The compound described by BaAl2Ge2 crystallizes in the orthorhombic Pnma space group. Ba(1) is bonded in a 16-coordinate geometry to four equivalent Al(2), five equivalent Al(1), three equivalent Ge(1), and four equivalent Ge(2) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to five equivalent Ba(1), one Ge(2), and three equivalent Ge(1) atoms to form distorted AlBa5Ge4 tetrahedra that share corners with eight equivalent Al(2)Ba4Ge4 tetrahedra, corners with eight equivalent Al(1)Ba5Ge4 tetrahedra, edges with two equivalent Al(1)Ba5Ge4 tetrahedra, faces with four equivalent Al(1)Ba5Ge4 tetrahedra, and faces with six equivalent Al(2)Ba4Ge4 tetrahedra. In the second Al site, Al(2) is bonded to four equivalent Ba(1), one Ge(1), and three equivalent Ge(2) atoms to form distorted AlBa4Ge4 tetrahedra that share corners with six equivalent Al(2)Ba4Ge4 tetrahedra, corners with eight equivalent Al(1)Ba5Ge4 tetrahedra, edges with two equivalent Al(2)Ba4Ge4 tetrahedra, faces with two equivalent Al(2)Ba4Ge4 tetrahedra, and faces with six equivalent Al(1)Ba5Ge4 tetrahedra. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 7-coordinate geometry to three equivalent Ba(1), one Al(2), and three equivalent Al(1) atoms. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to four equivalent Ba(1), one Al(1), and three equivalent Al(2) atoms. is represented by the CIF file [CIF]
data_Ba(AlGe)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.281
_cell_length_b   10.264
_cell_length_c   11.005
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   483.541
_cell_formula_units_Z   4
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
  Ba  Ba0  1  0.750  0.252  0.325  1.0
  Ba  Ba1  1  0.750  0.752  0.175  1.0
  Ba  Ba2  1  0.250  0.748  0.675  1.0
  Ba  Ba3  1  0.250  0.248  0.825  1.0
  Al  Al4  1  0.250  0.042  0.117  1.0
  Al  Al5  1  0.750  0.900  0.453  1.0
  Al  Al6  1  0.750  0.458  0.617  1.0
  Al  Al7  1  0.750  0.400  0.047  1.0
  Al  Al8  1  0.250  0.600  0.953  1.0
  Al  Al9  1  0.250  0.542  0.383  1.0
  Al  Al10  1  0.750  0.958  0.883  1.0
  Al  Al11  1  0.250  0.100  0.547  1.0
  Ge  Ge12  1  0.250  0.353  0.540  1.0
  Ge  Ge13  1  0.750  0.647  0.460  1.0
  Ge  Ge14  1  0.250  0.476  0.157  1.0
  Ge  Ge15  1  0.750  0.524  0.843  1.0
  Ge  Ge16  1  0.750  0.024  0.657  1.0
  Ge  Ge17  1  0.250  0.853  0.960  1.0
  Ge  Ge18  1  0.250  0.976  0.343  1.0
  Ge  Ge19  1  0.750  0.147  0.040  1.0
[/CIF]
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The compound described by BaAl2Ge2 crystallizes in the orthorhombic Pnma space group. Ba(1) is bonded in a 16-coordinate geometry to four equivalent Al(2), five equivalent Al(1), three equivalent Ge(1), and four equivalent Ge(2) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to five equivalent Ba(1), one Ge(2), and three equivalent Ge(1) atoms to form distorted AlBa5Ge4 tetrahedra that share corners with eight equivalent Al(2)Ba4Ge4 tetrahedra, corners with eight equivalent Al(1)Ba5Ge4 tetrahedra, edges with two equivalent Al(1)Ba5Ge4 tetrahedra, faces with four equivalent Al(1)Ba5Ge4 tetrahedra, and faces with six equivalent Al(2)Ba4Ge4 tetrahedra. In the second Al site, Al(2) is bonded to four equivalent Ba(1), one Ge(1), and three equivalent Ge(2) atoms to form distorted AlBa4Ge4 tetrahedra that share corners with six equivalent Al(2)Ba4Ge4 tetrahedra, corners with eight equivalent Al(1)Ba5Ge4 tetrahedra, edges with two equivalent Al(2)Ba4Ge4 tetrahedra, faces with two equivalent Al(2)Ba4Ge4 tetrahedra, and faces with six equivalent Al(1)Ba5Ge4 tetrahedra. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 7-coordinate geometry to three equivalent Ba(1), one Al(2), and three equivalent Al(1) atoms. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to four equivalent Ba(1), one Al(1), and three equivalent Al(2) atoms. is represented by the CIF file [CIF]
data_Ba(AlGe)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.281
_cell_length_b   10.264
_cell_length_c   11.005
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   483.541
_cell_formula_units_Z   4
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
  Ba  Ba0  1  0.750  0.252  0.325  1.0
  Ba  Ba1  1  0.750  0.752  0.175  1.0
  Ba  Ba2  1  0.250  0.748  0.675  1.0
  Ba  Ba3  1  0.250  0.248  0.825  1.0
  Al  Al4  1  0.250  0.042  0.117  1.0
  Al  Al5  1  0.750  0.900  0.453  1.0
  Al  Al6  1  0.750  0.458  0.617  1.0
  Al  Al7  1  0.750  0.400  0.047  1.0
  Al  Al8  1  0.250  0.600  0.953  1.0
  Al  Al9  1  0.250  0.542  0.383  1.0
  Al  Al10  1  0.750  0.958  0.883  1.0
  Al  Al11  1  0.250  0.100  0.547  1.0
  Ge  Ge12  1  0.250  0.353  0.540  1.0
  Ge  Ge13  1  0.750  0.647  0.460  1.0
  Ge  Ge14  1  0.250  0.476  0.157  1.0
  Ge  Ge15  1  0.750  0.524  0.843  1.0
  Ge  Ge16  1  0.750  0.024  0.657  1.0
  Ge  Ge17  1  0.250  0.853  0.960  1.0
  Ge  Ge18  1  0.250  0.976  0.343  1.0
  Ge  Ge19  1  0.750  0.147  0.040  1.0
[/CIF]
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