The compound described by Sr3(AsO4)2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(7) atom to form distorted SrO5 trigonal bipyramids that share corners with two equivalent As(2)O4 tetrahedra, corners with three equivalent As(1)O4 tetrahedra,  a cornercorner with one Sr(2)O5 trigonal bipyramid,  an edgeedge with one Sr(3)O6 octahedra, and  an edgeedge with one Sr(2)O5 trigonal bipyramid. In the second Sr site, Sr(2) is bonded to one O(1), one O(3), one O(4), one O(6), and one O(8) atom to form SrO5 trigonal bipyramids that share corners with two equivalent Sr(3)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, corners with three equivalent As(2)O4 tetrahedra,  a cornercorner with one Sr(1)O5 trigonal bipyramid, and  an edgeedge with one Sr(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 66-76°. In the third Sr site, Sr(3) is bonded to one O(2), one O(6), one O(7), one O(8), and two equivalent O(5) atoms to form distorted SrO6 octahedra that share  a cornercorner with one As(2)O4 tetrahedra, corners with three equivalent As(1)O4 tetrahedra, corners with two equivalent Sr(2)O5 trigonal bipyramids,  an edgeedge with one Sr(3)O6 octahedra,  an edgeedge with one As(2)O4 tetrahedra, and  an edgeedge with one Sr(1)O5 trigonal bipyramid. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form AsO4 tetrahedra that share corners with three equivalent Sr(3)O6 octahedra, corners with two equivalent Sr(2)O5 trigonal bipyramids, and corners with three equivalent Sr(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 47-55°. In the second As site, As(2) is bonded to one O(4), one O(6), one O(7), and one O(8) atom to form AsO4 tetrahedra that share  a cornercorner with one Sr(3)O6 octahedra, corners with two equivalent Sr(1)O5 trigonal bipyramids, corners with three equivalent Sr(2)O5 trigonal bipyramids, and  an edgeedge with one Sr(3)O6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(3), and one As(2) atom. In the second O site, O(8) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(3), and one As(2) atom. In the third O site, O(1) is bonded in a distorted trigonal planar geometry to one Sr(1), one Sr(2), and one As(1) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(3), and one As(1) atom. In the fifth O site, O(3) is bonded in a distorted trigonal planar geometry to one Sr(1), one Sr(2), and one As(1) atom. In the sixth O site, O(4) is bonded in a distorted trigonal planar geometry to one Sr(1), one Sr(2), and one As(2) atom. In the seventh O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Sr(3) and one As(1) atom. In the eighth O site, O(6) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(3), and one As(2) atom. is represented by the CIF file [CIF]
data_Sr3(AsO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.296
_cell_length_b   7.357
_cell_length_c   12.676
_cell_angle_alpha   89.408
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   960.165
_cell_formula_units_Z   4
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  0.797  0.093  0.574  1.0
  Sr  Sr1  1  0.703  0.093  0.074  1.0
  Sr  Sr2  1  0.155  0.242  0.645  1.0
  Sr  Sr3  1  0.345  0.242  0.145  1.0
  Sr  Sr4  1  0.538  0.394  0.638  1.0
  Sr  Sr5  1  0.962  0.394  0.138  1.0
  Sr  Sr6  1  0.038  0.606  0.862  1.0
  Sr  Sr7  1  0.462  0.606  0.362  1.0
  Sr  Sr8  1  0.655  0.758  0.855  1.0
  Sr  Sr9  1  0.845  0.758  0.355  1.0
  Sr  Sr10  1  0.297  0.907  0.926  1.0
  Sr  Sr11  1  0.203  0.907  0.426  1.0
  As  As12  1  0.948  0.105  0.859  1.0
  As  As13  1  0.552  0.105  0.359  1.0
  As  As14  1  0.386  0.403  0.868  1.0
  As  As15  1  0.114  0.403  0.368  1.0
  As  As16  1  0.886  0.597  0.632  1.0
  As  As17  1  0.614  0.597  0.132  1.0
  As  As18  1  0.448  0.895  0.641  1.0
  As  As19  1  0.052  0.895  0.141  1.0
  O  O20  1  0.798  0.027  0.895  1.0
  O  O21  1  0.702  0.027  0.395  1.0
  O  O22  1  0.570  0.056  0.624  1.0
  O  O23  1  0.930  0.056  0.124  1.0
  O  O24  1  0.949  0.146  0.724  1.0
  O  O25  1  0.551  0.146  0.224  1.0
  O  O26  1  0.383  0.219  0.955  1.0
  O  O27  1  0.117  0.219  0.455  1.0
  O  O28  1  0.985  0.300  0.927  1.0
  O  O29  1  0.335  0.334  0.745  1.0
  O  O30  1  0.515  0.300  0.427  1.0
  O  O31  1  0.165  0.334  0.245  1.0
  O  O32  1  0.780  0.433  0.588  1.0
  O  O33  1  0.720  0.433  0.088  1.0
  O  O34  1  0.543  0.466  0.846  1.0
  O  O35  1  0.957  0.466  0.346  1.0
  O  O36  1  0.043  0.534  0.654  1.0
  O  O37  1  0.457  0.534  0.154  1.0
  O  O38  1  0.280  0.567  0.912  1.0
  O  O39  1  0.220  0.567  0.412  1.0
  O  O40  1  0.835  0.666  0.755  1.0
  O  O41  1  0.485  0.700  0.573  1.0
  O  O42  1  0.665  0.666  0.255  1.0
  O  O43  1  0.015  0.700  0.073  1.0
  O  O44  1  0.883  0.781  0.545  1.0
  O  O45  1  0.617  0.781  0.045  1.0
  O  O46  1  0.449  0.854  0.776  1.0
  O  O47  1  0.051  0.854  0.276  1.0
  O  O48  1  0.070  0.944  0.876  1.0
  O  O49  1  0.430  0.944  0.376  1.0
  O  O50  1  0.298  0.973  0.605  1.0
  O  O51  1  0.202  0.973  0.105  1.0
[/CIF]
.
The compound described by Sr3(AsO4)2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(7) atom to form distorted SrO5 trigonal bipyramids that share corners with two equivalent As(2)O4 tetrahedra, corners with three equivalent As(1)O4 tetrahedra,  a cornercorner with one Sr(2)O5 trigonal bipyramid,  an edgeedge with one Sr(3)O6 octahedra, and  an edgeedge with one Sr(2)O5 trigonal bipyramid. In the second Sr site, Sr(2) is bonded to one O(1), one O(3), one O(4), one O(6), and one O(8) atom to form SrO5 trigonal bipyramids that share corners with two equivalent Sr(3)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, corners with three equivalent As(2)O4 tetrahedra,  a cornercorner with one Sr(1)O5 trigonal bipyramid, and  an edgeedge with one Sr(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 66-76°. In the third Sr site, Sr(3) is bonded to one O(2), one O(6), one O(7), one O(8), and two equivalent O(5) atoms to form distorted SrO6 octahedra that share  a cornercorner with one As(2)O4 tetrahedra, corners with three equivalent As(1)O4 tetrahedra, corners with two equivalent Sr(2)O5 trigonal bipyramids,  an edgeedge with one Sr(3)O6 octahedra,  an edgeedge with one As(2)O4 tetrahedra, and  an edgeedge with one Sr(1)O5 trigonal bipyramid. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form AsO4 tetrahedra that share corners with three equivalent Sr(3)O6 octahedra, corners with two equivalent Sr(2)O5 trigonal bipyramids, and corners with three equivalent Sr(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 47-55°. In the second As site, As(2) is bonded to one O(4), one O(6), one O(7), and one O(8) atom to form AsO4 tetrahedra that share  a cornercorner with one Sr(3)O6 octahedra, corners with two equivalent Sr(1)O5 trigonal bipyramids, corners with three equivalent Sr(2)O5 trigonal bipyramids, and  an edgeedge with one Sr(3)O6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(3), and one As(2) atom. In the second O site, O(8) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(3), and one As(2) atom. In the third O site, O(1) is bonded in a distorted trigonal planar geometry to one Sr(1), one Sr(2), and one As(1) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(3), and one As(1) atom. In the fifth O site, O(3) is bonded in a distorted trigonal planar geometry to one Sr(1), one Sr(2), and one As(1) atom. In the sixth O site, O(4) is bonded in a distorted trigonal planar geometry to one Sr(1), one Sr(2), and one As(2) atom. In the seventh O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Sr(3) and one As(1) atom. In the eighth O site, O(6) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(3), and one As(2) atom. is represented by the CIF file [CIF]
data_Sr3(AsO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.296
_cell_length_b   7.357
_cell_length_c   12.676
_cell_angle_alpha   89.408
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   960.165
_cell_formula_units_Z   4
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  0.797  0.093  0.574  1.0
  Sr  Sr1  1  0.703  0.093  0.074  1.0
  Sr  Sr2  1  0.155  0.242  0.645  1.0
  Sr  Sr3  1  0.345  0.242  0.145  1.0
  Sr  Sr4  1  0.538  0.394  0.638  1.0
  Sr  Sr5  1  0.962  0.394  0.138  1.0
  Sr  Sr6  1  0.038  0.606  0.862  1.0
  Sr  Sr7  1  0.462  0.606  0.362  1.0
  Sr  Sr8  1  0.655  0.758  0.855  1.0
  Sr  Sr9  1  0.845  0.758  0.355  1.0
  Sr  Sr10  1  0.297  0.907  0.926  1.0
  Sr  Sr11  1  0.203  0.907  0.426  1.0
  As  As12  1  0.948  0.105  0.859  1.0
  As  As13  1  0.552  0.105  0.359  1.0
  As  As14  1  0.386  0.403  0.868  1.0
  As  As15  1  0.114  0.403  0.368  1.0
  As  As16  1  0.886  0.597  0.632  1.0
  As  As17  1  0.614  0.597  0.132  1.0
  As  As18  1  0.448  0.895  0.641  1.0
  As  As19  1  0.052  0.895  0.141  1.0
  O  O20  1  0.798  0.027  0.895  1.0
  O  O21  1  0.702  0.027  0.395  1.0
  O  O22  1  0.570  0.056  0.624  1.0
  O  O23  1  0.930  0.056  0.124  1.0
  O  O24  1  0.949  0.146  0.724  1.0
  O  O25  1  0.551  0.146  0.224  1.0
  O  O26  1  0.383  0.219  0.955  1.0
  O  O27  1  0.117  0.219  0.455  1.0
  O  O28  1  0.985  0.300  0.927  1.0
  O  O29  1  0.335  0.334  0.745  1.0
  O  O30  1  0.515  0.300  0.427  1.0
  O  O31  1  0.165  0.334  0.245  1.0
  O  O32  1  0.780  0.433  0.588  1.0
  O  O33  1  0.720  0.433  0.088  1.0
  O  O34  1  0.543  0.466  0.846  1.0
  O  O35  1  0.957  0.466  0.346  1.0
  O  O36  1  0.043  0.534  0.654  1.0
  O  O37  1  0.457  0.534  0.154  1.0
  O  O38  1  0.280  0.567  0.912  1.0
  O  O39  1  0.220  0.567  0.412  1.0
  O  O40  1  0.835  0.666  0.755  1.0
  O  O41  1  0.485  0.700  0.573  1.0
  O  O42  1  0.665  0.666  0.255  1.0
  O  O43  1  0.015  0.700  0.073  1.0
  O  O44  1  0.883  0.781  0.545  1.0
  O  O45  1  0.617  0.781  0.045  1.0
  O  O46  1  0.449  0.854  0.776  1.0
  O  O47  1  0.051  0.854  0.276  1.0
  O  O48  1  0.070  0.944  0.876  1.0
  O  O49  1  0.430  0.944  0.376  1.0
  O  O50  1  0.298  0.973  0.605  1.0
  O  O51  1  0.202  0.973  0.105  1.0
[/CIF]
.