data_1008952
_chemical_name_systematic          'Niobium selenide (1/3)'
_chemical_formula_structural       'Nb Se3'
_chemical_formula_sum              'Nb Se3'
_publ_section_title
;
Determination of the structural distortions corresponding to the q1-
and q2- -type modulations in niobium triselenide Nb Se3
;
loop_
_publ_author_name
  'van=Smaalen, S'
  'de=Boer, J L'
  'Meetsma, A'
  'Graafsma, H'
  'Sheu, H-S'
  'Darovskikh, A'
  'Coppens, P'
  'Levy, F'
_journal_name_full
;
Physical Review, Serie 3. B - Condensed Matter (18,1978-)
;
_journal_coden_ASTM                PRBMDO
_journal_volume                    45
_journal_year                      1992
_journal_page_first                3103
_journal_page_last                 3106
_journal_issue                     6
_cell_length_a                     9.974(1)
_cell_length_b                     3.476(2)
_cell_length_c                     15.592(2)
_cell_angle_alpha                  90
_cell_angle_beta                   109.4(1)
_cell_angle_gamma                  90
_cell_volume                       509.9
_cell_formula_units_Z              6
_symmetry_space_group_name_H-M     'P 1 21/m 1'
_symmetry_Int_Tables_number        11
_symmetry_cell_setting             monoclinic
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  '-x,1/2+y,-z'
  '-x,-y,-z'
  'x,1/2-y,z'
loop_
_atom_type_symbol
_atom_type_oxidation_number
  Nb0    0.000
  Se0    0.000
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_symmetry_multiplicity
_atom_site_Wyckoff_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_attached_hydrogens
_atom_site_calc_flag
  Nb1   Nb0    2 e 0.3858(1) 0.25 0.7326(1) 1.  0 d
  Nb2   Nb0    2 e 0.2615(1) 0.75 -0.0552(1) 1.  0 d
  Nb3   Nb0    2 e 0.3780(1) 0.25 0.0837(1) 1.  0 d
  Se1   Se0    2 e 0.2539(2) 0.75 0.8132(1) 1.  0 d
  Se2   Se0    2 e 0.4601(2) 0.75 0.6267(1) 1.  0 d
  Se3   Se0    2 e 0.5212(2) 0.75 0.7174(1) 1.  0 d
  Se4   Se0    2 e 0.1260(2) 0.25 -0.0393(1) 1.  0 d
  Se5   Se0    2 e 0.2273(2) 0.25 0.0491(1) 1.  0 d
  Se6   Se0    2 e 0.3881(2) 0.25 0.8603(1) 1.  0 d
  Se7   Se0    2 e 0.2534(2) 0.75 0.1716(1) 1.  0 d
  Se8   Se0    2 e 0.4246(2) 0.75 -0.0195(1) 1.  0 d
  Se9   Se0    2 e 0.4099(2) 0.75 0.1658(1) 1.  0 d
_refine_ls_R_factor_all            0.073