data_Sc2TiNb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.0
_cell_length_b   3.0
_cell_length_c   9.07
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Sc2TiNb
_chemical_formula_sum   'Sc2 Ti1 Nb1'
_cell_volume   81.35
_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
  Sc  Sc1  1  0.5  0.5  0.8  1.0
  Sc  Sc2  1  0.5  0.5  0.26  1.0
  Ti  Ti3  1  0.0  0.0  0.0  1.0
  Nb  Nb0  1  0.0  0.0  0.53  1.0

data_Sc2TiNb
_symmetry_space_group_name_H-M   P4mm
_cell_length_a   3.0
_cell_length_b   3.0
_cell_length_c   9.07
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   99
_chemical_formula_structural   Sc2TiNb
_chemical_formula_sum   'Sc2 Ti1 Nb1'
_cell_volume   81.35
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x, z'
  3  '-x, -y, z'
  4  'y, -x, z'
  5  '-x, y, z'
  6  'y, x, z'
  7  'x, -y, z'
  8  '-y, -x, 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
  Sc  Sc0  1  0.5  0.5  0.26  1.0
  Sc  Sc1  1  0.5  0.5  0.8  1.0
  Ti  Ti2  1  0.0  0.0  0.0  1.0
  Nb  Nb3  1  0.0  0.0  0.53  1.0

Sc Sc Ti Nb
Sc2TiNb crystallizes in the monoclinic Cm space group. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to four equivalent Sc(1), four equivalent Ti(1), and four equivalent Nb(1) atoms to form distorted ScSc4Ti4Nb4 cuboctahedra that share corners with four equivalent Sc(1)Sc4Ti4Nb4 cuboctahedra, corners with eight equivalent Sc(2)Sc4Ti4Nb4 cuboctahedra, edges with eight equivalent Sc(2)Sc4Ti4Nb4 cuboctahedra, edges with eight equivalent Ti(1)Sc8Ti4 cuboctahedra, edges with eight equivalent Nb(1)Sc8Nb4 cuboctahedra, faces with two equivalent Sc(2)Sc4Ti4Nb4 cuboctahedra, faces with four equivalent Ti(1)Sc8Ti4 cuboctahedra, faces with four equivalent Nb(1)Sc8Nb4 cuboctahedra, and faces with eight equivalent Sc(1)Sc4Ti4Nb4 cuboctahedra. All Sc(1)-Sc(1) bond lengths are 3.00 Å. There are a spread of Sc(1)-Ti(1) bond distances ranging from 2.76-2.78 Å. There is one shorter (3.23 Å) and three longer (3.24 Å) Sc(1)-Nb(1) bond lengths. In the second Sc site, Sc(2) is bonded to four equivalent Sc(2), four equivalent Ti(1), and four equivalent Nb(1) atoms to form ScSc4Ti4Nb4 cuboctahedra that share corners with four equivalent Sc(2)Sc4Ti4Nb4 cuboctahedra, corners with eight equivalent Sc(1)Sc4Ti4Nb4 cuboctahedra, edges with eight equivalent Sc(1)Sc4Ti4Nb4 cuboctahedra, edges with eight equivalent Ti(1)Sc8Ti4 cuboctahedra, edges with eight equivalent Nb(1)Sc8Nb4 cuboctahedra, faces with two equivalent Sc(1)Sc4Ti4Nb4 cuboctahedra, faces with four equivalent Ti(1)Sc8Ti4 cuboctahedra, faces with four equivalent Nb(1)Sc8Nb4 cuboctahedra, and faces with eight equivalent Sc(2)Sc4Ti4Nb4 cuboctahedra. All Sc(2)-Sc(2) bond lengths are 3.00 Å. There is one shorter (3.19 Å) and three longer (3.20 Å) Sc(2)-Ti(1) bond lengths. There is one shorter (3.23 Å) and three longer (3.24 Å) Sc(2)-Nb(1) bond lengths. Ti(1) is bonded to four equivalent Sc(1), four equivalent Sc(2), and four equivalent Ti(1) atoms to form distorted TiSc8Ti4 cuboctahedra that share corners with four equivalent Ti(1)Sc8Ti4 cuboctahedra, corners with eight equivalent Nb(1)Sc8Nb4 cuboctahedra, edges with eight equivalent Sc(1)Sc4Ti4Nb4 cuboctahedra, edges with eight equivalent Sc(2)Sc4Ti4Nb4 cuboctahedra, edges with eight equivalent Nb(1)Sc8Nb4 cuboctahedra, faces with two equivalent Nb(1)Sc8Nb4 cuboctahedra, faces with four equivalent Sc(1)Sc4Ti4Nb4 cuboctahedra, faces with four equivalent Sc(2)Sc4Ti4Nb4 cuboctahedra, and faces with eight equivalent Ti(1)Sc8Ti4 cuboctahedra. All Ti(1)-Ti(1) bond lengths are 3.00 Å. Nb(1) is bonded to four equivalent Sc(1), four equivalent Sc(2), and four equivalent Nb(1) atoms to form NbSc8Nb4 cuboctahedra that share corners with four equivalent Nb(1)Sc8Nb4 cuboctahedra, corners with eight equivalent Ti(1)Sc8Ti4 cuboctahedra, edges with eight equivalent Sc(1)Sc4Ti4Nb4 cuboctahedra, edges with eight equivalent Sc(2)Sc4Ti4Nb4 cuboctahedra, edges with eight equivalent Ti(1)Sc8Ti4 cuboctahedra, faces with two equivalent Ti(1)Sc8Ti4 cuboctahedra, faces with four equivalent Sc(1)Sc4Ti4Nb4 cuboctahedra, faces with four equivalent Sc(2)Sc4Ti4Nb4 cuboctahedra, and faces with eight equivalent Nb(1)Sc8Nb4 cuboctahedra. All Nb(1)-Nb(1) bond lengths are 3.00 Å.