The material structure described by Ca2FeAl2Si3O13 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one O(5), one O(7), two equivalent O(1), and two equivalent O(3) atoms. In the second Ca site, Ca(2) is bonded in a 10-coordinate geometry to one O(10), one O(7), two equivalent O(3), two equivalent O(8), and four equivalent O(2) atoms. Fe(1) is bonded to one O(4), one O(8), two equivalent O(1), and two equivalent O(2) atoms to form distorted FeO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and edges with two equivalent Al(1)O6 octahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form AlO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with two equivalent Al(1)O6 octahedra. In the second Al site, Al(2) is bonded to two equivalent O(10), two equivalent O(3), and two equivalent O(6) atoms to form AlO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and edges with two equivalent Al(2)O6 octahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(7), one O(9), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. In the second Si site, Si(2) is bonded to one O(8), one O(9), and two equivalent O(3) atoms to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra, and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-53°. In the third Si site, Si(3) is bonded to one O(5), one O(6), and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, and corners with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. There are ten inequivalent O sites. In the first O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Al(2) and one Si(3) atom. In the second O site, O(7) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(2), and one Si(1) atom. In the third O site, O(8) is bonded in a bent 150 degrees geometry to two equivalent Ca(2), one Fe(1), and one Si(2) atom. In the fourth O site, O(9) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Ca(2) and two equivalent Al(2) atoms. In the sixth O site, O(1) is bonded to one Ca(1), one Fe(1), one Al(1), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OCaAlFeSi tetrahedra. In the seventh O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ca(2), one Fe(1), and one Si(3) atom. In the eighth O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), one Al(2), and one Si(2) atom. In the ninth O site, O(4) is bonded in a trigonal non-coplanar geometry to one Fe(1) and two equivalent Al(1) atoms. In the tenth O site, O(5) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Al(1), and one Si(3) atom. is represented by the CIF file [CIF]
data_Ca2Al2FeSi3O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.714
_cell_length_b   8.993
_cell_length_c   10.396
_cell_angle_alpha   116.129
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   479.619
_cell_formula_units_Z   2
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
  Ca  Ca0  1  0.250  0.239  0.849  1.0
  Ca  Ca1  1  0.750  0.761  0.151  1.0
  Ca  Ca2  1  0.250  0.402  0.576  1.0
  Ca  Ca3  1  0.750  0.598  0.424  1.0
  Al  Al4  1  0.500  0.000  0.000  1.0
  Al  Al5  1  0.000  0.000  0.000  1.0
  Al  Al6  1  0.500  0.000  0.500  1.0
  Al  Al7  1  0.000  0.000  0.500  1.0
  Fe  Fe8  1  0.750  0.709  0.773  1.0
  Fe  Fe9  1  0.250  0.291  0.227  1.0
  Si  Si10  1  0.250  0.660  0.952  1.0
  Si  Si11  1  0.750  0.340  0.048  1.0
  Si  Si12  1  0.750  0.315  0.728  1.0
  Si  Si13  1  0.250  0.685  0.272  1.0
  Si  Si14  1  0.250  0.814  0.680  1.0
  Si  Si15  1  0.750  0.186  0.320  1.0
  O  O16  1  0.493  0.767  0.960  1.0
  O  O17  1  0.993  0.233  0.040  1.0
  O  O18  1  0.507  0.233  0.040  1.0
  O  O19  1  0.007  0.767  0.960  1.0
  O  O20  1  0.479  0.689  0.641  1.0
  O  O21  1  0.979  0.311  0.359  1.0
  O  O22  1  0.521  0.311  0.359  1.0
  O  O23  1  0.021  0.689  0.641  1.0
  O  O24  1  0.517  0.200  0.664  1.0
  O  O25  1  0.017  0.800  0.336  1.0
  O  O26  1  0.483  0.800  0.336  1.0
  O  O27  1  0.983  0.200  0.664  1.0
  O  O28  1  0.750  0.947  0.876  1.0
  O  O29  1  0.250  0.053  0.124  1.0
  O  O30  1  0.250  0.955  0.853  1.0
  O  O31  1  0.750  0.045  0.147  1.0
  O  O32  1  0.250  0.928  0.592  1.0
  O  O33  1  0.750  0.072  0.408  1.0
  O  O34  1  0.250  0.482  0.819  1.0
  O  O35  1  0.750  0.518  0.181  1.0
  O  O36  1  0.750  0.472  0.693  1.0
  O  O37  1  0.250  0.528  0.307  1.0
  O  O38  1  0.750  0.373  0.903  1.0
  O  O39  1  0.250  0.627  0.097  1.0
  O  O40  1  0.750  0.904  0.551  1.0
  O  O41  1  0.250  0.096  0.449  1.0
[/CIF]
.
The material structure described by Ca2FeAl2Si3O13 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one O(5), one O(7), two equivalent O(1), and two equivalent O(3) atoms. In the second Ca site, Ca(2) is bonded in a 10-coordinate geometry to one O(10), one O(7), two equivalent O(3), two equivalent O(8), and four equivalent O(2) atoms. Fe(1) is bonded to one O(4), one O(8), two equivalent O(1), and two equivalent O(2) atoms to form distorted FeO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and edges with two equivalent Al(1)O6 octahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form AlO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with two equivalent Al(1)O6 octahedra. In the second Al site, Al(2) is bonded to two equivalent O(10), two equivalent O(3), and two equivalent O(6) atoms to form AlO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and edges with two equivalent Al(2)O6 octahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(7), one O(9), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. In the second Si site, Si(2) is bonded to one O(8), one O(9), and two equivalent O(3) atoms to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra, and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-53°. In the third Si site, Si(3) is bonded to one O(5), one O(6), and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, and corners with two equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. There are ten inequivalent O sites. In the first O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Al(2) and one Si(3) atom. In the second O site, O(7) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(2), and one Si(1) atom. In the third O site, O(8) is bonded in a bent 150 degrees geometry to two equivalent Ca(2), one Fe(1), and one Si(2) atom. In the fourth O site, O(9) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Ca(2) and two equivalent Al(2) atoms. In the sixth O site, O(1) is bonded to one Ca(1), one Fe(1), one Al(1), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OCaAlFeSi tetrahedra. In the seventh O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ca(2), one Fe(1), and one Si(3) atom. In the eighth O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), one Al(2), and one Si(2) atom. In the ninth O site, O(4) is bonded in a trigonal non-coplanar geometry to one Fe(1) and two equivalent Al(1) atoms. In the tenth O site, O(5) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Al(1), and one Si(3) atom. is represented by the CIF file [CIF]
data_Ca2Al2FeSi3O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.714
_cell_length_b   8.993
_cell_length_c   10.396
_cell_angle_alpha   116.129
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   479.619
_cell_formula_units_Z   2
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
  Ca  Ca0  1  0.250  0.239  0.849  1.0
  Ca  Ca1  1  0.750  0.761  0.151  1.0
  Ca  Ca2  1  0.250  0.402  0.576  1.0
  Ca  Ca3  1  0.750  0.598  0.424  1.0
  Al  Al4  1  0.500  0.000  0.000  1.0
  Al  Al5  1  0.000  0.000  0.000  1.0
  Al  Al6  1  0.500  0.000  0.500  1.0
  Al  Al7  1  0.000  0.000  0.500  1.0
  Fe  Fe8  1  0.750  0.709  0.773  1.0
  Fe  Fe9  1  0.250  0.291  0.227  1.0
  Si  Si10  1  0.250  0.660  0.952  1.0
  Si  Si11  1  0.750  0.340  0.048  1.0
  Si  Si12  1  0.750  0.315  0.728  1.0
  Si  Si13  1  0.250  0.685  0.272  1.0
  Si  Si14  1  0.250  0.814  0.680  1.0
  Si  Si15  1  0.750  0.186  0.320  1.0
  O  O16  1  0.493  0.767  0.960  1.0
  O  O17  1  0.993  0.233  0.040  1.0
  O  O18  1  0.507  0.233  0.040  1.0
  O  O19  1  0.007  0.767  0.960  1.0
  O  O20  1  0.479  0.689  0.641  1.0
  O  O21  1  0.979  0.311  0.359  1.0
  O  O22  1  0.521  0.311  0.359  1.0
  O  O23  1  0.021  0.689  0.641  1.0
  O  O24  1  0.517  0.200  0.664  1.0
  O  O25  1  0.017  0.800  0.336  1.0
  O  O26  1  0.483  0.800  0.336  1.0
  O  O27  1  0.983  0.200  0.664  1.0
  O  O28  1  0.750  0.947  0.876  1.0
  O  O29  1  0.250  0.053  0.124  1.0
  O  O30  1  0.250  0.955  0.853  1.0
  O  O31  1  0.750  0.045  0.147  1.0
  O  O32  1  0.250  0.928  0.592  1.0
  O  O33  1  0.750  0.072  0.408  1.0
  O  O34  1  0.250  0.482  0.819  1.0
  O  O35  1  0.750  0.518  0.181  1.0
  O  O36  1  0.750  0.472  0.693  1.0
  O  O37  1  0.250  0.528  0.307  1.0
  O  O38  1  0.750  0.373  0.903  1.0
  O  O39  1  0.250  0.627  0.097  1.0
  O  O40  1  0.750  0.904  0.551  1.0
  O  O41  1  0.250  0.096  0.449  1.0
[/CIF]
.