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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

4-Sulfamoylanilinium perchlorate

aDepartment of Physics, Regional centre of Anna University, Tirunelveli Region, Tirunelveli 627 007, India, bDepartment of Physics, University College of Engineering, Nagercoil, Anna University, Tirunelveli Region, Nagercoil 629 004, India, and cLaboratory of X-ray Crystallography, Indian Institute of Chemical Technology, Hyderabad 500 607, India
*Correspondence e-mail: physics.autt@gmail.com

(Received 8 June 2013; accepted 29 June 2013; online 10 July 2013)

In the crystal of the title salt, C6H9N2O2S+·ClO4, the components are linked by N—H⋯O hydrogen bonds, forming a three-dimensional network. The cations are connected along a and b axes, leading to linear and zigzag C(3) and C(8) chain motifs, respectively. A cation–anion inter­action along the c axis leads to a C22(12) chain motif. R33(18) and R33(20) ring motifs are observed as cation–anion-type inter­actions. These hydrogen-bonding ring and chain motifs are localized at z = 0 or 1, leading to alternate hydro­philic and hydro­phobic regions along the c axis as a result of the stacking of anions and the aromatic cationic parts.

Related literature

For the first use of sulfanilamide, see: Buttle et al. (1936[Buttle, G. A. H., Grey, W. H. & Stephenson, D. (1936). Lancet, 1, 1286-1290.]). For related structures, see: Ravikumar et al. (2013[Ravikumar, B., Pandiarajan, S. & Athimoolam, S. (2013). Acta Cryst. E69, o596.]); Pandiarajan et al. (2011[Pandiarajan, S., Balasubramanian, S., Ravikumar, B. & Athimoolam, S. (2011). Acta Cryst. E67, o2788.]); Topacli & Kesimli (2001[Topacli, A. & Kesimli, B. (2001). Sepctrosc. Lett. 34, 513-526.]). For graph-set motifs, see Etter et al. (1990[Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256-262.]).

[Scheme 1]

Experimental

Crystal data
  • C6H9N2O2S+·ClO4

  • Mr = 272.66

  • Monoclinic, P 21

  • a = 4.9158 (10) Å

  • b = 10.514 (2) Å

  • c = 9.814 (2) Å

  • β = 93.716 (3)°

  • V = 506.15 (18) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.60 mm−1

  • T = 293 K

  • 0.24 × 0.16 × 0.12 mm

Data collection
  • Bruker SMART APEX CCD area-detector diffractometer

  • 5796 measured reflections

  • 2367 independent reflections

  • 2361 reflections with I > 2σ(I)

  • Rint = 0.023

Refinement
  • R[F2 > 2σ(F2)] = 0.022

  • wR(F2) = 0.061

  • S = 1.08

  • 2367 reflections

  • 166 parameters

  • 5 restraints

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

  • Δρmax = 0.31 e Å−3

  • Δρmin = −0.26 e Å−3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 1287 Friedel pairs

  • Flack parameter: 0.00 (4)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1A⋯O1i 0.88 (1) 2.12 (1) 2.953 (2) 160 (3)
N1—H1B⋯O6ii 0.88 (3) 2.30 (3) 3.086 (2) 149 (2)
N2—H2A⋯O5i 0.88 (1) 2.19 (1) 3.044 (2) 164 (3)
N2—H2B⋯O2iii 0.88 (1) 2.16 (2) 2.876 (2) 139 (2)
N2—H2C⋯O4iv 0.88 (1) 2.30 (2) 2.858 (2) 122 (2)
N2—H2C⋯O5 0.88 (1) 2.37 (2) 3.058 (2) 136 (2)
Symmetry codes: (i) x+1, y, z; (ii) [-x+1, y+{\script{1\over 2}}, -z+1]; (iii) [-x+2, y+{\script{1\over 2}}, -z+1]; (iv) [-x+1, y+{\script{1\over 2}}, -z].

Data collection: SMART (Bruker, 2001[Bruker (2001). SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2001[Bruker (2001). SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL/PC (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL/PC; molecular graphics: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: SHELXTL/PC.

Supporting information


Comment top

Sulfa drugs, mostly the derivatives of sulfanilamide, have been an integral part of our medical history. They were the first effective chemotherapeutic agents to be widely used for the treatment of bacterial infection in humans and animals (Topacli & Kesimli, 2001). The uses of Sulfanilamide, was started during 1936 (Buttle et al., 1936) and the grandparent of the sulfonamide family of drugs that are still in use today. The nitrate and sulfate complexes of sulfanilamide (Pandiarajan et al., 2011; Ravikumar et al., 2013) were already reported. In continuation of our interest on the sulfanilamide complexes, the synthesis of the title compound and its title structure,bis(4-sulfamoylanilinium) sulfate, is described here. In the title structure, a protonated sulfomylanilinium cation and a perchlorate anion constitute the asymmetric part (Fig. 1). The protonation on the one of N sites is confirmed from C—N bond distance. The geometrical parameters of the cation are in agreement with the reported sulfomylanilinium structures in 4-sulfomylanilinium nitrate (Pandiarajan et al., 2011) and Bis(4-sulfomylanilinium) sulfate (Ravikumar et al., 2013).

The crystal structure is stabilized through intricate three dimensional hydrogen bonding network formed through N—H···O interactions (Table 1; Fig. 2). All the hydrogen atoms attached to both the nitrogen atoms of the cation is involved in the hydrogen bonding interactions as donors. All the oxygen atoms in the cation and anion, except the O3 atom present in the anion, are acting as acceptor atoms and involved in the hydrogen bonding interactions. One of the N—H···O hydrogen bonds is observed to be bifurcated hydrogen bond, with one donor hydrogen (Table 1): N2—H3N···O4 (-x + 1, y + 1/2, -z) and N2—H3N···O5. Among the hydrogen bonds, two are cation-cation type and other four hydrogen bonds are cation-anion type. In the cation-cation type, N1—H2N···O1(1 + x, y, z) is making a chain C(3) motif extending along a-axis of the unit cell. Another N2—H5N···O2(2 - x, 1/2 + y, 1 - z) hydrogen bond is connecting the cations along b-axis of the unit cell through zigzag chain C(8) motifs. Thus cations are connected directly only along a & b-axes. Whereas along c-axis the interactions are cation-anion type, i.e., the cations and anions are connected through N1—H1N···O6(-x + 1, y + 1/2, -z + 1) and N2—H3N···O4(-x + 1, y + 1/2, -z) hydrogen bonds leading to chain C22(12) motif.

Further, cations and anions are connected through N1—H2N···O1(1 + x, y, z), N2—H3N···O5 and N2—H4N···O5(1 + x, y, z) leading to a ring R33(18) motifs. Another ring R33(20) motif is formed through N1—H1N···O6(-x + 1, y + 1/2, -z + 1), N2—H4N···O5(1 + x, y, z) and N2—H5N···O2(-x + 2, y + 1/2, -z + 1) hydrogen bonds. These ring R33(20) motifs are arranged adjacently and making a chain C33(10) motif extending along b-axis of the unit cell. These hydrogen bonding ring and chain motifs are localized at z = 0 or z = 1 leading to alternate hydrophilic and hydrophobic regions along c axis as a result of the stacking of anions and the aromatic cationic parts.

Related literature top

For related structures, see Buttle et al. (1936); Ravikumar et al. (2013); Pandiarajan et al. (2011); Topacli & Kesimli (2001). For graph-set motifs, see Etter et al. (1990).

Experimental top

The synthesis of the title compound was carried out by heating of the mixture of sulphanilamide (1.7 g) and perchloric acid (0.5 ml of 98%)in water with the stoichiometric ratio of 1:1 (at 60°C) under reflux for 1 h. Colourless needle type crystals of the title compound suitable for single-crystal X-ray analysis with the approximate size of 1.8 cm τimes 0.6 cm τimes 0.4 cm were obtained by slow evaporation at room temperature. The measured sample was cut from a bigger crystal. Caution: Although no problems were encountered in this work, perchlorate compounds are potentially explosive. They should be prepared in small amounts and handled with care.

Refinement top

All the H atoms except the atoms involved in hydrogen bonds were positioned geometrically and refined using a riding model, with C—H = 0.93 Å and Uiso(H) = 1.2 Ueq (parent atom). H atoms involved in hydrogen bonds were located from differential fourier map and refined isotropically with the distance restraint (DFIX) for appropriate distance (0.88 (1) Å). From the measured 5796 total reflections, 1287 are Friedel opposites.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXTL/PC (Sheldrick, 2008); program(s) used to refine structure: SHELXTL/PC (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXTL/PC (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The title molecule with the atom numbering scheme. The displacement ellipsoids are shown at the 50% probability level.
[Figure 2] Fig. 2. Packing diagram of the title compound viewed down the aaxis. The H-bonds are shown as dashed lines.
4-Sulfomylanilinium perchlorate top
Crystal data top
C6H9N2O2S+·ClO4F(000) = 280
Mr = 272.66Dx = 1.789 Mg m3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ybCell parameters from 2412 reflections
a = 4.9158 (10) Åθ = 2.5–24.7°
b = 10.514 (2) ŵ = 0.60 mm1
c = 9.814 (2) ÅT = 293 K
β = 93.716 (3)°Needle, colourless
V = 506.15 (18) Å30.24 × 0.16 × 0.12 mm
Z = 2
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
2361 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.023
Graphite monochromatorθmax = 28.0°, θmin = 2.1°
ω scansh = 66
5796 measured reflectionsk = 1313
2367 independent reflectionsl = 1212
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.022 w = 1/[σ2(Fo2) + (0.0315P)2 + 0.1129P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.061(Δ/σ)max = 0.001
S = 1.08Δρmax = 0.31 e Å3
2367 reflectionsΔρmin = 0.26 e Å3
166 parametersExtinction correction: SHELXTL/PC (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
5 restraintsExtinction coefficient: 0.189 (7)
Primary atom site location: structure-invariant direct methodsAbsolute structure: Flack (1983), 1287 Friedel pairs
Secondary atom site location: difference Fourier mapAbsolute structure parameter: 0.00 (4)
Crystal data top
C6H9N2O2S+·ClO4V = 506.15 (18) Å3
Mr = 272.66Z = 2
Monoclinic, P21Mo Kα radiation
a = 4.9158 (10) ŵ = 0.60 mm1
b = 10.514 (2) ÅT = 293 K
c = 9.814 (2) Å0.24 × 0.16 × 0.12 mm
β = 93.716 (3)°
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
2361 reflections with I > 2σ(I)
5796 measured reflectionsRint = 0.023
2367 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.022H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.061Δρmax = 0.31 e Å3
S = 1.08Δρmin = 0.26 e Å3
2367 reflectionsAbsolute structure: Flack (1983), 1287 Friedel pairs
166 parametersAbsolute structure parameter: 0.00 (4)
5 restraints
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

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
C10.8057 (3)0.53210 (15)0.53535 (15)0.0244 (3)
C21.0030 (3)0.46394 (16)0.47189 (16)0.0295 (3)
H21.09190.39640.51690.035*
C31.0672 (3)0.49695 (19)0.34095 (16)0.0293 (3)
H31.19980.45230.29730.035*
C40.9310 (3)0.59698 (15)0.27676 (15)0.0235 (3)
C50.7316 (3)0.66524 (16)0.33789 (17)0.0281 (3)
H50.64190.73200.29200.034*
C60.6676 (3)0.63237 (17)0.46891 (17)0.0294 (3)
H60.53380.67680.51190.035*
N10.9084 (3)0.58560 (16)0.80644 (15)0.0315 (3)
N20.9994 (3)0.63135 (15)0.13833 (15)0.0279 (3)
O10.4527 (2)0.51671 (14)0.71892 (14)0.0380 (3)
O20.8370 (3)0.36510 (13)0.72799 (14)0.0385 (3)
H1A1.0834 (17)0.578 (3)0.797 (3)0.070 (9)*
H1B0.847 (5)0.665 (3)0.803 (3)0.047 (7)*
H2A1.120 (4)0.584 (2)0.100 (3)0.055 (7)*
H2B1.052 (5)0.7108 (9)0.134 (3)0.053 (8)*
H2C0.863 (4)0.617 (3)0.078 (2)0.048 (7)*
Cl10.58672 (7)0.34769 (3)0.07752 (4)0.02621 (11)
O30.8773 (2)0.34793 (17)0.06980 (15)0.0409 (3)
O40.4686 (3)0.26701 (16)0.02835 (16)0.0477 (4)
O50.4874 (3)0.47611 (13)0.05900 (15)0.0399 (3)
O60.5169 (3)0.30181 (14)0.20823 (15)0.0445 (3)
S10.73500 (7)0.49156 (3)0.70441 (4)0.02528 (11)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0265 (7)0.0256 (7)0.0217 (7)0.0006 (6)0.0055 (5)0.0017 (5)
C20.0328 (7)0.0291 (8)0.0268 (7)0.0085 (6)0.0034 (6)0.0022 (6)
C30.0318 (7)0.0310 (8)0.0258 (7)0.0071 (7)0.0066 (5)0.0021 (6)
C40.0246 (6)0.0244 (7)0.0217 (6)0.0033 (5)0.0026 (5)0.0002 (5)
C50.0295 (8)0.0260 (8)0.0289 (7)0.0051 (6)0.0039 (6)0.0046 (6)
C60.0286 (7)0.0294 (8)0.0311 (8)0.0067 (6)0.0091 (6)0.0020 (7)
N10.0303 (7)0.0361 (8)0.0285 (7)0.0003 (6)0.0048 (6)0.0044 (6)
N20.0309 (7)0.0293 (7)0.0239 (6)0.0016 (6)0.0045 (5)0.0020 (6)
O10.0264 (6)0.0523 (9)0.0362 (6)0.0018 (5)0.0090 (5)0.0027 (6)
O20.0532 (8)0.0281 (7)0.0355 (6)0.0052 (6)0.0131 (5)0.0080 (5)
Cl10.02693 (18)0.02327 (17)0.02901 (19)0.00278 (13)0.00626 (12)0.00363 (14)
O30.0255 (6)0.0483 (7)0.0495 (7)0.0003 (6)0.0069 (5)0.0073 (7)
O40.0489 (8)0.0478 (8)0.0466 (9)0.0168 (7)0.0033 (7)0.0193 (7)
O50.0413 (7)0.0271 (7)0.0522 (8)0.0048 (6)0.0092 (6)0.0027 (6)
O60.0560 (8)0.0424 (8)0.0366 (7)0.0042 (6)0.0155 (6)0.0060 (6)
S10.02663 (18)0.02599 (19)0.02388 (17)0.00010 (14)0.00668 (12)0.00191 (14)
Geometric parameters (Å, º) top
C1—C21.386 (2)N1—S11.6113 (16)
C1—C61.393 (2)N1—H1A0.875 (5)
C1—S11.7692 (15)N1—H1B0.88 (3)
C2—C31.387 (2)N2—H2A0.877 (5)
C2—H20.9300N2—H2B0.876 (5)
C3—C41.377 (2)N2—H2C0.876 (5)
C3—H30.9300O1—S11.4289 (13)
C4—C51.383 (2)O2—S11.4345 (14)
C4—N21.466 (2)Cl1—O61.4328 (14)
C5—C61.387 (2)Cl1—O41.4345 (14)
C5—H50.9300Cl1—O31.4355 (12)
C6—H60.9300Cl1—O51.4432 (14)
C2—C1—C6121.01 (14)H1A—N1—H1B115 (3)
C2—C1—S1118.86 (12)C4—N2—H2A117.2 (19)
C6—C1—S1120.12 (12)C4—N2—H2B111.4 (18)
C1—C2—C3119.67 (15)H2A—N2—H2B108 (3)
C1—C2—H2120.2C4—N2—H2C111.9 (18)
C3—C2—H2120.2H2A—N2—H2C97 (3)
C4—C3—C2118.80 (15)H2B—N2—H2C110 (3)
C4—C3—H3120.6O6—Cl1—O4109.89 (10)
C2—C3—H3120.6O6—Cl1—O3110.16 (9)
C3—C4—C5122.36 (15)O4—Cl1—O3108.68 (9)
C3—C4—N2118.57 (14)O6—Cl1—O5109.20 (9)
C5—C4—N2119.06 (14)O4—Cl1—O5110.13 (10)
C4—C5—C6118.85 (14)O3—Cl1—O5108.75 (9)
C4—C5—H5120.6O1—S1—O2119.15 (9)
C6—C5—H5120.6O1—S1—N1107.62 (8)
C5—C6—C1119.31 (14)O2—S1—N1107.65 (9)
C5—C6—H6120.3O1—S1—C1107.46 (7)
C1—C6—H6120.3O2—S1—C1106.66 (7)
S1—N1—H1A111 (2)N1—S1—C1107.86 (8)
S1—N1—H1B112.7 (17)
C6—C1—C2—C30.9 (3)C2—C1—C6—C50.8 (2)
S1—C1—C2—C3177.99 (13)S1—C1—C6—C5178.07 (13)
C1—C2—C3—C40.3 (3)C2—C1—S1—O1147.96 (13)
C2—C3—C4—C50.3 (3)C6—C1—S1—O133.10 (16)
C2—C3—C4—N2179.92 (15)C2—C1—S1—O219.12 (16)
C3—C4—C5—C60.4 (2)C6—C1—S1—O2161.93 (14)
N2—C4—C5—C6179.99 (15)C2—C1—S1—N196.28 (15)
C4—C5—C6—C10.2 (2)C6—C1—S1—N182.67 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O1i0.88 (1)2.12 (1)2.953 (2)160 (3)
N1—H1B···O6ii0.88 (3)2.30 (3)3.086 (2)149 (2)
N2—H2A···O5i0.88 (1)2.19 (1)3.044 (2)164 (3)
N2—H2B···O2iii0.88 (1)2.16 (2)2.876 (2)139 (2)
N2—H2C···O4iv0.88 (1)2.30 (2)2.858 (2)122 (2)
N2—H2C···O50.88 (1)2.37 (2)3.058 (2)136 (2)
Symmetry codes: (i) x+1, y, z; (ii) x+1, y+1/2, z+1; (iii) x+2, y+1/2, z+1; (iv) x+1, y+1/2, z.

Experimental details

Crystal data
Chemical formulaC6H9N2O2S+·ClO4
Mr272.66
Crystal system, space groupMonoclinic, P21
Temperature (K)293
a, b, c (Å)4.9158 (10), 10.514 (2), 9.814 (2)
β (°) 93.716 (3)
V3)506.15 (18)
Z2
Radiation typeMo Kα
µ (mm1)0.60
Crystal size (mm)0.24 × 0.16 × 0.12
Data collection
DiffractometerBruker SMART APEX CCD area-detector
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
5796, 2367, 2361
Rint0.023
(sin θ/λ)max1)0.660
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.022, 0.061, 1.08
No. of reflections2367
No. of parameters166
No. of restraints5
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.31, 0.26
Absolute structureFlack (1983), 1287 Friedel pairs
Absolute structure parameter0.00 (4)

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXTL/PC (Sheldrick, 2008), PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O1i0.88 (1)2.12 (1)2.953 (2)160 (3)
N1—H1B···O6ii0.88 (3)2.30 (3)3.086 (2)149 (2)
N2—H2A···O5i0.88 (1)2.19 (1)3.044 (2)164 (3)
N2—H2B···O2iii0.88 (1)2.16 (2)2.876 (2)139 (2)
N2—H2C···O4iv0.88 (1)2.30 (2)2.858 (2)122 (2)
N2—H2C···O50.88 (1)2.37 (2)3.058 (2)136 (2)
Symmetry codes: (i) x+1, y, z; (ii) x+1, y+1/2, z+1; (iii) x+2, y+1/2, z+1; (iv) x+1, y+1/2, z.
 

Acknowledgements

SA is grateful to the Department of Science and Technology, SERB, for the financial support of this work in the form of the Fast-track Research Project scheme.

References

First citationBruker (2001). SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationButtle, G. A. H., Grey, W. H. & Stephenson, D. (1936). Lancet, 1, 1286–1290.  CrossRef
First citationEtter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256–262.  CrossRef CAS Web of Science IUCr Journals
First citationFlack, H. D. (1983). Acta Cryst. A39, 876–881.  CrossRef CAS Web of Science IUCr Journals
First citationPandiarajan, S., Balasubramanian, S., Ravikumar, B. & Athimoolam, S. (2011). Acta Cryst. E67, o2788.  Web of Science CSD CrossRef IUCr Journals
First citationRavikumar, B., Pandiarajan, S. & Athimoolam, S. (2013). Acta Cryst. E69, o596.  CSD CrossRef IUCr Journals
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals
First citationTopacli, A. & Kesimli, B. (2001). Sepctrosc. Lett. 34, 513–526.  Web of Science CrossRef CAS

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds