The compound described by Mg14SiBiO16 is Caswellsilverite-derived structured and crystallizes in the orthorhombic Cmmm space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Si(1)O6 octahedra, corners with two equivalent Bi(1)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the second Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Si(1)O6 octahedra, corners with two equivalent Bi(1)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the third Mg site, Mg(2) is bonded to one O(3), one O(4), one O(5), one O(6), and two equivalent O(1) atoms to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the fourth Mg site, Mg(3) is bonded to one O(3), one O(4), one O(6), one O(7), and two equivalent O(2) atoms to form MgO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with four equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the fifth Mg site, Mg(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(4)O6 octahedra; corners with four equivalent Mg(5)O6 octahedra;  an edgeedge with one Si(1)O6 octahedra;  an edgeedge with one Bi(1)O6 octahedra; edges with two Mg(1,1)O6 octahedra; edges with four equivalent Mg(2)O6 octahedra; and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. In the sixth Mg site, Mg(5) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(5)O6 octahedra; corners with four equivalent Mg(4)O6 octahedra;  an edgeedge with one Si(1)O6 octahedra;  an edgeedge with one Bi(1)O6 octahedra; edges with two Mg(1,1)O6 octahedra; edges with four equivalent Mg(2)O6 octahedra; and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. Si(1) is bonded to two equivalent O(5) and four equivalent O(1) atoms to form SiO6 octahedra that share corners with two equivalent Si(1)O6 octahedra; corners with four Mg(1,1)O6 octahedra; edges with two equivalent Mg(4)O6 octahedra; edges with two equivalent Mg(5)O6 octahedra; and edges with eight equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. Bi(1) is bonded to two equivalent O(7) and four equivalent O(2) atoms to form BiO6 octahedra that share corners with two equivalent Bi(1)O6 octahedra; corners with four Mg(1,1)O6 octahedra; edges with two equivalent Mg(4)O6 octahedra; edges with two equivalent Mg(5)O6 octahedra; and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(4), one Mg(5), two equivalent Mg(2), and one Si(1) atom to form OMg5Si octahedra that share corners with two equivalent O(2)Mg5Bi octahedra, corners with four equivalent O(1)Mg5Si octahedra, edges with two equivalent O(5)Mg4Si2 octahedra, edges with two equivalent O(2)Mg5Bi octahedra, edges with two equivalent O(1)Mg5Si octahedra, edges with two equivalent O(3)Mg6 octahedra, edges with two equivalent O(4)Mg6 octahedra, and edges with two equivalent O(6)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the second O site, O(2) is bonded to one Mg(1), one Mg(4), one Mg(5), two equivalent Mg(3), and one Bi(1) atom to form distorted OMg5Bi octahedra that share corners with two equivalent O(1)Mg5Si octahedra, corners with four equivalent O(2)Mg5Bi octahedra, edges with two equivalent O(7)Mg4Bi2 octahedra, edges with two equivalent O(2)Mg5Bi octahedra, edges with two equivalent O(1)Mg5Si octahedra, edges with two equivalent O(3)Mg6 octahedra, edges with two equivalent O(4)Mg6 octahedra, and edges with two equivalent O(6)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the third O site, O(3) is bonded to two equivalent Mg(2), two equivalent Mg(3), and two equivalent Mg(4) atoms to form OMg6 octahedra that share corners with two equivalent O(3)Mg6 octahedra, corners with four equivalent O(4)Mg6 octahedra,  an edgeedge with one O(7)Mg4Bi2 octahedra,  an edgeedge with one O(5)Mg4Si2 octahedra, edges with two equivalent O(6)Mg6 octahedra, edges with four equivalent O(2)Mg5Bi octahedra, and edges with four equivalent O(1)Mg5Si octahedra. The corner-sharing octahedral tilt angles range from 1-6°. In the fourth O site, O(4) is bonded to two equivalent Mg(2), two equivalent Mg(3), and two equivalent Mg(5) atoms to form OMg6 octahedra that share corners with two equivalent O(4)Mg6 octahedra, corners with four equivalent O(3)Mg6 octahedra,  an edgeedge with one O(7)Mg4Bi2 octahedra,  an edgeedge with one O(5)Mg4Si2 octahedra, edges with two equivalent O(6)Mg6 octahedra, edges with four equivalent O(2)Mg5Bi octahedra, and edges with four equivalent O(1)Mg5Si octahedra. The corner-sharing octahedral tilt angles range from 1-6°. In the fifth O site, O(5) is bonded to four equivalent Mg(2) and two equivalent Si(1) atoms to form OMg4Si2 octahedra that share corners with two equivalent O(5)Mg4Si2 octahedra, corners with four equivalent O(6)Mg6 octahedra, edges with two equivalent O(3)Mg6 octahedra, edges with two equivalent O(4)Mg6 octahedra, and edges with eight equivalent O(1)Mg5Si octahedra. The corner-sharing octahedra are not tilted. In the sixth O site, O(6) is bonded to two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(3) atoms to form OMg6 octahedra that share corners with two equivalent O(7)Mg4Bi2 octahedra, corners with two equivalent O(5)Mg4Si2 octahedra, corners with two equivalent O(6)Mg6 octahedra, edges with two equivalent O(3)Mg6 octahedra, edges with two equivalent O(4)Mg6 octahedra, edges with four equivalent O(2)Mg5Bi octahedra, and edges with four equivalent O(1)Mg5Si octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the seventh O site, O(7) is bonded to four equivalent Mg(3) and two equivalent Bi(1) atoms to form OMg4Bi2 octahedra that share corners with two equivalent O(7)Mg4Bi2 octahedra, corners with four equivalent O(6)Mg6 octahedra, edges with two equivalent O(3)Mg6 octahedra, edges with two equivalent O(4)Mg6 octahedra, and edges with eight equivalent O(2)Mg5Bi octahedra. The corner-sharing octahedral tilt angles range from 0-2°. is represented by the CIF file [CIF]
data_Mg14SiBiO16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.811
_cell_length_b   8.812
_cell_length_c   4.399
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   91.401
_symmetry_Int_Tables_number   1
_cell_volume   341.444
_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
  Mg  Mg0  1  0.000  0.500  0.000  1.0
  Mg  Mg1  1  0.500  0.000  0.000  1.0
  Mg  Mg2  1  0.001  0.251  0.500  1.0
  Mg  Mg3  1  0.999  0.749  0.500  1.0
  Mg  Mg4  1  0.504  0.235  0.500  1.0
  Mg  Mg5  1  0.496  0.765  0.500  1.0
  Mg  Mg6  1  0.251  0.001  0.500  1.0
  Mg  Mg7  1  0.235  0.504  0.500  1.0
  Mg  Mg8  1  0.749  0.999  0.500  1.0
  Mg  Mg9  1  0.765  0.496  0.500  1.0
  Mg  Mg10  1  0.247  0.247  0.000  1.0
  Mg  Mg11  1  0.241  0.759  0.000  1.0
  Mg  Mg12  1  0.759  0.241  0.000  1.0
  Mg  Mg13  1  0.753  0.753  0.000  1.0
  Si  Si14  1  0.000  0.000  0.000  1.0
  Bi  Bi15  1  0.500  0.500  0.000  1.0
  O  O16  1  0.257  0.005  0.000  1.0
  O  O17  1  0.225  0.519  0.000  1.0
  O  O18  1  0.743  0.995  0.000  1.0
  O  O19  1  0.775  0.481  0.000  1.0
  O  O20  1  0.251  0.251  0.500  1.0
  O  O21  1  0.245  0.755  0.500  1.0
  O  O22  1  0.755  0.245  0.500  1.0
  O  O23  1  0.749  0.749  0.500  1.0
  O  O24  1  0.000  0.000  0.500  1.0
  O  O25  1  0.000  0.500  0.500  1.0
  O  O26  1  0.500  0.000  0.500  1.0
  O  O27  1  0.500  0.500  0.500  1.0
  O  O28  1  0.005  0.257  0.000  1.0
  O  O29  1  0.995  0.743  0.000  1.0
  O  O30  1  0.519  0.225  0.000  1.0
  O  O31  1  0.481  0.775  0.000  1.0
[/CIF]
.
The compound described by Mg14SiBiO16 is Caswellsilverite-derived structured and crystallizes in the orthorhombic Cmmm space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Si(1)O6 octahedra, corners with two equivalent Bi(1)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the second Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Si(1)O6 octahedra, corners with two equivalent Bi(1)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the third Mg site, Mg(2) is bonded to one O(3), one O(4), one O(5), one O(6), and two equivalent O(1) atoms to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the fourth Mg site, Mg(3) is bonded to one O(3), one O(4), one O(6), one O(7), and two equivalent O(2) atoms to form MgO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with four equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the fifth Mg site, Mg(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(4)O6 octahedra; corners with four equivalent Mg(5)O6 octahedra;  an edgeedge with one Si(1)O6 octahedra;  an edgeedge with one Bi(1)O6 octahedra; edges with two Mg(1,1)O6 octahedra; edges with four equivalent Mg(2)O6 octahedra; and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. In the sixth Mg site, Mg(5) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(5)O6 octahedra; corners with four equivalent Mg(4)O6 octahedra;  an edgeedge with one Si(1)O6 octahedra;  an edgeedge with one Bi(1)O6 octahedra; edges with two Mg(1,1)O6 octahedra; edges with four equivalent Mg(2)O6 octahedra; and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. Si(1) is bonded to two equivalent O(5) and four equivalent O(1) atoms to form SiO6 octahedra that share corners with two equivalent Si(1)O6 octahedra; corners with four Mg(1,1)O6 octahedra; edges with two equivalent Mg(4)O6 octahedra; edges with two equivalent Mg(5)O6 octahedra; and edges with eight equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. Bi(1) is bonded to two equivalent O(7) and four equivalent O(2) atoms to form BiO6 octahedra that share corners with two equivalent Bi(1)O6 octahedra; corners with four Mg(1,1)O6 octahedra; edges with two equivalent Mg(4)O6 octahedra; edges with two equivalent Mg(5)O6 octahedra; and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(4), one Mg(5), two equivalent Mg(2), and one Si(1) atom to form OMg5Si octahedra that share corners with two equivalent O(2)Mg5Bi octahedra, corners with four equivalent O(1)Mg5Si octahedra, edges with two equivalent O(5)Mg4Si2 octahedra, edges with two equivalent O(2)Mg5Bi octahedra, edges with two equivalent O(1)Mg5Si octahedra, edges with two equivalent O(3)Mg6 octahedra, edges with two equivalent O(4)Mg6 octahedra, and edges with two equivalent O(6)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the second O site, O(2) is bonded to one Mg(1), one Mg(4), one Mg(5), two equivalent Mg(3), and one Bi(1) atom to form distorted OMg5Bi octahedra that share corners with two equivalent O(1)Mg5Si octahedra, corners with four equivalent O(2)Mg5Bi octahedra, edges with two equivalent O(7)Mg4Bi2 octahedra, edges with two equivalent O(2)Mg5Bi octahedra, edges with two equivalent O(1)Mg5Si octahedra, edges with two equivalent O(3)Mg6 octahedra, edges with two equivalent O(4)Mg6 octahedra, and edges with two equivalent O(6)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the third O site, O(3) is bonded to two equivalent Mg(2), two equivalent Mg(3), and two equivalent Mg(4) atoms to form OMg6 octahedra that share corners with two equivalent O(3)Mg6 octahedra, corners with four equivalent O(4)Mg6 octahedra,  an edgeedge with one O(7)Mg4Bi2 octahedra,  an edgeedge with one O(5)Mg4Si2 octahedra, edges with two equivalent O(6)Mg6 octahedra, edges with four equivalent O(2)Mg5Bi octahedra, and edges with four equivalent O(1)Mg5Si octahedra. The corner-sharing octahedral tilt angles range from 1-6°. In the fourth O site, O(4) is bonded to two equivalent Mg(2), two equivalent Mg(3), and two equivalent Mg(5) atoms to form OMg6 octahedra that share corners with two equivalent O(4)Mg6 octahedra, corners with four equivalent O(3)Mg6 octahedra,  an edgeedge with one O(7)Mg4Bi2 octahedra,  an edgeedge with one O(5)Mg4Si2 octahedra, edges with two equivalent O(6)Mg6 octahedra, edges with four equivalent O(2)Mg5Bi octahedra, and edges with four equivalent O(1)Mg5Si octahedra. The corner-sharing octahedral tilt angles range from 1-6°. In the fifth O site, O(5) is bonded to four equivalent Mg(2) and two equivalent Si(1) atoms to form OMg4Si2 octahedra that share corners with two equivalent O(5)Mg4Si2 octahedra, corners with four equivalent O(6)Mg6 octahedra, edges with two equivalent O(3)Mg6 octahedra, edges with two equivalent O(4)Mg6 octahedra, and edges with eight equivalent O(1)Mg5Si octahedra. The corner-sharing octahedra are not tilted. In the sixth O site, O(6) is bonded to two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(3) atoms to form OMg6 octahedra that share corners with two equivalent O(7)Mg4Bi2 octahedra, corners with two equivalent O(5)Mg4Si2 octahedra, corners with two equivalent O(6)Mg6 octahedra, edges with two equivalent O(3)Mg6 octahedra, edges with two equivalent O(4)Mg6 octahedra, edges with four equivalent O(2)Mg5Bi octahedra, and edges with four equivalent O(1)Mg5Si octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the seventh O site, O(7) is bonded to four equivalent Mg(3) and two equivalent Bi(1) atoms to form OMg4Bi2 octahedra that share corners with two equivalent O(7)Mg4Bi2 octahedra, corners with four equivalent O(6)Mg6 octahedra, edges with two equivalent O(3)Mg6 octahedra, edges with two equivalent O(4)Mg6 octahedra, and edges with eight equivalent O(2)Mg5Bi octahedra. The corner-sharing octahedral tilt angles range from 0-2°. is represented by the CIF file [CIF]
data_Mg14SiBiO16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.811
_cell_length_b   8.812
_cell_length_c   4.399
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   91.401
_symmetry_Int_Tables_number   1
_cell_volume   341.444
_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
  Mg  Mg0  1  0.000  0.500  0.000  1.0
  Mg  Mg1  1  0.500  0.000  0.000  1.0
  Mg  Mg2  1  0.001  0.251  0.500  1.0
  Mg  Mg3  1  0.999  0.749  0.500  1.0
  Mg  Mg4  1  0.504  0.235  0.500  1.0
  Mg  Mg5  1  0.496  0.765  0.500  1.0
  Mg  Mg6  1  0.251  0.001  0.500  1.0
  Mg  Mg7  1  0.235  0.504  0.500  1.0
  Mg  Mg8  1  0.749  0.999  0.500  1.0
  Mg  Mg9  1  0.765  0.496  0.500  1.0
  Mg  Mg10  1  0.247  0.247  0.000  1.0
  Mg  Mg11  1  0.241  0.759  0.000  1.0
  Mg  Mg12  1  0.759  0.241  0.000  1.0
  Mg  Mg13  1  0.753  0.753  0.000  1.0
  Si  Si14  1  0.000  0.000  0.000  1.0
  Bi  Bi15  1  0.500  0.500  0.000  1.0
  O  O16  1  0.257  0.005  0.000  1.0
  O  O17  1  0.225  0.519  0.000  1.0
  O  O18  1  0.743  0.995  0.000  1.0
  O  O19  1  0.775  0.481  0.000  1.0
  O  O20  1  0.251  0.251  0.500  1.0
  O  O21  1  0.245  0.755  0.500  1.0
  O  O22  1  0.755  0.245  0.500  1.0
  O  O23  1  0.749  0.749  0.500  1.0
  O  O24  1  0.000  0.000  0.500  1.0
  O  O25  1  0.000  0.500  0.500  1.0
  O  O26  1  0.500  0.000  0.500  1.0
  O  O27  1  0.500  0.500  0.500  1.0
  O  O28  1  0.005  0.257  0.000  1.0
  O  O29  1  0.995  0.743  0.000  1.0
  O  O30  1  0.519  0.225  0.000  1.0
  O  O31  1  0.481  0.775  0.000  1.0
[/CIF]
.