RICICLE: A FORTRAN program to refine unit cell parameters of incommensurate structures

1993 ◽  
Vol 8 (3) ◽  
pp. 168-172 ◽  
Author(s):  
R. I. Smith
Keyword(s):  
Least Squares ◽  
Powder Diffraction ◽  
Fortran Program ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Full Matrix ◽  
Cell Parameters ◽  
Incommensurate Structures ◽  
Diffraction Patterns ◽  
Modulation Vector

A FORTRAN 77 program to perform full matrix least-squares refinement of unit cell parameters from powder diffraction patterns showing incommensurate supercell reflections is described. The code is completely general, being applicable to any crystal system, and can refine all three unit cell edges and angles and, in the presence of an incommensurate supercell, can refine the components of the modulation vector along all three reciprocal axes. Estimated standard deviations on all the refined parameters are calculated analytically.

X-ray powder diffraction data of anilinium trimolybdate tetrahydrate and anilinium trimolybdate dihydrate

1999 ◽  
Vol 14 (4) ◽  
pp. 280-283 ◽  
Author(s):  
A. Rafalska-Łasocha ◽  
W. Łasocha ◽  
M. Michalec
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Room Temperature ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns

The X-ray powder diffraction patterns of anilinium trimolybdate tetrahydrate, (C6H5NH3)2Mo3O10·4H2O, and anilinium trimolybdate dihyhydrate, (C6H5NH3)2Mo3O10·2H2O, have been measured in room temperature. The unit cell parameters were refined to a=11.0670(7) Å, b=7.6116(8) Å, c=25.554(3) Å, space group Pnma(62) and a=17.560(2) Å, b=7.5621(6) Å, c=16.284(2) Å, β=108.54(1)°, space group P21(4) or P21/m(11) for orthorhombic anilinium trimolybdate tetrahydrate and monoclinic anilinium trimolybdate dihydrate, respectively.

Systematic crystallographic refinement of triclinic unit cells

1998 ◽  
Vol 13 (1) ◽  
pp. 22-31
Author(s):  
Ludo K. Frevel
Keyword(s):  
Powder Diffraction ◽  
Unit Cell ◽  
Simultaneous Equations ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Triclinic Phase ◽  
Unit Cells ◽  
Diffraction Patterns ◽  
Limits Of Error

Combining the exhaustive indexing of triclinic powder diffraction patterns with a crystallographic determination of unit cell parameters from pinacoid and prism reflections yields unit cell parameters with realistic limits of error. Additionally a referee method has been developed by which the six reciprocal cell parameters of a triclinic phase are determined by solving an exhaustive set of linear simultaneous equations in six unknowns.

X-ray powder diffraction pattern for lactitol and lactitol monohydrate

1994 ◽  
Vol 9 (3) ◽  
pp. 213-216 ◽  
Author(s):  
J. Valkonen ◽  
P. Perkkalainen ◽  
I. Pitkänen ◽  
H. Rautiainen
Keyword(s):  
Powder Diffraction ◽  
Least Squares Method ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Cell Dimensions ◽  
Diffraction Patterns ◽  
Unit Cell Dimensions

Diffraction patterns were recorded, and unit cell dimensions refined by the least-squares method, for lactitol and lactitol monohydrate. Refined unit cell parameters for lactitol are: a =7.622(1) Å, b = 10.764(2) Å, c = 9.375(1) Å, β= 108.25(1)° in space group P21, and those for lactitol monohydrate a =7.844(1) Å, b = 12.673(2) Å, c = 15.942(2) Å in space group P212121.

X-ray powder diffraction data for five lanthanoid chromates [Ln2(CrO4)3(H2O)5]·2H2O (Ln=La,Pr,Nd,Sm,Eu)

1994 ◽  
Vol 9 (2) ◽  
pp. 98-104
Author(s):  
Jaakko Leppä-aho ◽  
Jussi Valkonen
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns

X-ray powder diffraction data are reported for a series of isomorphous compounds of [Ln2(CrO4)3(H2O)5]·2H2O, where Ln=La, Pr, Nd, Sm, or Eu. The compounds crystallize in monoclinic space group P21/c (No: 14) with Z=4. Refined unit cell parameters and indexed powder diffraction patterns are given.

Crystal data for benzofuroin

1983 ◽  
Vol 16 (1) ◽  
pp. 140-140
Author(s):  
O. Durruthy ◽  
F. Fajardo ◽  
R. Pomes
Keyword(s):  
Powder Diffraction ◽  
Unit Cell ◽  
Crystal Data ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns

Benzofuroin crystal data were obtained from X-ray powder diffraction patterns. Benzofuroin, C12H10O3, is monoclinic P21/c, with unit-cell parameters a = 10.672 (3), b = 16.521 (4), c = 5.586 (1) Å and γ = 110.45 (3)°, V= 922.8 (10) Å3, Z = 4, Dx = 1.45 Mgm−3.

Exhaustive indexing of triclinic powder diffraction patterns with known unit cell parameters

1994 ◽  
Vol 9 (2) ◽  
pp. 87-92 ◽  
Author(s):  
Ludo K. Frevel
Keyword(s):  
Powder Diffraction ◽  
Interplanar Spacing ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Triclinic Phase ◽  
Diffraction Patterns ◽  
Cell Volumes ◽  
Novel Algorithm

A novel algorithm has been developed for obtaining directly the applicable indices hkl for any interplanar spacing, dobs±Δdobs, of a triclinic phase with known unit cell parameters. This method is particularly useful for indexing back reflections for triclinic phases with unit cell volumes greater than 500 Å3.

X-ray powder diffraction data for two new N-substituted 3,4-dihydrospiro-2(1H) quinolines

1999 ◽  
Vol 14 (4) ◽  
pp. 249-252 ◽  
Author(s):  
J. A. Henao ◽  
A. Palma ◽  
V. V. Kouznetsov ◽  
J. M. Delgado
Keyword(s):  
Key Words ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns

The X-ray powder diffraction patterns for two N-substituted tetrahydroquinolines are reported. N-(α-Chloroacetyl)-6-methoxy-3,4-dihydro-4-methylspiro[cyclohexane-1′,2(1H)quinoline], C18H24ClNO2, and N-(α-chloroacetyl)-6-chloro-3,4-dihydro-4-methylspiro[cyclohexane-1′,2(1H)-quinoline], C17H21Cl2NO are monoclinic, with refined unit cell parameters a=1.4471(3), b=0.9600(4), c=1.1948(3) nm, β=93.21(2)°, V=1.6573(6) nm3, Z=4, Dx=1.29 gcm−3, and a=1.4487(3), b=0.9878(2), c=1.1390(2) nm, β=91.66(2)°, V=1.6294(4) nm3, Z=4, and Dx=1.32 gcm−3, respectively, with space group P21/n (No. 14).Key words: powder diffraction data, spirotetrahydroquinolines.

Improved powder diffraction data for two cholesterol derivatives

2003 ◽  
Vol 18 (4) ◽  
pp. 306-308 ◽  
Author(s):  
Manuela Ramos Silva ◽  
Ana Matos Beja ◽  
José António Paixa˜o ◽  
Abílio J. F. N. Sobral ◽  
Ana S. M. Ressurreição ◽  
...  
Keyword(s):  
Single Crystal ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns ◽  
Atomic Parameters

New X-ray powder diffraction patterns for two cholesterol derivatives, cholest-4-ene-3,6-dione and cholest-4-en-3-one are reported in the range 0<2θ<115°. Both compounds crystallize in similar monoclinic cells in space-group P21, with unit cell parameters a=10.481(3) Å, b=8.0354(8) Å, c=14.677(3) Å, β=105.265(7)°, V=1192.5(4) Å3 for C27H42O2, and a=10.703(2) Å, b=7.8750(6) Å, c=14.660(3) Å, β=105.205(14)°, V=1192.4(4) Å3 for C27H44O. The patterns, confirmed by single-crystal studies, do not match the PDF 17-1144 and PDF 10-649. A fitting of the overall parameters was performed with Fullprof using the atomic parameters obtained from single-crystal studies.

New X-ray powder diffraction data for thallium pentaborates Tl[B5O6(OH)4]·2H2O and TlB5O8

1999 ◽  
Vol 14 (3) ◽  
pp. 237-239 ◽  
Author(s):  
M. Touboul ◽  
N. Penin ◽  
L. Seguin
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Figures Of Merit ◽  
Diffraction Patterns

Precise X-ray powder diffraction patterns of hydrated and anhydrous thallium pentaborates have been collected on a D5000 diffractometer with a primary monochromated beam (λ Cu Kα1=1.5406 Å). Refinement of indexed reflections led to the following unit cell parameters: a=11.279(1)Å, b=7.1507(6)Å, c=13.953(1)Å, β=94.164(7)° in the P21/c space group with Z=4, Dx=2.713 gcm−3, Dm=2.6 gcm−3 for Tl[B5O6(OH)4]·2H2O and a=7.5698(5)Å, b=11.9509(6)Å, c=14.759(1)Å in the Pbca space group with Z=8, Dx=3.844 gcm−3, Dm=3.6 gcm−3 for TlB5O8. Very good Smith and Snyder figures of merit have been obtained: F30=139.7 (0.0043, 50) for Tl[B5O6(OH)4]·2H2O and F30=139.3 (0.0054, 40) for TlB5O8.

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