organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

5-Carb­­oxy-2,4-dihy­dr­oxy­anilinium chloride

aInstitute of Chemical Sciences, University of Peshawar, Peshawar, Pakistan, and bDepartment of Physics, University of Sargodha, Sargodha, Pakistan
*Correspondence e-mail: dmntahir_uos@yahoo.com

(Received 15 August 2010; accepted 18 August 2010; online 21 August 2010)

In the title salt, C7H8NO4+·Cl, the organic group is planar with an r.m.s. deviation of 0.0265 Å. An S(6) ring motif is formed due to an intra­molecular O—H⋯O hydrogen bond. The compound consists of dimers due to inter­molecular O—H⋯O hydrogen bonds with an R22(8) ring motif. The dimers are inter­linked through strong N—H⋯Cl and O—H⋯Cl hydrogen bonds, resulting in a three-dimensional polymeric network.

Related literature

For related structures, see: Bendjeddou et al. (2009[Bendjeddou, L., Cherouana, A., Hadjadj, N., Dahaoui, S. & Lecomte, C. (2009). Acta Cryst. E65, o1770-o1771.]); Dobson & Gerkin (1998[Dobson, A. J. & Gerkin, R. E. (1998). Acta Cryst. C54, 1632-1634.]). For graph-set notation, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]).

[Scheme 1]

Experimental

Crystal data
  • C7H8NO4+·Cl

  • Mr = 205.59

  • Monoclinic, P 21 /n

  • a = 5.0667 (3) Å

  • b = 28.4071 (13) Å

  • c = 6.3966 (3) Å

  • β = 97.649 (3)°

  • V = 912.47 (8) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.40 mm−1

  • T = 296 K

  • 0.28 × 0.18 × 0.16 mm

Data collection
  • Bruker Kappa APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2005[Bruker (2005). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.926, Tmax = 0.935

  • 7094 measured reflections

  • 1635 independent reflections

  • 1108 reflections with I > 2σ(I)

  • Rint = 0.052

Refinement
  • R[F2 > 2σ(F2)] = 0.044

  • wR(F2) = 0.098

  • S = 1.01

  • 1635 reflections

  • 128 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.23 e Å−3

  • Δρmin = −0.22 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H1⋯O2i 0.85 (3) 1.81 (3) 2.653 (3) 177 (4)
N1—H1A⋯Cl1ii 0.89 2.24 3.124 (3) 176
N1—H1B⋯Cl1iii 0.89 2.29 3.176 (3) 173
N1—H1C⋯Cl1iv 0.89 2.35 3.217 (2) 163
O3—H3⋯O2 0.85 (4) 1.84 (3) 2.632 (3) 154 (3)
O4—H4A⋯Cl1v 0.85 (3) 2.15 (3) 2.985 (2) 170 (3)
Symmetry codes: (i) -x+2, -y, -z; (ii) x-1, y, z-1; (iii) x, y, z-1; (iv) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]; (v) x-1, y, z.

Data collection: APEX2 (Bruker, 2009[Bruker (2009). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2009[Bruker (2009). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]) and PLATON.

Supporting information


Comment top

The title compound (I, Fig. 1) has been prepared for derivatization and for the synthesis of metallic complexes.

The crystal structure of (II) i.e., 5-ammoniosalicylic Acid chloride monohydrate (Dobson & Gerkin, 1998) and (III) i.e., bis(3-carboxyanilinum) bis(perchlorate) monohydrate (Bendjeddou et al., 2009) have been published which are related to the title compound.

In (I), the organic group (C1—C7/O1—O4/N1) is planar with r. m. s. deviation of 0.0265 Å. There exist a strong intramolecular H-bond of O—H···O type (Table 1, Fig. 1) completing an S(6) ring motif (Bernstein et al., 1995) in the organic part. The title compound consists of dimers due to intermolecular H-bond of O—H···O type (Table 1, Fig. 2) completing R22(8) ring motif. The dimers are interlinked through strong H-bondings of N—H···Cl and O—H···Cl types (Table 1, Fig. 2) resulting in a three dimensional polymeric network.

Related literature top

For related structures, see: Bendjeddou et al. (2009); Dobson & Gerkin (1998). For graph-set notation, see: Bernstein et al. (1995).

Experimental top

Concentrated nitric acid (2 mL, 67%) was added drop by drop to β-resorcylic acid (1 g, 97%, 6.3 mmol) in a round bottom flask. The mixture was protected from moisture by CaCl2 (anhydrous) tube and was allowed to stand for 12 h at room temperature. Then the reaction mixture was diluted with water. The crude material was filtered and recrystallized from water to affoard the 5-nitro-β-resorcylic acid.

Then a mixture of 5-nitro-β-resorcylic acid (1.5 g, 7.5 mmol), tin (3 g, 25 mmol), concentrated hydrochloric acid (8 ml, 37%) and absolute ethanol (5 ml) were taken in a 100 ml round bottom flask and heated under reflux with stirring for 40 min. The completion of the reaction was monitored by TLC. The reaction mixture was filtered to remove any unreacted tin. The filtrate was kept for seven days to afford light green prisms of (I).

Refinement top

The coordinates of H-atoms of hydroxy groups were refined. The H-atoms were positioned geometrically (N—H = 0.89, C–H = 0.93 Å) and refined as riding with Uiso(H) = xUeq(C, N, O), where x = 1.2 for all H-atoms.

Structure description top

The title compound (I, Fig. 1) has been prepared for derivatization and for the synthesis of metallic complexes.

The crystal structure of (II) i.e., 5-ammoniosalicylic Acid chloride monohydrate (Dobson & Gerkin, 1998) and (III) i.e., bis(3-carboxyanilinum) bis(perchlorate) monohydrate (Bendjeddou et al., 2009) have been published which are related to the title compound.

In (I), the organic group (C1—C7/O1—O4/N1) is planar with r. m. s. deviation of 0.0265 Å. There exist a strong intramolecular H-bond of O—H···O type (Table 1, Fig. 1) completing an S(6) ring motif (Bernstein et al., 1995) in the organic part. The title compound consists of dimers due to intermolecular H-bond of O—H···O type (Table 1, Fig. 2) completing R22(8) ring motif. The dimers are interlinked through strong H-bondings of N—H···Cl and O—H···Cl types (Table 1, Fig. 2) resulting in a three dimensional polymeric network.

For related structures, see: Bendjeddou et al. (2009); Dobson & Gerkin (1998). For graph-set notation, see: Bernstein et al. (1995).

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. View of the title compound with the atom numbering scheme. The displacement ellipsoids are drawn at the 50% probability level. H-atoms are shown as small spheres of arbitrary radii. The dotted line represents the intramolecular H-bonding.
[Figure 2] Fig. 2. The partial packing (PLATON; Spek, 2009) which shows that molecules form dimers which are interlinked through H-bondings to form a three-dimensional polymeric network.
5-Carboxy-2,4-dihydroxyanilinium chloride top
Crystal data top
C7H8NO4+·ClF(000) = 424
Mr = 205.59Dx = 1.497 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 1108 reflections
a = 5.0667 (3) Åθ = 2.9–25.2°
b = 28.4071 (13) ŵ = 0.40 mm1
c = 6.3966 (3) ÅT = 296 K
β = 97.649 (3)°Prism, light green
V = 912.47 (8) Å30.28 × 0.18 × 0.16 mm
Z = 4
Data collection top
Bruker Kappa APEXII CCD
diffractometer
1635 independent reflections
Radiation source: fine-focus sealed tube1108 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.052
Detector resolution: 8.10 pixels mm-1θmax = 25.2°, θmin = 2.9°
ω scansh = 56
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
k = 3432
Tmin = 0.926, Tmax = 0.935l = 77
7094 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.044Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.098H atoms treated by a mixture of independent and constrained refinement
S = 1.01 w = 1/[σ2(Fo2) + (0.036P)2 + 0.4226P]
where P = (Fo2 + 2Fc2)/3
1635 reflections(Δ/σ)max < 0.001
128 parametersΔρmax = 0.23 e Å3
0 restraintsΔρmin = 0.22 e Å3
Crystal data top
C7H8NO4+·ClV = 912.47 (8) Å3
Mr = 205.59Z = 4
Monoclinic, P21/nMo Kα radiation
a = 5.0667 (3) ŵ = 0.40 mm1
b = 28.4071 (13) ÅT = 296 K
c = 6.3966 (3) Å0.28 × 0.18 × 0.16 mm
β = 97.649 (3)°
Data collection top
Bruker Kappa APEXII CCD
diffractometer
1635 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
1108 reflections with I > 2σ(I)
Tmin = 0.926, Tmax = 0.935Rint = 0.052
7094 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0440 restraints
wR(F2) = 0.098H atoms treated by a mixture of independent and constrained refinement
S = 1.01Δρmax = 0.23 e Å3
1635 reflectionsΔρmin = 0.22 e Å3
128 parameters
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

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.8567 (5)0.05383 (8)0.1244 (4)0.0527 (8)
O20.7828 (4)0.01248 (8)0.1583 (3)0.0553 (8)
O30.4286 (5)0.04378 (8)0.3905 (4)0.0620 (10)
O40.0113 (4)0.18833 (7)0.1726 (3)0.0498 (8)
N10.2950 (5)0.19898 (8)0.1420 (4)0.0404 (8)
C10.7367 (6)0.04694 (11)0.0429 (5)0.0420 (11)
C20.5471 (5)0.08321 (10)0.0823 (4)0.0373 (10)
C30.4020 (6)0.08012 (10)0.2540 (5)0.0404 (10)
C40.2197 (6)0.11460 (10)0.2882 (5)0.0415 (11)
C50.1841 (6)0.15295 (10)0.1561 (4)0.0366 (10)
C60.3332 (6)0.15690 (10)0.0114 (4)0.0343 (9)
C70.5084 (6)0.12258 (10)0.0495 (4)0.0376 (10)
Cl10.75184 (16)0.19834 (3)0.56278 (12)0.0476 (3)
H10.974 (7)0.0328 (12)0.131 (5)0.0632*
H1A0.139930.197100.225190.0485*
H1B0.426490.201300.220800.0485*
H1C0.295150.224250.059700.0485*
H30.543 (7)0.0264 (13)0.342 (5)0.0743*
H40.121360.111860.400410.0498*
H4A0.063 (6)0.1874 (11)0.284 (5)0.0597*
H70.602910.125340.164020.0451*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0541 (15)0.0463 (15)0.0613 (14)0.0190 (11)0.0212 (13)0.0073 (11)
O20.0518 (14)0.0443 (14)0.0728 (15)0.0160 (12)0.0189 (12)0.0144 (12)
O30.0706 (18)0.0536 (16)0.0664 (16)0.0192 (13)0.0267 (14)0.0218 (13)
O40.0599 (15)0.0434 (14)0.0525 (13)0.0153 (12)0.0311 (12)0.0053 (10)
N10.0393 (14)0.0373 (15)0.0483 (14)0.0049 (12)0.0195 (12)0.0009 (12)
C10.0349 (18)0.0375 (18)0.0538 (19)0.0028 (15)0.0067 (16)0.0026 (16)
C20.0321 (16)0.0322 (17)0.0480 (18)0.0030 (14)0.0073 (14)0.0010 (14)
C30.0410 (18)0.0357 (18)0.0453 (18)0.0028 (15)0.0085 (15)0.0084 (14)
C40.0448 (19)0.0414 (19)0.0415 (17)0.0006 (16)0.0179 (15)0.0034 (15)
C50.0361 (18)0.0348 (18)0.0406 (16)0.0005 (14)0.0116 (14)0.0047 (14)
C60.0343 (16)0.0297 (17)0.0409 (16)0.0009 (13)0.0125 (14)0.0028 (13)
C70.0346 (17)0.0381 (18)0.0417 (16)0.0014 (14)0.0115 (14)0.0018 (14)
Cl10.0500 (5)0.0494 (5)0.0480 (4)0.0043 (4)0.0240 (4)0.0048 (4)
Geometric parameters (Å, º) top
O1—C11.314 (4)N1—H1C0.8900
O2—C11.230 (4)C1—C21.453 (4)
O3—C31.347 (4)C2—C71.399 (4)
O4—C51.346 (4)C2—C31.403 (4)
O1—H10.85 (3)C3—C41.384 (4)
O3—H30.85 (4)C4—C51.376 (4)
O4—H4A0.85 (3)C5—C61.395 (4)
N1—C61.456 (4)C6—C71.362 (4)
N1—H1A0.8900C4—H40.9300
N1—H1B0.8900C7—H70.9300
Cl1···N1i3.176 (3)C1···C1vi3.580 (4)
Cl1···N1ii3.124 (3)C1···O2vi3.245 (4)
Cl1···C7i3.622 (3)C1···O2v3.357 (4)
Cl1···O4iii2.985 (2)C1···C4iii3.335 (4)
Cl1···N1iv3.217 (2)C2···C4iii3.598 (4)
Cl1···H4Aiii2.15 (3)C3···C1viii3.587 (4)
Cl1···H1Aii2.2400C4···C2viii3.598 (4)
Cl1···H1Bi2.2900C4···C1viii3.335 (4)
Cl1···H1Civ2.3500C7···O4iii3.322 (4)
Cl1···H7i2.8800C7···Cl1ix3.622 (3)
O1···O2v2.653 (3)C1···H1v2.72 (3)
O2···O32.632 (3)C1···H32.34 (3)
O2···C1vi3.245 (4)H1···O2v1.81 (3)
O2···O1v2.653 (3)H1···C1v2.72 (3)
O2···C1v3.357 (4)H1···H1v2.50 (5)
O3···O3vii2.899 (3)H1A···Cl1x2.2400
O3···O22.632 (3)H1A···O42.7200
O4···N12.642 (3)H1B···H72.3500
O4···Cl1viii2.985 (2)H1B···Cl1ix2.2900
O4···C7viii3.322 (4)H1C···O42.4300
O1···H72.4000H1C···Cl1xi2.3500
O2···H31.84 (3)H3···C12.34 (3)
O2···H1v1.81 (3)H3···O21.84 (3)
O3···H3vii2.62 (3)H3···H3vii2.60 (5)
O4···H1C2.4300H3···O3vii2.62 (3)
O4···H1A2.7200H4···H4A2.4200
N1···Cl1ix3.176 (3)H4A···H42.4200
N1···Cl1x3.124 (3)H4A···Cl1viii2.15 (3)
N1···O42.642 (3)H7···Cl1ix2.8800
N1···Cl1xi3.217 (2)H7···O12.4000
C1···C3iii3.587 (4)H7···H1B2.3500
C1—O1—H1110 (2)O3—C3—C4116.8 (3)
C3—O3—H3103 (2)C2—C3—C4120.7 (3)
C5—O4—H4A114 (2)O3—C3—C2122.5 (3)
C6—N1—H1C109.00C3—C4—C5120.0 (3)
H1A—N1—H1B109.00C4—C5—C6119.7 (3)
C6—N1—H1A109.00O4—C5—C6115.1 (2)
C6—N1—H1B109.00O4—C5—C4125.2 (3)
H1B—N1—H1C109.00N1—C6—C5117.5 (3)
H1A—N1—H1C109.00N1—C6—C7121.7 (2)
O1—C1—C2115.1 (3)C5—C6—C7120.8 (3)
O1—C1—O2122.4 (3)C2—C7—C6120.5 (3)
O2—C1—C2122.5 (3)C3—C4—H4120.00
C1—C2—C7120.4 (2)C5—C4—H4120.00
C3—C2—C7118.4 (3)C2—C7—H7120.00
C1—C2—C3121.2 (3)C6—C7—H7120.00
O1—C1—C2—C3179.2 (3)O3—C3—C4—C5179.4 (3)
O1—C1—C2—C71.8 (4)C2—C3—C4—C51.6 (5)
O2—C1—C2—C31.2 (5)C3—C4—C5—O4179.3 (3)
O2—C1—C2—C7177.8 (3)C3—C4—C5—C60.2 (4)
C1—C2—C3—O30.2 (4)O4—C5—C6—N12.6 (4)
C1—C2—C3—C4179.2 (3)O4—C5—C6—C7177.7 (3)
C7—C2—C3—O3179.2 (3)C4—C5—C6—N1177.8 (3)
C7—C2—C3—C41.8 (4)C4—C5—C6—C71.9 (4)
C1—C2—C7—C6179.2 (3)N1—C6—C7—C2178.0 (3)
C3—C2—C7—C60.2 (4)C5—C6—C7—C21.7 (4)
Symmetry codes: (i) x, y, z+1; (ii) x+1, y, z+1; (iii) x+1, y, z; (iv) x+1/2, y+1/2, z+1/2; (v) x+2, y, z; (vi) x+1, y, z; (vii) x+1, y, z+1; (viii) x1, y, z; (ix) x, y, z1; (x) x1, y, z1; (xi) x1/2, y+1/2, z1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O2v0.85 (3)1.81 (3)2.653 (3)177 (4)
N1—H1A···Cl1x0.892.243.124 (3)176
N1—H1B···Cl1ix0.892.293.176 (3)173
N1—H1C···Cl1xi0.892.353.217 (2)163
O3—H3···O20.85 (4)1.84 (3)2.632 (3)154 (3)
O4—H4A···Cl1viii0.85 (3)2.15 (3)2.985 (2)170 (3)
Symmetry codes: (v) x+2, y, z; (viii) x1, y, z; (ix) x, y, z1; (x) x1, y, z1; (xi) x1/2, y+1/2, z1/2.

Experimental details

Crystal data
Chemical formulaC7H8NO4+·Cl
Mr205.59
Crystal system, space groupMonoclinic, P21/n
Temperature (K)296
a, b, c (Å)5.0667 (3), 28.4071 (13), 6.3966 (3)
β (°) 97.649 (3)
V3)912.47 (8)
Z4
Radiation typeMo Kα
µ (mm1)0.40
Crystal size (mm)0.28 × 0.18 × 0.16
Data collection
DiffractometerBruker Kappa APEXII CCD
Absorption correctionMulti-scan
(SADABS; Bruker, 2005)
Tmin, Tmax0.926, 0.935
No. of measured, independent and
observed [I > 2σ(I)] reflections
7094, 1635, 1108
Rint0.052
(sin θ/λ)max1)0.600
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.044, 0.098, 1.01
No. of reflections1635
No. of parameters128
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.23, 0.22

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2009), WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O2i0.85 (3)1.81 (3)2.653 (3)177 (4)
N1—H1A···Cl1ii0.892.243.124 (3)176
N1—H1B···Cl1iii0.892.293.176 (3)173
N1—H1C···Cl1iv0.892.353.217 (2)163
O3—H3···O20.85 (4)1.84 (3)2.632 (3)154 (3)
O4—H4A···Cl1v0.85 (3)2.15 (3)2.985 (2)170 (3)
Symmetry codes: (i) x+2, y, z; (ii) x1, y, z1; (iii) x, y, z1; (iv) x1/2, y+1/2, z1/2; (v) x1, y, z.
 

Acknowledgements

The authors acknowledge the provision of funds for the purchase of diffractometer and encouragement by Dr Muhammad Akram Chaudhary, Vice Chancellor, University of Sargodha, Pakistan.

References

First citationBendjeddou, L., Cherouana, A., Hadjadj, N., Dahaoui, S. & Lecomte, C. (2009). Acta Cryst. E65, o1770–o1771.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationBernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.  CrossRef CAS Web of Science Google Scholar
First citationBruker (2005). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationBruker (2009). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationDobson, A. J. & Gerkin, R. E. (1998). Acta Cryst. C54, 1632–1634.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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