The structure described by Ca2Zn16Al crystallizes in the trigonal R3m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 19-coordinate geometry to one Zn(5), three equivalent Zn(1), three equivalent Zn(4), six equivalent Zn(2), and six equivalent Zn(3) atoms. In the second Ca site, Ca(2) is bonded in a 19-coordinate geometry to three equivalent Zn(2), three equivalent Zn(4), six equivalent Zn(1), six equivalent Zn(3), and one Al(1) atom. There are five inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one Ca(1), two equivalent Ca(2), two equivalent Zn(2), two equivalent Zn(4), four equivalent Zn(3), and one Al(1) atom to form ZnCa3AlZn8 cuboctahedra that share corners with two equivalent Zn(1)Ca3AlZn8 cuboctahedra, corners with five equivalent Zn(4)Ca2AlZn9 cuboctahedra, corners with eight equivalent Zn(2)Ca3Zn9 cuboctahedra,  an edgeedge with one Zn(2)Ca3Zn9 cuboctahedra, edges with three equivalent Zn(4)Ca2AlZn9 cuboctahedra, edges with four equivalent Zn(1)Ca3AlZn8 cuboctahedra, faces with three equivalent Zn(4)Ca2AlZn9 cuboctahedra, faces with three equivalent Zn(2)Ca3Zn9 cuboctahedra, and faces with four equivalent Zn(1)Ca3AlZn8 cuboctahedra. In the second Zn site, Zn(2) is bonded to one Ca(2), two equivalent Ca(1), one Zn(5), two equivalent Zn(1), two equivalent Zn(4), and four equivalent Zn(3) atoms to form distorted ZnCa3Zn9 cuboctahedra that share corners with two equivalent Zn(2)Ca3Zn9 cuboctahedra, corners with five equivalent Zn(4)Ca2AlZn9 cuboctahedra, corners with eight equivalent Zn(1)Ca3AlZn8 cuboctahedra,  an edgeedge with one Zn(1)Ca3AlZn8 cuboctahedra, edges with three equivalent Zn(4)Ca2AlZn9 cuboctahedra, edges with four equivalent Zn(2)Ca3Zn9 cuboctahedra, faces with three equivalent Zn(4)Ca2AlZn9 cuboctahedra, faces with three equivalent Zn(1)Ca3AlZn8 cuboctahedra, and faces with four equivalent Zn(2)Ca3Zn9 cuboctahedra. In the third Zn site, Zn(3) is bonded in a 12-coordinate geometry to one Ca(1), one Ca(2), one Zn(5), two equivalent Zn(1), two equivalent Zn(2), two equivalent Zn(3), two equivalent Zn(4), and one Al(1) atom. In the fourth Zn site, Zn(4) is bonded to one Ca(1), one Ca(2), one Zn(5), two equivalent Zn(1), two equivalent Zn(2), four equivalent Zn(3), and one Al(1) atom to form ZnCa2AlZn9 cuboctahedra that share corners with four equivalent Zn(4)Ca2AlZn9 cuboctahedra, corners with five equivalent Zn(1)Ca3AlZn8 cuboctahedra, corners with five equivalent Zn(2)Ca3Zn9 cuboctahedra, edges with three equivalent Zn(1)Ca3AlZn8 cuboctahedra, edges with three equivalent Zn(2)Ca3Zn9 cuboctahedra, faces with three equivalent Zn(1)Ca3AlZn8 cuboctahedra, faces with three equivalent Zn(2)Ca3Zn9 cuboctahedra, and faces with four equivalent Zn(4)Ca2AlZn9 cuboctahedra. In the fifth Zn site, Zn(5) is bonded in a 14-coordinate geometry to one Ca(1), three equivalent Zn(2), three equivalent Zn(4), six equivalent Zn(3), and one Al(1) atom. Al(1) is bonded in a 14-coordinate geometry to one Ca(2), one Zn(5), three equivalent Zn(1), three equivalent Zn(4), and six equivalent Zn(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2AlZn16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.763
_cell_length_b   6.763
_cell_length_c   6.763
_cell_angle_alpha   82.910
_cell_angle_beta   82.910
_cell_angle_gamma   82.910
_symmetry_Int_Tables_number   1
_cell_volume   302.781
_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
  Ca  Ca0  1  0.662  0.662  0.662  1.0
  Ca  Ca1  1  0.339  0.339  0.339  1.0
  Al  Al2  1  0.096  0.096  0.096  1.0
  Zn  Zn3  1  0.349  0.840  0.349  1.0
  Zn  Zn4  1  0.349  0.349  0.840  1.0
  Zn  Zn5  1  0.840  0.349  0.349  1.0
  Zn  Zn6  1  0.652  0.161  0.652  1.0
  Zn  Zn7  1  0.652  0.652  0.161  1.0
  Zn  Zn8  1  0.161  0.652  0.652  1.0
  Zn  Zn9  1  0.297  0.703  0.000  1.0
  Zn  Zn10  1  0.000  0.297  0.703  1.0
  Zn  Zn11  1  0.703  0.000  0.297  1.0
  Zn  Zn12  1  0.000  0.703  0.297  1.0
  Zn  Zn13  1  0.297  0.000  0.703  1.0
  Zn  Zn14  1  0.703  0.297  0.000  1.0
  Zn  Zn15  1  1.000  1.000  0.501  1.0
  Zn  Zn16  1  0.501  1.000  1.000  1.0
  Zn  Zn17  1  1.000  0.501  1.000  1.0
  Zn  Zn18  1  0.900  0.900  0.900  1.0
[/CIF]
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The structure described by Ca2Zn16Al crystallizes in the trigonal R3m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 19-coordinate geometry to one Zn(5), three equivalent Zn(1), three equivalent Zn(4), six equivalent Zn(2), and six equivalent Zn(3) atoms. In the second Ca site, Ca(2) is bonded in a 19-coordinate geometry to three equivalent Zn(2), three equivalent Zn(4), six equivalent Zn(1), six equivalent Zn(3), and one Al(1) atom. There are five inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one Ca(1), two equivalent Ca(2), two equivalent Zn(2), two equivalent Zn(4), four equivalent Zn(3), and one Al(1) atom to form ZnCa3AlZn8 cuboctahedra that share corners with two equivalent Zn(1)Ca3AlZn8 cuboctahedra, corners with five equivalent Zn(4)Ca2AlZn9 cuboctahedra, corners with eight equivalent Zn(2)Ca3Zn9 cuboctahedra,  an edgeedge with one Zn(2)Ca3Zn9 cuboctahedra, edges with three equivalent Zn(4)Ca2AlZn9 cuboctahedra, edges with four equivalent Zn(1)Ca3AlZn8 cuboctahedra, faces with three equivalent Zn(4)Ca2AlZn9 cuboctahedra, faces with three equivalent Zn(2)Ca3Zn9 cuboctahedra, and faces with four equivalent Zn(1)Ca3AlZn8 cuboctahedra. In the second Zn site, Zn(2) is bonded to one Ca(2), two equivalent Ca(1), one Zn(5), two equivalent Zn(1), two equivalent Zn(4), and four equivalent Zn(3) atoms to form distorted ZnCa3Zn9 cuboctahedra that share corners with two equivalent Zn(2)Ca3Zn9 cuboctahedra, corners with five equivalent Zn(4)Ca2AlZn9 cuboctahedra, corners with eight equivalent Zn(1)Ca3AlZn8 cuboctahedra,  an edgeedge with one Zn(1)Ca3AlZn8 cuboctahedra, edges with three equivalent Zn(4)Ca2AlZn9 cuboctahedra, edges with four equivalent Zn(2)Ca3Zn9 cuboctahedra, faces with three equivalent Zn(4)Ca2AlZn9 cuboctahedra, faces with three equivalent Zn(1)Ca3AlZn8 cuboctahedra, and faces with four equivalent Zn(2)Ca3Zn9 cuboctahedra. In the third Zn site, Zn(3) is bonded in a 12-coordinate geometry to one Ca(1), one Ca(2), one Zn(5), two equivalent Zn(1), two equivalent Zn(2), two equivalent Zn(3), two equivalent Zn(4), and one Al(1) atom. In the fourth Zn site, Zn(4) is bonded to one Ca(1), one Ca(2), one Zn(5), two equivalent Zn(1), two equivalent Zn(2), four equivalent Zn(3), and one Al(1) atom to form ZnCa2AlZn9 cuboctahedra that share corners with four equivalent Zn(4)Ca2AlZn9 cuboctahedra, corners with five equivalent Zn(1)Ca3AlZn8 cuboctahedra, corners with five equivalent Zn(2)Ca3Zn9 cuboctahedra, edges with three equivalent Zn(1)Ca3AlZn8 cuboctahedra, edges with three equivalent Zn(2)Ca3Zn9 cuboctahedra, faces with three equivalent Zn(1)Ca3AlZn8 cuboctahedra, faces with three equivalent Zn(2)Ca3Zn9 cuboctahedra, and faces with four equivalent Zn(4)Ca2AlZn9 cuboctahedra. In the fifth Zn site, Zn(5) is bonded in a 14-coordinate geometry to one Ca(1), three equivalent Zn(2), three equivalent Zn(4), six equivalent Zn(3), and one Al(1) atom. Al(1) is bonded in a 14-coordinate geometry to one Ca(2), one Zn(5), three equivalent Zn(1), three equivalent Zn(4), and six equivalent Zn(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2AlZn16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.763
_cell_length_b   6.763
_cell_length_c   6.763
_cell_angle_alpha   82.910
_cell_angle_beta   82.910
_cell_angle_gamma   82.910
_symmetry_Int_Tables_number   1
_cell_volume   302.781
_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
  Ca  Ca0  1  0.662  0.662  0.662  1.0
  Ca  Ca1  1  0.339  0.339  0.339  1.0
  Al  Al2  1  0.096  0.096  0.096  1.0
  Zn  Zn3  1  0.349  0.840  0.349  1.0
  Zn  Zn4  1  0.349  0.349  0.840  1.0
  Zn  Zn5  1  0.840  0.349  0.349  1.0
  Zn  Zn6  1  0.652  0.161  0.652  1.0
  Zn  Zn7  1  0.652  0.652  0.161  1.0
  Zn  Zn8  1  0.161  0.652  0.652  1.0
  Zn  Zn9  1  0.297  0.703  0.000  1.0
  Zn  Zn10  1  0.000  0.297  0.703  1.0
  Zn  Zn11  1  0.703  0.000  0.297  1.0
  Zn  Zn12  1  0.000  0.703  0.297  1.0
  Zn  Zn13  1  0.297  0.000  0.703  1.0
  Zn  Zn14  1  0.703  0.297  0.000  1.0
  Zn  Zn15  1  1.000  1.000  0.501  1.0
  Zn  Zn16  1  0.501  1.000  1.000  1.0
  Zn  Zn17  1  1.000  0.501  1.000  1.0
  Zn  Zn18  1  0.900  0.900  0.900  1.0
[/CIF]
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