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Powder study of hydro­chloro­thia­zide form II

aDepartment of Pharmaceutical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, Scotland, and bISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, England
*Correspondence e-mail: alastair.florence@strath.ac.uk

(Received 14 July 2005; accepted 25 July 2005; online 6 August 2005)

The crystal structure of hydro­chloro­thia­zide form II, C7H8ClN3O4S2, was solved by simulated annealing from laboratory X-ray powder diffraction data collected at room temperature to 1.76 Å resolution. Subsequent Rietveld refinement yielded an Rwp of 0.0376 to 1.49 Å resolution. The molecules crystallize in the space group P21/c with one molecule in the asymmetric unit. The structure is stabilized by three N—H⋯N and one N—H⋯O hydrogen-bonded intermolecular interaction.

Comment

Hydro­chloro­thia­zide (HCT) is a thia­zide diuretic which is known to crystallize in at least one non-solvated form (Dupont & Dideberg, 1972[Dupont, L. & Dideberg, O. (1972). Acta Cryst. B28, 2340-2347. (In French.)]). A polycrystalline sample of a second polymorph of HCT, form II, (I)[link], was produced using a modified precipitation technique in which an acetone solution of HCT was added to distilled water containing hydroxy­propyl­methyl­cellulose (grade E5LV, Dow Chemicals, USA) under

[Scheme 1]
agitation. The resulting precipitate was immediately isolated from solution by membrane filtration. The sample was identified as a new form using multisample X-ray powder diffraction analysis (Florence et al., 2003[Florence, A. J., Baumgartner, B., Weston, C., Shankland, N., Kennedy, A. R., Shankland, K. & David, W. I. F. (2003). J. Pharm. Sci. 92, 1930-1938.]). The sample was found to contain a trace amount of HCT form I (Dupont & Dideberg, 1972[Dupont, L. & Dideberg, O. (1972). Acta Cryst. B28, 2340-2347. (In French.)]).

The crystal structure of (I)[link] was solved by simulated annealing using laboratory X-ray powder diffraction data (Fig. 1[link]). The compound crystallizes in space group P21/c with one mol­ecule in the asymmetric unit (Fig. 2[link]). In (I)[link], the N2/S1/C1/C2/N1/C3 ring in HCT displays a non-planar conformation, atoms N2 and C3 having the largest deviations [0.458 (1) and −0.266 (1) Å, respectively] from the least-squares plane through the aromatic ring. The sulfonamide side chain adopts a torsion angle N3—S2—C5—C6 = 59.53 (19)°, such that O1 eclipses H4, and atoms O4 and N3 are staggered with respect to Cl1. In HCT form I (Dupont & Dideberg, 1972[Dupont, L. & Dideberg, O. (1972). Acta Cryst. B28, 2340-2347. (In French.)]), this group is rotated by approximately 120° compared with (I)[link], such that the amine group lies on the opposite side of the benzothia­diazine ring system.

The crystal structure is stabilized by a series of inter­molecular contacts including three N—H⋯N hydrogen bonds (contacts 1–3, Fig. 3[link]), one N—H⋯O hydrogen bond (contact 4) and a C—H⋯O contact (contact 5). Contact 1 forms a centrosymmetric R22(8) dimer motif (Fig. 4[link], A), whilst contacts 3 and 4 produce a larger R44(24) motif (Fig. 4[link], B) connecting four mol­ecules of HCT. Contacts 2 and 3 also combine to produce an R42(20) ring motif (Fig. 4[link], C).

[Figure 1]
Figure 1
Final observed (points), calculated (line) and difference [(yobsycalc)/σ(yobs)] profiles for the Rietveld refinement of the title compound.
[Figure 2]
Figure 2
The molecular structure with the atom-numbering scheme. Isotropic displacement spheres are shown at the 50% probability level.
[Figure 3]
Figure 3
Packing diagram illustrating inter­molecular contacts (dashed lines) in the structure of (I)[link]. Unique contacts are labelled as follows: 1: N2⋯O3 = 2.905 (4) Å, O3 in the mol­ecule at (−x, 1 − y, −z); 2: N1⋯O1 = 2.920 (3) Å, O1 in the mol­ecule at (x,1/2 − y,-[{1\over 2}] + z); 3: N3⋯O1 = 3.121 (3) Å, O1 in the mol­ecule at (1 − x, [{1\over 2}] + y, [{1\over 2}]z); 4: N3⋯N2 = 3.214 (2) Å, N2 in the mol­ecule at (1 + x, [{1\over 2}]y, [{1\over 2}] + z); 5: C3⋯O2 = 3.416 (3) Å, O2 in the mol­ecule at (−x, [{1\over 2}] + y, −[{1\over 2}]z). Contacts calculated and illustrated using PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]; program version 280604).
[Figure 4]
Figure 4
(Top) The R22(8) (labelled A) and R44(24) (labelled B) motifs within the structure of (I)[link]. (Bottom left) The R42(20) motif, shown with atoms not involved in the motif omitted for clarity.

Experimental

A sample of (I), obtained using the method described in the Comment, was lightly ground in a mortar, loaded into a 0.7 mm borosilicate glass capillary and mounted on the diffractometer. Data were collected from a sample in a rotating 0.7 mm borosilicate glass capillary using a variable count time scheme (Shankland et al., 1997[Shankland, K., David, W. I. F. & Sivia, D. S. (1997). J. Mater. Chem. 7, 569-572.]; Hill & Madsen, 2002[Hill, R. J. & Madsen, I. C. (2002). Structure Determination from Powder Diffraction Data, edited by W. I. F. David, K. Shankland, L. B. McCusker & Ch. Baerlocher, pp.114-116. Oxford University Press.]).

Crystal data
  • C7H8ClN3O4S2

  • Mr = 297.75

  • Monoclinic, P 21 /c

  • a = 9.4884 (5) Å

  • b = 8.3334 (4) Å

  • c = 15.1309 (7) Å

  • β = 113.2087 (19)°

  • V = 1099.59 (9) Å3

  • Z = 4

  • Dx = 1.799 Mg m−3

  • Cu Kα1 radiation

  • μ = 6.75 mm−1

  • T = 298 K

  • Specimen shape: cylinder

  • 12 × 0.7 mm

  • Specimen prepared at 298 K

  • Particle morphology: visual estimate, prisms, white

Data collection
  • Bruker AXS D8 Advance diffractometer

  • Specimen mounting: 0.7 mm borosilicate capillary

  • Specimen mounted in transmission mode

  • Scan method: step

  • Absorption correction: none

  • 2θmin = 5.0, 2θmax = 65.0°

  • Increment in 2θ = 0.017°

Refinement
  • Refinement on Inet

  • Rp = 0.033

  • Rwp = 0.038

  • Rexp = 0.023

  • RB = 0.013

  • S = 1.64

  • Excluded region(s): 62.1 to 65.0% due to poor signal-to-noise

  • Profile function: fundamental parameters with axial divergence correction

  • 355 reflections

  • 92 parameters

  • Only H-atom coordinates refined

  • Weighting scheme based on measured s.u.'s 1/σ(Yobs)2

  • (Δ/σ)max = 0.005

  • Preferred orientation correction: a spherical harmonics-based preferred orientation correction was applied with TOPAS during the Rietveld refinement

Table 1
Selected geometric parameters (Å, °)[link]

Cl1—C6 1.730 (2)
S1—O2 1.425 (3)
S1—O3 1.426 (2)
S1—N2 1.6438 (16)
S1—C1 1.7650 (17)
S2—O1 1.428 (2)
S2—O4 1.429 (3)
S2—N3 1.633 (2)
S2—C5 1.772 (2)
N1—C2 1.358 (2)
N1—C3 1.473 (2)
N2—C3 1.441 (2)
O2—S1—O3 119.4 (2)
O2—S1—N2 110.42 (13)
O2—S1—C1 108.92 (17)
O3—S1—N2 106.39 (18)
O3—S1—C1 109.25 (10)
N2—S1—C1 100.90 (10)
O1—S2—O4 122.35 (19)
O1—S2—N3 106.27 (14)
O1—S2—C5 105.68 (13)
O4—S2—N3 107.67 (14)
O4—S2—C5 108.82 (13)
N3—S2—C5 104.75 (10)
C2—N1—C3 123.27 (16)
S1—N2—C3 113.58 (11)
S1—C1—C2 119.80 (11)
S1—C1—C4 119.55 (11)
N1—C2—C1 121.84 (13)
N1—C2—C7 120.34 (13)
N1—C3—N2 108.10 (11)
S2—C5—C4 117.40 (12)
S2—C5—C6 124.83 (13)
Cl1—C6—C5 121.28 (16)
Cl1—C6—C7 117.16 (14)

Table 2
Hydrogen-bond geometry (Å, °)[link]

D—H⋯A D—H H⋯A DA D—H⋯A
N2—H5⋯O3i 0.95 (1) 2.03 (1) 2.905 (4) 152 (1)
N1—H6⋯O1ii 0.94 (1) 2.02 (1) 2.920 (3) 159 (1)
N3—H7⋯O1iii 0.95 (1) 2.21 (1) 3.121 (3) 161 (1)
N3—H8⋯N2iv 0.95 (1) 2.37 (1) 3.214 (2) 149 (1)
C3—H1⋯O2v 0.95 (1) 2.56 (1) 3.416 (3) 150 (1)
C4—H4⋯O1 0.95 (1) 2.37 (1) 2.803 (3) 108 (1)
Symmetry codes: (i) -x, -y+1, -z; (ii) [x, -y+{\script{1\over 2}}, +z-{\script{1\over 2}}]; (iii) [-x+1, +y+{\script{1\over 2}}, -z+{\script{1\over 2}}]; (iv) [x+1, -y+{\script{1\over 2}}, +z+{\script{1\over 2}}]; (v) [-x, +y+{\script{1\over 2}}, -z-{\script{1\over 2}}].

The diffraction pattern indexed to a monoclinic cell [M(20) = 25.9, F(20) = 70.7; DICVOL-91; Boultif & Louer, 1991[Boultif, A. & Louer, D. (1991). J. Appl. Cryst. 24, 987-993.]), and space group P21/c was assigned from volume considerations and a statistical consideration of the systematic absences (Markvardsen et al., 2001[Markvardsen, A. J., David, W. I. F., Johnson, J. C. & Shankland, K. (2001). Acta Cryst. A57, 47-54.]). The data set was background subtracted and truncated to 52.2° 2θ for Pawley (1981[Pawley, G. S. (1981). J. Appl. Cryst. 14, 357-361.]) fitting (χ2Pawley = 5.17) and the structure was solved using the simulated annealing (SA) global optimization procedure (David et al., 1998[David, W. I. F., Shankland, K. & Shankland, N. (1998). Chem. Commun. pp. 931-932.]), which is now implemented in the DASH computer program (David et al., 1998[David, W. I. F., Shankland, K., Cole, J., Maginn, S., Motherwell, W. D. S. & Taylor, R. (2001). DASH. Version 3.0 User Manual. Cambridge Crystallographic Data Centre, England.]). The SA structure solution involved the optimization of one mol­ecule of HCT, totaling 7 degrees of freedom. The best SA solution had a favourable χ2SA/χ2Pawley ratio of 2.6, a chemically reasonable packing arrangement and exhibited no significant misfit to the data. Prior to Rietveld refinement, atoms H7 and H8 were set to positions which satisfied the hydrogen bonding contacts within the structure. The solved structure was subsequently refined with data in the range 6.0–62.1° 2θ using a restrained Rietveld (1969[Rietveld, H. M. (1969). J. Appl. Cryst. 2, 65-71.]) method, as implemented in TOPAS (Coelho, 2003[Coelho, A. A. (2003). TOPAS User Manual. Version 3.1. Bruker AXS GmbH, Karlsruhe, Germany.]), with the Rwp falling to 0.038 during the refinement. A joint refinement strategy was implemented, in which the structure of HCT form I (Dupont & Dideberg, 1972[Dupont, L. & Dideberg, O. (1972). Acta Cryst. B28, 2340-2347. (In French.)]) was included to take account of the impurity peaks arising from the presence of a small amount (estimated at less than 5%) of this polymorph in the sample. In the course of the refinement, the form I unit-cell and peak-shape parameters were allowed to vary, whilst all atomic coordinates were fixed. All atomic positions (including H atoms) for the form II structure were refined, subject to a series of restraints on bond lengths, bond angles and planarity. Uiso(H) values were set at 0.044 Å2. A spherical harmonics correction of intensities for preferred orientation was applied in the final refinement. The observed and calculated diffraction patterns for the refined crystal structure are shown in Fig. 1[link].

Data collection: DIFFRAC plus XRD Commander (Kienle & Jacob, 2003[Kienle, M. & Jacob, M. (2003). DIFFRAC plus XRD Commander. Version 2.3. Bruker AXS GmbH, Karlsruhe, Germany.]); cell refinement: TOPAS (Coelho, 2003[Coelho, A. A. (2003). TOPAS User Manual. Version 3.1. Bruker AXS GmbH, Karlsruhe, Germany.]); data reduction: DASH (David et al., 2001[David, W. I. F., Shankland, K., Cole, J., Maginn, S., Motherwell, W. D. S. & Taylor, R. (2001). DASH. Version 3.0 User Manual. Cambridge Crystallographic Data Centre, England.]); program(s) used to solve structure: DASH; program(s) used to refine structure: TOPAS; molecular graphics: PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]); software used to prepare material for publication: enCIFer (Allen et al., 2004[Allen, F. H., Johnson, O., Shields, G. P., Smith, B. R. & Towler, M. (2004). J. Appl. Cryst. 37, 335-338.]).

Supporting information


Computing details top

Data collection: DIFFRAC plus XRD Commander (Kienle & Jacob, 2003); data reduction: DASH (David et al., 2001); program(s) used to solve structure: DASH; program(s) used to refine structure: TOPAS (Coelho, 2003); software used to prepare material for publication: enCIFer (Allen et al., 2004).

(I) top
Crystal data top
C7H8ClN3O4S2F(000) = 608.0
Mr = 297.75Dx = 1.799 Mg m3
Monoclinic, P21/cCu Kα1 radiation, λ = 1.54056 Å
Hall symbol: -P 2ybcµ = 6.75 mm1
a = 9.4884 (5) ÅT = 298 K
b = 8.3334 (4) ÅParticle morphology: visual estimate, prisms
c = 15.1309 (7) Åwhite
β = 113.2087 (19)°cylinder, 12 × 0.7 mm
V = 1099.59 (9) Å3Specimen preparation: Prepared at 298 K
Z = 4
Data collection top
Bruker AXS D8 Advance
diffractometer
Data collection mode: transmission
Radiation source: sealed X-ray tube, Bruker-AXS D8Scan method: step
Primary focussing, Ge 111 monochromator2θmin = 5.0°, 2θmax = 65.0°, 2θstep = 0.017°
Specimen mounting: 0.7 mm borosilicate capillary
Refinement top
Least-squares matrix: selected elements only92 parameters
Rp = 0.03347 restraints
Rwp = 0.0381 constraint
Rexp = 0.023Only H-atom coordinates refined
RBragg = 0.013Weighting scheme based on measured s.u.'s 1/σ(Yobs)2
3529 data points(Δ/σ)max = 0.005
Excluded region(s): 62.1 to 65.0 due to poor signal to noiseBackground function: Chebyshev polynomial
Profile function: Fundamental parameters with axial divergence correctionPreferred orientation correction: A spherical harmonics-based preferred orientation correction was applied with Topas during the Rietveld refinement.
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cl10.75173 (15)0.1570 (3)0.12511 (14)0.0269 (4)*
S10.04110 (12)0.25043 (13)0.05257 (7)0.0269 (4)*
S20.53828 (12)0.00769 (14)0.22842 (7)0.0269 (4)*
O10.41184 (17)0.0340 (4)0.25537 (14)0.0269 (4)*
O20.0243 (4)0.1139 (3)0.1111 (2)0.0269 (4)*
O30.0117 (2)0.2956 (5)0.02000 (11)0.0269 (4)*
O40.6253 (3)0.1367 (3)0.21308 (19)0.0269 (4)*
N10.26907 (15)0.3922 (3)0.12379 (11)0.0269 (4)*
N20.02352 (17)0.41019 (14)0.11982 (8)0.0269 (4)*
N30.65720 (17)0.10948 (14)0.31064 (14)0.0269 (4)*
C10.24235 (12)0.2284 (2)0.00040 (9)0.0269 (4)*
C20.33184 (13)0.3004 (2)0.04357 (9)0.0269 (4)*
C30.10325 (14)0.39732 (15)0.18320 (9)0.0269 (4)*
C40.30954 (13)0.1390 (2)0.08259 (9)0.0269 (4)*
C50.46572 (15)0.1121 (2)0.12321 (12)0.0269 (4)*
C60.55492 (15)0.1828 (3)0.07942 (12)0.0269 (4)*
C70.49079 (13)0.2748 (2)0.00157 (9)0.0269 (4)*
H10.0814 (8)0.4892 (11)0.2234 (7)0.044*
H20.0707 (10)0.3011 (11)0.2187 (6)0.044*
H30.5541 (9)0.3160 (10)0.0320 (6)0.044*
H40.2476 (9)0.0937 (11)0.1121 (6)0.044*
H50.0555 (9)0.5041 (11)0.0813 (6)0.044*
H60.3375 (9)0.4321 (11)0.1498 (6)0.044*
H70.6580 (8)0.2158 (10)0.2881 (6)0.044*
H80.7567 (9)0.0647 (11)0.3389 (6)0.044*
Geometric parameters (Å, º) top
Cl1—C61.730 (2)N2—H50.951 (9)
S1—O21.425 (3)N3—H70.951 (8)
S1—O31.426 (2)N3—H80.946 (9)
S1—N21.6438 (16)C1—C21.3946 (19)
S1—C11.7650 (17)C1—C41.381 (2)
S2—O11.428 (2)C2—C71.4031 (19)
S2—O41.429 (3)C4—C51.381 (2)
S2—N31.633 (2)C5—C61.394 (2)
S2—C51.772 (2)C6—C71.368 (2)
N1—C21.358 (2)C3—H10.949 (9)
N1—C31.473 (2)C3—H20.947 (9)
N2—C31.441 (2)C4—H40.946 (9)
N1—H60.943 (9)C7—H30.953 (9)
O2—S1—O3119.4 (2)S1—C1—C4119.55 (11)
O2—S1—N2110.42 (13)C1—C2—C7117.82 (13)
O2—S1—C1108.92 (17)N1—C2—C1121.84 (13)
O3—S1—N2106.39 (18)N1—C2—C7120.34 (13)
O3—S1—C1109.25 (10)N1—C3—N2108.10 (11)
N2—S1—C1100.90 (10)C1—C4—C5121.48 (13)
O1—S2—O4122.35 (19)S2—C5—C4117.40 (12)
O1—S2—N3106.27 (14)S2—C5—C6124.83 (13)
O1—S2—C5105.68 (13)C4—C5—C6117.77 (15)
O4—S2—N3107.67 (14)Cl1—C6—C5121.28 (16)
O4—S2—C5108.82 (13)Cl1—C6—C7117.16 (14)
N3—S2—C5104.75 (10)C5—C6—C7121.56 (15)
C2—N1—C3123.27 (16)C2—C7—C6120.67 (13)
S1—N2—C3113.58 (11)N1—C3—H1109.0 (6)
C2—N1—H6116.1 (6)N1—C3—H2110.7 (6)
C3—N1—H6118.7 (5)N2—C3—H1109.1 (6)
S1—N2—H5110.9 (5)N2—C3—H2107.5 (6)
C3—N2—H5110.2 (6)H1—C3—H2112.3 (8)
S2—N3—H7112.6 (5)C1—C4—H4119.6 (5)
S2—N3—H8112.0 (6)C5—C4—H4118.9 (6)
H7—N3—H8112.5 (8)C2—C7—H3119.7 (5)
C2—C1—C4120.66 (12)C6—C7—H3119.5 (5)
S1—C1—C2119.80 (11)
O2—S1—N2—C362.4 (2)S1—N2—C3—N166.39 (16)
O3—S1—N2—C3166.72 (13)C2—C1—C4—C52.8 (2)
C1—S1—N2—C352.73 (12)S1—C1—C2—C7177.71 (12)
O2—S1—C1—C296.13 (19)C4—C1—C2—N1178.32 (17)
O2—S1—C1—C483.47 (19)S1—C1—C2—N12.1 (2)
O3—S1—C1—C2131.9 (2)S1—C1—C4—C5176.79 (13)
O3—S1—C1—C448.5 (2)C4—C1—C2—C71.9 (2)
N2—S1—C1—C220.07 (15)N1—C2—C7—C6179.82 (19)
N2—S1—C1—C4160.33 (13)C1—C2—C7—C60.4 (2)
O1—S2—C5—C47.5 (2)C1—C4—C5—S2178.81 (13)
O1—S2—C5—C6171.5 (2)C1—C4—C5—C62.1 (3)
O4—S2—C5—C4125.57 (18)S2—C5—C6—C7179.59 (15)
O4—S2—C5—C655.4 (2)S2—C5—C6—Cl10.7 (3)
N3—S2—C5—C4119.51 (15)C4—C5—C6—Cl1179.73 (17)
N3—S2—C5—C659.5 (2)C4—C5—C6—C70.6 (3)
C3—N1—C2—C7166.79 (16)C5—C6—C7—C20.3 (3)
C3—N1—C2—C113.0 (3)Cl1—C6—C7—C2179.46 (16)
C2—N1—C3—N244.9 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H5···O3i0.95 (1)2.03 (1)2.905 (4)152 (1)
N1—H6···O1ii0.94 (1)2.02 (1)2.920 (3)159 (1)
N3—H7···O1iii0.95 (1)2.21 (1)3.121 (3)161 (1)
N3—H8···N2iv0.95 (1)2.37 (1)3.214 (2)149 (1)
C3—H1···O2v0.95 (1)2.56 (1)3.416 (3)150 (1)
C4—H4···O10.95 (1)2.37 (1)2.803 (3)108 (1)
Symmetry codes: (i) x, y+1, z; (ii) x, y+1/2, z1/2; (iii) x+1, y+1/2, z+1/2; (iv) x+1, y+1/2, z+1/2; (v) x, y+1/2, z1/2.
 

Acknowledgements

We thank the Basic Technology programme of the UK Research Councils for funding under the project Control and Prediction of the Organic Solid State (http://www.cposs.org.uk). We also thank the CCLRC Centre for Molecular Structure and Dynamics and Pharmaceutics International Inc. (Baltimore, USA) for studentship funding for PF and SO, respectively, and the EPSRC for grant GR/N07462/01.

References

First citationAllen, F. H., Johnson, O., Shields, G. P., Smith, B. R. & Towler, M. (2004). J. Appl. Cryst. 37, 335–338. Web of Science CSD CrossRef CAS IUCr Journals
First citationBoultif, A. & Louer, D. (1991). J. Appl. Cryst. 24, 987–993. CrossRef CAS Web of Science IUCr Journals
First citationCoelho, A. A. (2003). TOPAS User Manual. Version 3.1. Bruker AXS GmbH, Karlsruhe, Germany.
First citationDavid, W. I. F., Shankland, K., Cole, J., Maginn, S., Motherwell, W. D. S. & Taylor, R. (2001). DASH. Version 3.0 User Manual. Cambridge Crystallographic Data Centre, England.
First citationDavid, W. I. F., Shankland, K. & Shankland, N. (1998). Chem. Commun. pp. 931–932. Web of Science CSD CrossRef
First citationDupont, L. & Dideberg, O. (1972). Acta Cryst. B28, 2340–2347. (In French.) CSD CrossRef CAS IUCr Journals Web of Science
First citationFlorence, A. J., Baumgartner, B., Weston, C., Shankland, N., Kennedy, A. R., Shankland, K. & David, W. I. F. (2003). J. Pharm. Sci. 92, 1930–1938. Web of Science CSD CrossRef PubMed CAS
First citationHill, R. J. & Madsen, I. C. (2002). Structure Determination from Powder Diffraction Data, edited by W. I. F. David, K. Shankland, L. B. McCusker & Ch. Baerlocher, pp.114–116. Oxford University Press.
First citationKienle, M. & Jacob, M. (2003). DIFFRAC plus XRD Commander. Version 2.3. Bruker AXS GmbH, Karlsruhe, Germany.
First citationMarkvardsen, A. J., David, W. I. F., Johnson, J. C. & Shankland, K. (2001). Acta Cryst. A57, 47–54. Web of Science CrossRef CAS IUCr Journals
First citationPawley, G. S. (1981). J. Appl. Cryst. 14, 357–361. CrossRef CAS Web of Science IUCr Journals
First citationRietveld, H. M. (1969). J. Appl. Cryst. 2, 65–71. CrossRef CAS IUCr Journals Web of Science
First citationShankland, K., David, W. I. F. & Sivia, D. S. (1997). J. Mater. Chem. 7, 569–572. CSD CrossRef CAS
First citationSpek, A. L. (2003). J. Appl. Cryst. 36, 7–13. Web of Science CrossRef CAS IUCr Journals

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