one O(9) atom. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one O(10), one O(13), one O(14), one O(16), one O(17), one O(18), and one O(7) atom. In the fifth Sr site, Sr(5) is bonded in a 6-coordinate geometry to one O(12), one O(15), one O(2), one O(4), one O(6), and one O(9) atom. In the sixth Sr site, Sr(6) is bonded to one O(11), one O(12), one O(16), one O(17), one O(8), and one O(9) atom to form distorted SrO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with two equivalent W(3)O6 octahedra,  an edgeedge with one W(2)O6 octahedra, and  an edgeedge with one W(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-71°. Mg(1) is bonded in a rectangular see-saw-like geometry to one O(11), one O(13), one O(15), and one O(17) atom. There are four inequivalent W sites. In the first W site, W(1) is bonded to one O(12), one O(14), one O(18), one O(2), one O(3), and one O(9) atom to form distorted WO6 octahedra that share corners with two equivalent Sr(6)O6 octahedra,  an edgeedge with one Sr(2)O6 pentagonal pyramid, and  a faceface with one W(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-71°. In the second W site, W(2) is bonded to one O(11), one O(13), one O(16), one O(4), one O(5), and one O(6) atom to form distorted WO6 octahedra that share corners with two equivalent Sr(2)O6 pentagonal pyramids,  an edgeedge with one Sr(6)O6 octahedra, and  a faceface with one W(3)O6 octahedra. In the third W site, W(3) is bonded to one O(1), one O(10), one O(16), one O(17), one O(5), and one O(6) atom to form distorted WO6 octahedra that share corners with two equivalent Sr(6)O6 octahedra,  an edgeedge with one Sr(2)O6 pentagonal pyramid, and  a faceface with one W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-59°. In the fourth W site, W(4) is bonded to one O(12), one O(14), one O(15), one O(3), one O(7), and one O(8) atom to form distorted WO6 octahedra that share corners with two equivalent Sr(2)O6 pentagonal pyramids,  an edgeedge with one Sr(6)O6 octahedra, and  a faceface with one W(1)O6 octahedra. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Sr(1), one Sr(3), and one W(3) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Sr(1), one Sr(2), one Sr(5), and one W(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one W(1), and one W(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Sr(2), one Sr(5), and one W(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Sr(1), one W(2), and one W(3) atom. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Sr(2), one Sr(5), one W(2), and one W(3) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(4), and one W(4) atom. In the eighth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Sr(3), one Sr(6), and one W(4) atom. In the ninth O site, O(9) is bonded to one Sr(3), one Sr(5), one Sr(6), and one W(1) atom to form distorted corner-sharing OSr3W tetrahedra. In the tenth O site, O(10) is bonded to one Sr(1), one Sr(2), one Sr(4), and one W(3) atom to form corner-sharing OSr3W tetrahedra. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Sr(6), one Mg(1), and one W(2) atom. In the twelfth O site, O(12) is bonded in a rectangular see-saw-like geometry to one Sr(5), one Sr(6), one W(1), and one W(4) atom. In the thirteenth O site, O(13) is bonded to one Sr(3), one Sr(4), one Mg(1), and one W(2) atom to form distorted corner-sharing OSr2MgW tetrahedra. In the fourteenth O site, O(14) is bonded in a 5-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), one W(1), and one W(4) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Sr(5), one Mg(1), and one W(4) atom. In the sixteenth O site, O(16) is bonded in a rectangular see-saw-like geometry to one Sr(4), one Sr(6), one W(2), and one W(3) atom. In the seventeenth O site, O(17) is bonded in a distorted rectangular see-saw-like geometry to one Sr(4), one Sr(6), one Mg(1), and one W(3) atom. In the eighteenth O site, O(18) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(4), and one W(1) atom. is represented by the CIF card [CIF]
data_Sr6Mg(W2O9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.495
_cell_length_b   8.896
_cell_length_c   7.252
_cell_angle_alpha   79.973
_cell_angle_beta   81.274
_cell_angle_gamma   77.876
_symmetry_Int_Tables_number   1
_cell_volume   462.230
_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  0.220  0.009  0.733  1.0
  Sr  Sr1  1  0.157  0.480  0.787  1.0
  Sr  Sr2  1  0.470  0.710  0.132  1.0
  Sr  Sr3  1  0.721  0.284  0.937  1.0
  Sr  Sr4  1  0.989  0.650  0.258  1.0
  Sr  Sr5  1  0.654  0.998  0.360  1.0
  Mg  Mg6  1  0.736  0.327  0.392  1.0
  W  W7  1  0.830  0.836  0.823  1.0
  W  W8  1  0.348  0.339  0.330  1.0
  W  W9  1  0.148  0.154  0.160  1.0
  W  W10  1  0.639  0.642  0.650  1.0
  O  O11  1  0.211  0.943  0.135  1.0
  O  O12  1  0.076  0.761  0.861  1.0
  O  O13  1  0.556  0.838  0.786  1.0
  O  O14  1  0.237  0.522  0.433  1.0
  O  O15  1  0.185  0.173  0.429  1.0
  O  O16  1  0.138  0.402  0.148  1.0
  O  O17  1  0.477  0.527  0.788  1.0
  O  O18  1  0.513  0.757  0.454  1.0
  O  O19  1  0.745  0.838  0.083  1.0
  O  O20  1  0.088  0.223  0.893  1.0
  O  O21  1  0.522  0.227  0.512  1.0
  O  O22  1  0.852  0.783  0.557  1.0
  O  O23  1  0.567  0.434  0.202  1.0
  O  O24  1  0.801  0.593  0.861  1.0
  O  O25  1  0.793  0.489  0.515  1.0
  O  O26  1  0.433  0.179  0.139  1.0
  O  O27  1  0.876  0.173  0.234  1.0
  O  O28  1  0.841  0.041  0.747  1.0
[/CIF]
.
The structure described by Sr6Mg(W2O9)2 crystallizes in the triclinic P1 space group. There are six inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(18), one O(2), one O(3), and one O(5) atom. In the second Sr site, Sr(2) is bonded to one O(10), one O(14), one O(2), one O(4), one O(6), and one O(7) atom to form distorted SrO6 pentagonal pyramids that share corners with two equivalent W(2)O6 octahedra, corners with two equivalent W(4)O6 octahedra,  an edgeedge with one W(1)O6 octahedra, and  an edgeedge with one W(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-66°. In the third Sr site, Sr(3) is bonded in a 5-coordinate geometry to one O(1), one O(13), one O(14), one O(3), one O(8), and one O(9) atom. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one O(10), one O(13), one O(14), one O(16), one O(17), one O(18), and one O(7) atom. In the fifth Sr site, Sr(5) is bonded in a 6-coordinate geometry to one O(12), one O(15), one O(2), one O(4), one O(6), and one O(9) atom. In the sixth Sr site, Sr(6) is bonded to one O(11), one O(12), one O(16), one O(17), one O(8), and one O(9) atom to form distorted SrO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with two equivalent W(3)O6 octahedra,  an edgeedge with one W(2)O6 octahedra, and  an edgeedge with one W(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-71°. Mg(1) is bonded in a rectangular see-saw-like geometry to one O(11), one O(13), one O(15), and one O(17) atom. There are four inequivalent W sites. In the first W site, W(1) is bonded to one O(12), one O(14), one O(18), one O(2), one O(3), and one O(9) atom to form distorted WO6 octahedra that share corners with two equivalent Sr(6)O6 octahedra,  an edgeedge with one Sr(2)O6 pentagonal pyramid, and  a faceface with one W(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-71°. In the second W site, W(2) is bonded to one O(11), one O(13), one O(16), one O(4), one O(5), and one O(6) atom to form distorted WO6 octahedra that share corners with two equivalent Sr(2)O6 pentagonal pyramids,  an edgeedge with one Sr(6)O6 octahedra, and  a faceface with one W(3)O6 octahedra. In the third W site, W(3) is bonded to one O(1), one O(10), one O(16), one O(17), one O(5), and one O(6) atom to form distorted WO6 octahedra that share corners with two equivalent Sr(6)O6 octahedra,  an edgeedge with one Sr(2)O6 pentagonal pyramid, and  a faceface with one W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-59°. In the fourth W site, W(4) is bonded to one O(12), one O(14), one O(15), one O(3), one O(7), and one O(8) atom to form distorted WO6 octahedra that share corners with two equivalent Sr(2)O6 pentagonal pyramids,  an edgeedge with one Sr(6)O6 octahedra, and  a faceface with one W(1)O6 octahedra. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Sr(1), one Sr(3), and one W(3) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Sr(1), one Sr(2), one Sr(5), and one W(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one W(1), and one W(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Sr(2), one Sr(5), and one W(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Sr(1), one W(2), and one W(3) atom. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Sr(2), one Sr(5), one W(2), and one W(3) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(4), and one W(4) atom. In the eighth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Sr(3), one Sr(6), and one W(4) atom. In the ninth O site, O(9) is bonded to one Sr(3), one Sr(5), one Sr(6), and one W(1) atom to form distorted corner-sharing OSr3W tetrahedra. In the tenth O site, O(10) is bonded to one Sr(1), one Sr(2), one Sr(4), and one W(3) atom to form corner-sharing OSr3W tetrahedra. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Sr(6), one Mg(1), and one W(2) atom. In the twelfth O site, O(12) is bonded in a rectangular see-saw-like geometry to one Sr(5), one Sr(6), one W(1), and one W(4) atom. In the thirteenth O site, O(13) is bonded to one Sr(3), one Sr(4), one Mg(1), and one W(2) atom to form distorted corner-sharing OSr2MgW tetrahedra. In the fourteenth O site, O(14) is bonded in a 5-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), one W(1), and one W(4) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Sr(5), one Mg(1), and one W(4) atom. In the sixteenth O site, O(16) is bonded in a rectangular see-saw-like geometry to one Sr(4), one Sr(6), one W(2), and one W(3) atom. In the seventeenth O site, O(17) is bonded in a distorted rectangular see-saw-like geometry to one Sr(4), one Sr(6), one Mg(1), and one W(3) atom. In the eighteenth O site, O(18) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(4), and one W(1) atom. is represented by the CIF card [CIF]
data_Sr6Mg(W2O9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.495
_cell_length_b   8.896
_cell_length_c   7.252
_cell_angle_alpha   79.973
_cell_angle_beta   81.274
_cell_angle_gamma   77.876
_symmetry_Int_Tables_number   1
_cell_volume   462.230
_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  0.220  0.009  0.733  1.0
  Sr  Sr1  1  0.157  0.480  0.787  1.0
  Sr  Sr2  1  0.470  0.710  0.132  1.0
  Sr  Sr3  1  0.721  0.284  0.937  1.0
  Sr  Sr4  1  0.989  0.650  0.258  1.0
  Sr  Sr5  1  0.654  0.998  0.360  1.0
  Mg  Mg6  1  0.736  0.327  0.392  1.0
  W  W7  1  0.830  0.836  0.823  1.0
  W  W8  1  0.348  0.339  0.330  1.0
  W  W9  1  0.148  0.154  0.160  1.0
  W  W10  1  0.639  0.642  0.650  1.0
  O  O11  1  0.211  0.943  0.135  1.0
  O  O12  1  0.076  0.761  0.861  1.0
  O  O13  1  0.556  0.838  0.786  1.0
  O  O14  1  0.237  0.522  0.433  1.0
  O  O15  1  0.185  0.173  0.429  1.0
  O  O16  1  0.138  0.402  0.148  1.0
  O  O17  1  0.477  0.527  0.788  1.0
  O  O18  1  0.513  0.757  0.454  1.0
  O  O19  1  0.745  0.838  0.083  1.0
  O  O20  1  0.088  0.223  0.893  1.0
  O  O21  1  0.522  0.227  0.512  1.0
  O  O22  1  0.852  0.783  0.557  1.0
  O  O23  1  0.567  0.434  0.202  1.0
  O  O24  1  0.801  0.593  0.861  1.0
  O  O25  1  0.793  0.489  0.515  1.0
  O  O26  1  0.433  0.179  0.139  1.0
  O  O27  1  0.876  0.173  0.234  1.0
  O  O28  1  0.841  0.041  0.747  1.0
[/CIF]
.