Dear Mrs. Chrysochoou,
the cif-file below was created from the AMCSD (American Mineralogist Crystal
Structure Database) reference database by Match!, Crystal Impact's software
for phase identification from powder diffraction data. The I/Ic value
calculated by Match! is 20.5
Best wishes
Holger
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### Entry exported from Match! User Database
###
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### Data published by:
###
###
###
### AMCSD (American Mineralogist Crystal Structure
Database)</A>
### R.T. Downs, M. Hall-Wallace, "The American Mineralogist
Crystal Structure Database", American Mineralogist <B>88</B>, 247-250
(2003).
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data_amcsd
_citation_journal_full 'American Mineralogist'
_citation_journal_volume '87'
_citation_page_first '966'
_citation_page_last '975'
_citation_year '2002'
_citation_title 'The nature of disorder in montmorillonite by simulation of
X-ray powder patternsNote: Structural simulation model'
loop_
_publ_author_name
'Viani A'
'Gualtieri A'
'Artioli G'
_chemical_formula_sum 'Al2 Si4 O12 Ca.5'
_chemical_name_mineral 'Montmorillonite'
_chemical_name_common 'Montmorillonite'
_symmetry_space_group_name_H-M 'P 1'
_space_group_IT_number 1
_space_group_crystal_system 'triclinic'
loop_
_symmetry_equiv_pos_as_xyz
'x, y, z'
_cell_length_a 5.1800
_cell_length_b 8.9800
_cell_length_c 15.0000
_cell_angle_alpha 90.000
_cell_angle_beta 90.000
_cell_angle_gamma 90.000
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_B_iso_or_equiv
al 0.875 0.333 0.221 1.00000 1.000
al 0.875 0.667 0.221 1.00000 1.000
al 0.375 0.833 0.221 1.00000 1.000
al 0.375 0.167 0.221 1.00000 1.000
si 0.559 0.329 0.043 1.00000 1.000
si 0.559 0.671 0.043 1.00000 1.000
si 0.692 0.829 0.400 1.00000 1.000
si 0.692 0.171 0.400 1.00000 1.000
si 0.059 0.829 0.043 1.00000 1.000
si 0.059 0.171 0.043 1.00000 1.000
si 0.192 0.329 0.400 1.00000 1.000
si 0.192 0.671 0.400 1.00000 1.000
o 0.513 0.500 0.010 1.00000 1.000
o 0.828 0.728 0.000 1.00000 1.000
o 0.828 0.272 0.000 1.00000 1.000
o 0.495 0.000 0.152 1.00000 1.000
o 0.568 0.691 0.149 1.00000 1.000
o 0.572 0.309 0.149 1.00000 1.000
o 0.737 0.000 0.433 1.00000 1.000
o 0.423 0.228 0.443 1.00000 1.000
o 0.423 0.772 0.443 1.00000 1.000
o 0.755 0.500 0.291 1.00000 1.000
o 0.682 0.191 0.294 1.00000 1.000
o 0.678 0.809 0.294 1.00000 1.000
o 0.013 0.000 0.010 1.00000 1.000
o 0.328 0.228 0.000 1.00000 1.000
o 0.328 0.772 0.000 1.00000 1.000
o 0.995 0.500 0.152 1.00000 1.000
o 0.068 0.191 0.149 1.00000 1.000
o 0.072 0.809 0.149 1.00000 1.000
o 0.237 0.500 0.433 1.00000 1.000
o 0.923 0.728 0.443 1.00000 1.000
o 0.923 0.272 0.443 1.00000 1.000
o 0.255 0.000 0.291 1.00000 1.000
o 0.182 0.691 0.294 1.00000 1.000
o 0.178 0.309 0.294 1.00000 1.000
ca 0.189 0.000 0.722 0.50000 1.000
ca 0.689 0.500 0.722 0.50000 1.000
_cell_measurement_wavelength 1.541874
_cell_measurement_radiation 'x-rays'
_exptl_crystal_density_diffrn 1.800000
loop_
_pd_peak_d_spacing
_pd_peak_calc_intensity_net
15.000000 1000.00
7.500000 4.72
5.000000 29.57
4.490000 23.21
4.487008 2.06
4.301428 25.91
4.298797 37.33
3.852407 6.90
3.850517 36.31
3.750000 9.59
3.340711 0.80
3.339478 13.25
3.000000 11.02
2.878201 0.21
2.877412 12.58
2.591727 0.26
2.590000 0.54
2.553885 16.89
2.552233 7.27
2.500000 0.86
2.494440 6.44
2.493927 1.55
2.449592 21.03
2.448134 9.46
2.300980 8.90
2.299771 7.48
2.245000 1.16
2.243504 0.24
2.220271 0.11
2.218823 1.37
2.184245 0.18
2.183900 1.92
2.150714 0.39
2.149399 0.27
2.142857 4.33
2.132075 7.04
2.131113 4.22
2.048029 0.55
2.046893 1.37
1.961214 4.61
1.960465 1.59
1.933904 0.02
1.933665 1.57
1.926204 0.75
1.925259 5.23
1.875000 1.44
1.799321 1.80
1.798743 0.94
1.797437 0.27
1.796669 2.46
1.730199 0.30
1.730027 0.98
1.696899 0.17
1.696414 0.12
1.695607 1.30
1.686144 3.60
1.685668 0.17
1.684876 1.83
1.670355 1.66
1.669739 0.58
1.666667 0.06
1.655066 2.96
1.654616 2.74
1.653867 1.04
1.651477 4.08
1.651030 2.19
1.606881 0.62
1.606469 1.45
1.605784 0.66
1.562494 0.08
1.562368 0.65
1.550081 2.64
1.549588 0.59
1.545985 1.61
1.545618 0.93
1.545008 0.24
1.519133 3.26
1.518786 2.54
1.500000 0.67
1.496667 2.87
1.495669 5.42
1.489272 1.88
1.488289 3.70
1.476994 0.08
1.476674 0.61
1.476142 2.35
1.467728 0.24
1.466787 0.65
1.439101 0.00
1.438706 3.00
1.433810 0.33
1.432932 0.11
##############################################################################
### Comments
###
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### Diffraction pattern calculated by Match!.
### I/Icor calculated by Match!.
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----- Original Message -----
From: "Chrysochoou, Maria" <[EMAIL PROTECTED]>
To: <rietveld_l@ill.fr>
Sent: Saturday, March 15, 2008 4:06 PM
Subject: Montmorillonite cif
Hi,
does anyone have a freely available structure file for montmorillonite
(any hydration state)? Also, what is a reasonable Reference Intensity
Ratio for it? The only ICSD entry has an RIR of over 23, so does
vermiculite. Why is that so high?
Thank you,
Maria Chrysochoou
