data_global
_chemical_name_mineral 'Keiviite-(Yb)'
loop_
_publ_author_name
'Yakubovich O V'
'Simonov M A'
'Voloshin A V'
'Pakhomovsky Y A'
_journal_name_full 'Soviet Physics Doklady'
_journal_volume 31 
_journal_year 1986
_journal_page_first 930
_journal_page_last 932
_publ_section_title
;
 Crystal structure of keivite Yb2[Si2O7]
;
_database_code_amcsd 0015614
_chemical_compound_source 'Kola Peninsula, Russia'
_chemical_formula_sum '(Yb1.42 Lu.22 Er.16 Tm.08 Y.06 Dy.04 Ho.02) Si2 O7'
_cell_length_a 4.715
_cell_length_b 8.870
_cell_length_c 6.805
_cell_angle_alpha 90
_cell_angle_beta 102.01
_cell_angle_gamma 90
_cell_volume 278.370
_exptl_crystal_density_diffrn      6.058
_symmetry_space_group_name_H-M 'A 1 2/m 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,1/2+y,1/2+z'
  '-x,y,-z'
  '-x,1/2+y,1/2-z'
  'x,-y,z'
  'x,1/2-y,1/2+z'
  '-x,-y,-z'
  '-x,1/2-y,1/2-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_U_iso_or_equiv
Yb   0.00000   0.80653   0.50000   0.71000   0.00671
Lu   0.00000   0.80653   0.50000   0.11000   0.00671
Er   0.00000   0.80653   0.50000   0.08000   0.00671
Tm   0.00000   0.80653   0.50000   0.04000   0.00671
Y   0.00000   0.80653   0.50000   0.03000   0.00671
Dy   0.00000   0.80653   0.50000   0.02000   0.00671
Ho   0.00000   0.80653   0.50000   0.01000   0.00671
Si   0.41270   0.50000   0.71880   1.00000   0.00963
O1   0.50000   0.50000   0.50000   1.00000   0.01900
O2   0.71600   0.50000   0.88100   1.00000   0.01140
O3   0.22000   0.65060   0.73500   1.00000   0.01393
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Yb 0.00811 0.00772 0.00773 0.00000 0.00165 0.00000
Lu 0.00811 0.00772 0.00773 0.00000 0.00165 0.00000
Er 0.00811 0.00772 0.00773 0.00000 0.00165 0.00000
Tm 0.00811 0.00772 0.00773 0.00000 0.00165 0.00000
Y 0.00811 0.00772 0.00773 0.00000 0.00165 0.00000
Dy 0.00811 0.00772 0.00773 0.00000 0.00165 0.00000
Ho 0.00811 0.00772 0.00773 0.00000 0.00165 0.00000
Si 0.00849 0.00925 0.01140 0.00000 0.00481 0.00000
O1 0.02026 0.02660 0.00760 0.00000 0.00380 0.00000
O2 0.01266 0.00886 0.01520 0.00000 0.00507 0.00000
O3 0.01647 0.01013 0.01773 0.00380 0.00760 0.00127