data_global
_chemical_name_mineral 'Eudidymite'
loop_
_publ_author_name
'Gatta G D'
'Rotiroti N'
'McIntyre G J'
'Guastoni A'
'Nestola F'
_journal_name_full 'American Mineralogist'
_journal_volume 93 
_journal_year 2008
_journal_page_first 1158
_journal_page_last 1165
_publ_section_title
;
 New insights into the crystal chemistry of epididymite and eudidymite
 from Malosa, Malawi: A single-crystal neutron diffraction study
;
_database_code_amcsd 0004615
_chemical_compound_source 'Malosa, Malawi'
_chemical_formula_sum 'Na2 Be2 Si6 O16 H2'
_cell_length_a 12.6188
_cell_length_b 7.3781
_cell_length_c 13.9940
_cell_angle_alpha 90
_cell_angle_beta 103.762
_cell_angle_gamma 90
_cell_volume 1265.477
_exptl_crystal_density_diffrn      2.575
_symmetry_space_group_name_H-M 'C 1 2/c 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  'x,-y,1/2+z'
  '1/2+x,1/2-y,1/2+z'
  '-x,y,1/2-z'
  '1/2-x,1/2+y,1/2-z'
  '-x,-y,-z'
  '1/2-x,1/2-y,-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
Na   0.02899   0.34078   0.92853   1.00000   0.02600
Be   0.16817   0.32317   0.49710   1.00000   0.00670
Si1   0.20415   0.01965   0.64127   1.00000   0.00450
Si2   0.25166   0.10250   0.86648   1.00000   0.00500
Si3   0.02964   0.09397   0.36195   1.00000   0.00500
O1   0.07277   0.03247   0.62614   1.00000   0.01080
O2   0.24036   0.18030   0.11540   1.00000   0.01270
O3   0.24045   0.16471   0.57054   1.00000   0.00730
O4   0.23677   0.43859   0.24484   1.00000   0.01220
O5   0.15480   0.49864   0.05623   1.00000   0.00870
O6   0.12854   0.05189   0.87541   1.00000   0.01030
O7   0.00000   0.17321   0.25000   1.00000   0.01090
O8   0.05237   0.25694   0.43729   1.00000   0.00920
H1   0.08400   0.46450   0.74490   0.50000   0.05900
H2  -0.02270   0.54190   0.74860   0.50000   0.05400
OW   0.01209   0.43098   0.74466   0.50000 ?
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
Na 0.02560 0.02990 0.02410 -0.00890 0.00890 -0.01020
Be 0.00680 0.00580 0.00730 -0.00050 0.00150 0.00050
Si1 0.00680 0.00260 0.00470 0.00120 0.00240 -0.00040
Si2 0.00580 0.00370 0.00510 0.00100 0.00050 -0.00100
Si3 0.00420 0.00620 0.00440 -0.00060 0.00070 -0.00110
O1 0.00730 0.01080 0.01480 0.00190 0.00380 -0.00220
O2 0.01910 0.00380 0.01590 -0.00040 0.00550 -0.00230
O3 0.00870 0.00630 0.00760 0.00300 0.00340 0.00040
O4 0.01490 0.01670 0.00510 -0.00220 0.00280 -0.00090
O5 0.00830 0.00790 0.00880 0.00320 0.00010 -0.00110
O6 0.00800 0.00920 0.01380 0.00100 0.00300 -0.00290
O7 0.01690 0.00890 0.00640 0.00000 0.00160 0.00000
O8 0.00730 0.01080 0.00880 -0.00390 0.00040 -0.00030
H1 0.04200 0.08300 0.05000 -0.00100 0.00700 -0.01800
H2 0.06400 0.04300 0.05500 0.00400 0.01600 0.02000