The material structure described by RbMg14Nb crystallizes in the orthorhombic Amm2 space group. Rb(1) is bonded to two equivalent Mg(6), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Nb(1) atoms to form RbMg10Nb2 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Rb(1)Mg10Nb2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Nb(1)Rb2Mg10 cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, edges with four equivalent Mg(6)RbMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(6)RbMg11 cuboctahedra, faces with two equivalent Nb(1)Rb2Mg10 cuboctahedra, faces with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, and faces with six equivalent Mg(7)Mg11Nb cuboctahedra. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Nb(1)Rb2Mg10 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(6)RbMg11 cuboctahedra, faces with two equivalent Rb(1)Mg10Nb2 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(6)RbMg11 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(7)Mg11Nb cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Rb(1)Mg10Nb2 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(7)Mg11Nb cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(7)Mg11Nb cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Nb(1)Rb2Mg10 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(6)RbMg11 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Rb(1), two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and two equivalent Nb(1) atoms to form distorted MgRb2Mg8Nb2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with six equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, edges with two equivalent Rb(1)Mg10Nb2 cuboctahedra, edges with two equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, edges with two equivalent Nb(1)Rb2Mg10 cuboctahedra, edges with four equivalent Mg(7)Mg11Nb cuboctahedra, edges with four equivalent Mg(6)RbMg11 cuboctahedra, faces with two equivalent Rb(1)Mg10Nb2 cuboctahedra, faces with two equivalent Mg(7)Mg11Nb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, faces with two equivalent Mg(6)RbMg11 cuboctahedra, and faces with two equivalent Nb(1)Rb2Mg10 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Rb(1)Mg10Nb2 cuboctahedra, corners with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, corners with four equivalent Nb(1)Rb2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(7)Mg11Nb cuboctahedra, edges with four equivalent Mg(6)RbMg11 cuboctahedra, faces with two equivalent Mg(7)Mg11Nb cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, and faces with two equivalent Mg(6)RbMg11 cuboctahedra. In the fifth Mg site, Mg(5) is bonded in a 2-coordinate geometry to one Rb(1), one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(6), two equivalent Mg(7), and one Nb(1) atom. In the sixth Mg site, Mg(6) is bonded to one Rb(1), one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), and four equivalent Mg(5) atoms to form distorted MgRbMg11 cuboctahedra that share corners with four equivalent Mg(7)Mg11Nb cuboctahedra, corners with six equivalent Mg(6)RbMg11 cuboctahedra, edges with two equivalent Rb(1)Mg10Nb2 cuboctahedra, edges with two equivalent Mg(7)Mg11Nb cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra,  a faceface with one Rb(1)Mg10Nb2 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(7)Mg11Nb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, faces with two equivalent Mg(6)RbMg11 cuboctahedra, faces with three equivalent Mg(2)Mg12 cuboctahedra, and faces with three equivalent Nb(1)Rb2Mg10 cuboctahedra. In the seventh Mg site, Mg(7) is bonded to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), four equivalent Mg(5), and one Nb(1) atom to form distorted MgMg11Nb cuboctahedra that share corners with four equivalent Mg(6)RbMg11 cuboctahedra, corners with six equivalent Mg(7)Mg11Nb cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(6)RbMg11 cuboctahedra, edges with two equivalent Nb(1)Rb2Mg10 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Nb(1)Rb2Mg10 cuboctahedra, faces with two equivalent Mg(7)Mg11Nb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, faces with two equivalent Mg(6)RbMg11 cuboctahedra, faces with three equivalent Rb(1)Mg10Nb2 cuboctahedra, and faces with three equivalent Mg(1)Mg12 cuboctahedra. Nb(1) is bonded to two equivalent Rb(1), two equivalent Mg(7), four equivalent Mg(3), and four equivalent Mg(5) atoms to form NbRb2Mg10 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Nb(1)Rb2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Rb(1)Mg10Nb2 cuboctahedra, edges with four equivalent Mg(7)Mg11Nb cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, faces with two equivalent Rb(1)Mg10Nb2 cuboctahedra, faces with two equivalent Mg(7)Mg11Nb cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, and faces with six equivalent Mg(6)RbMg11 cuboctahedra. is represented by the CIF file [CIF]
data_RbMg14Nb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.505
_cell_length_b   6.686
_cell_length_c   10.368
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.928
_symmetry_Int_Tables_number   1
_cell_volume   386.835
_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
  Rb  Rb0  1  0.160  0.330  0.125  1.0
  Mg  Mg1  1  0.171  0.336  0.625  1.0
  Mg  Mg2  1  0.166  0.833  0.625  1.0
  Mg  Mg3  1  0.663  0.332  0.125  1.0
  Mg  Mg4  1  0.668  0.339  0.625  1.0
  Mg  Mg5  1  0.663  0.832  0.125  1.0
  Mg  Mg6  1  0.668  0.829  0.625  1.0
  Mg  Mg7  1  0.332  0.149  0.381  1.0
  Mg  Mg8  1  0.332  0.149  0.869  1.0
  Mg  Mg9  1  0.332  0.683  0.381  1.0
  Mg  Mg10  1  0.332  0.683  0.869  1.0
  Mg  Mg11  1  0.818  0.159  0.391  1.0
  Mg  Mg12  1  0.818  0.159  0.859  1.0
  Mg  Mg13  1  0.843  0.672  0.366  1.0
  Mg  Mg14  1  0.843  0.672  0.884  1.0
  Nb  Nb15  1  0.192  0.846  0.125  1.0
[/CIF]
.
The material structure described by RbMg14Nb crystallizes in the orthorhombic Amm2 space group. Rb(1) is bonded to two equivalent Mg(6), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Nb(1) atoms to form RbMg10Nb2 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Rb(1)Mg10Nb2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Nb(1)Rb2Mg10 cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, edges with four equivalent Mg(6)RbMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(6)RbMg11 cuboctahedra, faces with two equivalent Nb(1)Rb2Mg10 cuboctahedra, faces with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, and faces with six equivalent Mg(7)Mg11Nb cuboctahedra. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Nb(1)Rb2Mg10 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(6)RbMg11 cuboctahedra, faces with two equivalent Rb(1)Mg10Nb2 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(6)RbMg11 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(7)Mg11Nb cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Rb(1)Mg10Nb2 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(7)Mg11Nb cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(7)Mg11Nb cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Nb(1)Rb2Mg10 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(6)RbMg11 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Rb(1), two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and two equivalent Nb(1) atoms to form distorted MgRb2Mg8Nb2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with six equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, edges with two equivalent Rb(1)Mg10Nb2 cuboctahedra, edges with two equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, edges with two equivalent Nb(1)Rb2Mg10 cuboctahedra, edges with four equivalent Mg(7)Mg11Nb cuboctahedra, edges with four equivalent Mg(6)RbMg11 cuboctahedra, faces with two equivalent Rb(1)Mg10Nb2 cuboctahedra, faces with two equivalent Mg(7)Mg11Nb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, faces with two equivalent Mg(6)RbMg11 cuboctahedra, and faces with two equivalent Nb(1)Rb2Mg10 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Rb(1)Mg10Nb2 cuboctahedra, corners with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, corners with four equivalent Nb(1)Rb2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(7)Mg11Nb cuboctahedra, edges with four equivalent Mg(6)RbMg11 cuboctahedra, faces with two equivalent Mg(7)Mg11Nb cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, and faces with two equivalent Mg(6)RbMg11 cuboctahedra. In the fifth Mg site, Mg(5) is bonded in a 2-coordinate geometry to one Rb(1), one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(6), two equivalent Mg(7), and one Nb(1) atom. In the sixth Mg site, Mg(6) is bonded to one Rb(1), one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), and four equivalent Mg(5) atoms to form distorted MgRbMg11 cuboctahedra that share corners with four equivalent Mg(7)Mg11Nb cuboctahedra, corners with six equivalent Mg(6)RbMg11 cuboctahedra, edges with two equivalent Rb(1)Mg10Nb2 cuboctahedra, edges with two equivalent Mg(7)Mg11Nb cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra,  a faceface with one Rb(1)Mg10Nb2 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(7)Mg11Nb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, faces with two equivalent Mg(6)RbMg11 cuboctahedra, faces with three equivalent Mg(2)Mg12 cuboctahedra, and faces with three equivalent Nb(1)Rb2Mg10 cuboctahedra. In the seventh Mg site, Mg(7) is bonded to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), four equivalent Mg(5), and one Nb(1) atom to form distorted MgMg11Nb cuboctahedra that share corners with four equivalent Mg(6)RbMg11 cuboctahedra, corners with six equivalent Mg(7)Mg11Nb cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(6)RbMg11 cuboctahedra, edges with two equivalent Nb(1)Rb2Mg10 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Nb(1)Rb2Mg10 cuboctahedra, faces with two equivalent Mg(7)Mg11Nb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, faces with two equivalent Mg(6)RbMg11 cuboctahedra, faces with three equivalent Rb(1)Mg10Nb2 cuboctahedra, and faces with three equivalent Mg(1)Mg12 cuboctahedra. Nb(1) is bonded to two equivalent Rb(1), two equivalent Mg(7), four equivalent Mg(3), and four equivalent Mg(5) atoms to form NbRb2Mg10 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Nb(1)Rb2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Rb(1)Mg10Nb2 cuboctahedra, edges with four equivalent Mg(7)Mg11Nb cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, faces with two equivalent Rb(1)Mg10Nb2 cuboctahedra, faces with two equivalent Mg(7)Mg11Nb cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with four equivalent Mg(3)Rb2Mg8Nb2 cuboctahedra, and faces with six equivalent Mg(6)RbMg11 cuboctahedra. is represented by the CIF file [CIF]
data_RbMg14Nb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.505
_cell_length_b   6.686
_cell_length_c   10.368
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.928
_symmetry_Int_Tables_number   1
_cell_volume   386.835
_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
  Rb  Rb0  1  0.160  0.330  0.125  1.0
  Mg  Mg1  1  0.171  0.336  0.625  1.0
  Mg  Mg2  1  0.166  0.833  0.625  1.0
  Mg  Mg3  1  0.663  0.332  0.125  1.0
  Mg  Mg4  1  0.668  0.339  0.625  1.0
  Mg  Mg5  1  0.663  0.832  0.125  1.0
  Mg  Mg6  1  0.668  0.829  0.625  1.0
  Mg  Mg7  1  0.332  0.149  0.381  1.0
  Mg  Mg8  1  0.332  0.149  0.869  1.0
  Mg  Mg9  1  0.332  0.683  0.381  1.0
  Mg  Mg10  1  0.332  0.683  0.869  1.0
  Mg  Mg11  1  0.818  0.159  0.391  1.0
  Mg  Mg12  1  0.818  0.159  0.859  1.0
  Mg  Mg13  1  0.843  0.672  0.366  1.0
  Mg  Mg14  1  0.843  0.672  0.884  1.0
  Nb  Nb15  1  0.192  0.846  0.125  1.0
[/CIF]
.