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

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ISSN: 2056-9890

Di­chloridobis(4-fluoro­aniline-κN)zinc

aCrystal Growth and Thin Film Laboratory, School of Physics, Bharathidasan University, Tiruchirappalli, Tamil Nadu 620 024, India, and bInstitute of Physics, University of Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
*Correspondence e-mail: krmurthin@yahoo.co.in, helen.stoeckli-evans@unine.ch

(Received 27 July 2012; accepted 29 July 2012; online 4 August 2012)

In the title compound, [ZnCl2(C6H6FN)2], the ZnII atom has a slightly distorted tetra­hedral geometry, being coordinated by the N atoms of two 4-fluoro­aniline mol­ecules and the two Cl anions. The two benzene rings are almost perpendicular to one another, making a dihedral angle of 89.96 (13)°. In the crystal, mol­ecules are linked via pairs of N—H⋯Cl hydrogen bonds, forming chains propagating along the b axis. These chains are in turn linked via a second pair of N—H⋯Cl hydrogen bonds, forming a two-dimensional network parallel to the ab plane. The title compound crystallizes in the space group Pca21 and exhibits weak second harmonic generation (SHG) properties.

Related literature

For the measurement of second harmonic generation (SHG) conversion efficiency, see: Kurtz & Perry (1968[Kurtz, S. K. & Perry, T. T. (1968). J. Appl. Phys. 39, 3798-3813.]). For the crystal structure of dichlorido-bis­(p-chloro­aniline)zinc, see: Subashini et al. (2012a[Subashini, A., Ramamurthi, K. & Stoeckli-Evans, H. (2012a). Private communication (deposition number CCDC-894044). CCDC, Cambridge, England.]) and for the crystal structure of dichlorodo-bis­(p-bromo­aniline)zinc, see: Subashini et al. (2012b[Subashini, A., Ramamurthi, K. & Stoeckli-Evans, H. (2012b). Private communication (deposition number CCDC-894045). CCDC, Cambridge, England.]); Feng et al. (2003[Feng, Y.-L., Lin, J.-J. & Lin, H. (2003). Zhejiang Shifan Daxue Xuebao, Ziran Kexueban (Chin. J. Zhejiang Normal Univ., Nat. Sci.), 26, 39-41.]).

[Scheme 1]

Experimental

Crystal data
  • [ZnCl2(C6H6FN)2]

  • Mr = 358.51

  • Orthorhombic, P c a 21

  • a = 11.6817 (5) Å

  • b = 4.7080 (2) Å

  • c = 25.2056 (15) Å

  • V = 1386.24 (12) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 2.17 mm−1

  • T = 173 K

  • 0.45 × 0.22 × 0.10 mm

Data collection
  • Stoe IPDS 2 diffractometer

  • Absorption correction: multi-scan (MULscanABS in PLATON; Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]) Tmin = 0.742, Tmax = 0.805

  • 7963 measured reflections

  • 2613 independent reflections

  • 2465 reflections with I > 2σ(I)

  • Rint = 0.031

Refinement
  • R[F2 > 2σ(F2)] = 0.020

  • wR(F2) = 0.043

  • S = 1.02

  • 2613 reflections

  • 172 parameters

  • 1 restraint

  • H-atom parameters constrained

  • Δρmax = 0.21 e Å−3

  • Δρmin = −0.32 e Å−3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 1273 Friedel pairs

  • Flack parameter: 0.013 (10)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1B⋯Cl2i 0.92 2.63 3.436 (2) 147
N2—H2B⋯Cl1i 0.92 2.55 3.380 (2) 151
N1—H1A⋯Cl2ii 0.92 2.59 3.479 (2) 162
N2—H2A⋯Cl1iii 0.92 2.55 3.439 (2) 162
Symmetry codes: (i) x, y+1, z; (ii) [x+{\script{1\over 2}}, -y+2, z]; (iii) [x-{\script{1\over 2}}, -y+2, z].

Data collection: X-AREA (Stoe & Cie, 2009[Stoe & Cie. (2009). X-AREA and X-RED32. Stoe & Cie GmbH, Darmstadt, Germany.]); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2009[Stoe & Cie. (2009). X-AREA and X-RED32. Stoe & Cie GmbH, Darmstadt, Germany.]); 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: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]) and Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]); software used to prepare material for publication: SHELXL97, PLATON and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Comment top

In our search for compounds exhibiting second harmonic generation (SHG) properties we have synthesized a series of ZnCl2 complexes of p-halogen substituted anilines. The title compound, the ZnCl2 complex of p-fluoroaniline crystallized in the noncentrosymmetric orthorhombic space group Pca21, while the p-chloroaniline (Subashini et al., 2012a) and p-bromoaniline (Subashini et al., 2012b; Feng et al., 2003) ZnCl2 complexes crystallized in the centrosymmetric monoclinic space group C2/c and both molecules have crystallographic 2-fold rotation symmetry.

In the title compound (Fig. 1), the zinc atom has a slightly distorted tetrahedral geometry, being coordinated by the atoms N1 and N2 of two p-fluoroaniline molecules and the two Cl- anions. The two benzene rings (C1—C6 and C7—C12) are perpendicular to one another with a dihedral angle of 89.96 (13)°. In the p-chloroaniline and p-bromoaniline ZnCl2 complexes mentioned above the same angles are 80.65 (16) and 80.0 (3)°, respectively.

In the crystal of the title compound, molecules are linked via a pair of N—H···Cl hydrogen bonds forming chains propagating along the b axis direction. These chains are in turn linked via a second pair of N—H···Cl hydrogen bonds to form a two-dimensional network lying parallel to the ab plane (Table 1 and Fig. 2). This contrasts with the packing in the crystals of the p-chloroaniline and p-bromoaniline ZnCl2 complexes. There molecules are linked by four N—H···halogen bonds to form chains propagating along [010], with no significant interactions between the chains.

As the title compound crystallized in a noncentrosymmetric space group it was decided to measure the second harmonic generation (SHG) properties of all three compounds; dichloro-bis(p-fluoroaniline)zinc, dichloro-bis(p-chloroaniline)zinc and dichloro-bis(p-bromoaniline)zinc. The SHG conversion efficiency was determined by the powder technique developed by (Kurtz & Perry, 1968). The crystals were powdered and the fine powdered samples were inserted in a micro-capillary tube and then subjected to a Q-switched Nd: YAG laser emitting 1064 nm radiation with 3.9 mJ/pulse. The frequency doubling was confirmed by the emission of green radiation of wavelength 532 nm collected by a monochromator after separating the 1064 nm pump beam with an IR-blocking filter. A detector connected to a power meter was used to detect the second harmonic intensity.

The output beam voltage produced by dichloro-bis(p-fluoroaniline)zinc, dichloro-bis(p-chloroaniline)zinc and dichloro-bis(p-bromoaniline)zinc derivatives were 15, 3 and 10 mV, respectively. The same quantity of crystalline KDP (potassium dihydrogen phosphate) powder, used as a reference material, produced 140 mV as output beam voltage. Hence the three samples exhibits SHG efficiency of only ca 0.11, 0.02 and 0.07 times that of the KDP.

Related literature top

For the measurement of second harmonic generation (SHG) conversion efficiency, see: Kurtz & Perry (1968). For the crystal structure of dichloro-bis(p-chloroaniline)zinc, see: Subashini et al. (2012a) and for the crystal structure of dichloro-bis(p-bromoaniline)zinc, see: Subashini et al. (2012b); Feng et al. (2003).

Experimental top

The title compound was prepared by the condensation reaction of p-fluoroaniline with ZnCl2 in a 1:1 molar ratio. The reaction mixture was dissolved in methanol and heated under reflux for 6 h. The resulting solution was filtered and allowed to evaporate. Colourless rod-like crystals of the title compound, suitable for X-ray diffraction analysis, were obtained in a period of ca 7 days. The same method was used for the preparation of the p-chloroaniline and p-bromoaniline ZnCl2 complexes.

Refinement top

All the H atoms could be located in a difference Fourier map. In the final cycles of refinement they were included in calculated positions and treated as riding atoms: N—H = 0.92 Å and C—H = 0.95 Å with Uiso(H) = 1.2Ueq(N or C).

Computing details top

Data collection: X-AREA (Stoe & Cie, 2009); cell refinement: X-AREA (Stoe & Cie, 2009); data reduction: X-RED32 (Stoe & Cie, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. A view of the molecular structure of the title compound with the atom numbering. The displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. A view along the c axis of the crystal packing of the title compound. The N—H···Cl hydrogen bonds are shown as dashed cyan lines (see Table 1 for details).
Dichloridobis(4-fluoroaniline-κN)zinc top
Crystal data top
[ZnCl2(C6H6FN)2]F(000) = 720
Mr = 358.51Dx = 1.718 Mg m3
Orthorhombic, Pca21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2acCell parameters from 10039 reflections
a = 11.6817 (5) Åθ = 1.6–26.1°
b = 4.7080 (2) ŵ = 2.17 mm1
c = 25.2056 (15) ÅT = 173 K
V = 1386.24 (12) Å3Rod, colourless
Z = 40.45 × 0.22 × 0.10 mm
Data collection top
Stoe IPDS 2
diffractometer
2613 independent reflections
Radiation source: fine-focus sealed tube2465 reflections with I > 2σ(I)
Plane graphite monochromatorRint = 0.031
ϕ and ω scansθmax = 25.6°, θmin = 1.6°
Absorption correction: multi-scan
(MULscanABS in PLATON; Spek, 2009)
h = 1412
Tmin = 0.742, Tmax = 0.805k = 55
7963 measured reflectionsl = 3030
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.020H-atom parameters constrained
wR(F2) = 0.043 w = 1/[σ2(Fo2) + (0.0253P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.02(Δ/σ)max = 0.001
2613 reflectionsΔρmax = 0.21 e Å3
172 parametersΔρmin = 0.32 e Å3
1 restraintAbsolute structure: Flack (1983), 1273 Friedel pairs
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.013 (10)
Crystal data top
[ZnCl2(C6H6FN)2]V = 1386.24 (12) Å3
Mr = 358.51Z = 4
Orthorhombic, Pca21Mo Kα radiation
a = 11.6817 (5) ŵ = 2.17 mm1
b = 4.7080 (2) ÅT = 173 K
c = 25.2056 (15) Å0.45 × 0.22 × 0.10 mm
Data collection top
Stoe IPDS 2
diffractometer
2613 independent reflections
Absorption correction: multi-scan
(MULscanABS in PLATON; Spek, 2009)
2465 reflections with I > 2σ(I)
Tmin = 0.742, Tmax = 0.805Rint = 0.031
7963 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.020H-atom parameters constrained
wR(F2) = 0.043Δρmax = 0.21 e Å3
S = 1.02Δρmin = 0.32 e Å3
2613 reflectionsAbsolute structure: Flack (1983), 1273 Friedel pairs
172 parametersAbsolute structure parameter: 0.013 (10)
1 restraint
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
Zn10.11820 (2)0.94853 (5)0.29991 (2)0.0175 (1)
Cl10.24924 (5)0.67311 (13)0.25893 (2)0.0231 (2)
Cl20.01369 (5)0.66951 (13)0.33956 (2)0.0224 (2)
F10.24874 (17)0.4882 (4)0.53656 (6)0.0375 (5)
F20.00539 (17)0.6379 (4)0.05020 (6)0.0386 (6)
N10.19821 (18)1.1742 (4)0.35892 (7)0.0190 (6)
N20.03682 (17)1.1921 (5)0.24427 (7)0.0193 (6)
C10.2140 (2)1.0033 (5)0.40640 (10)0.0173 (8)
C20.3039 (2)0.8160 (6)0.40935 (9)0.0206 (8)
C30.3164 (2)0.6390 (6)0.45336 (9)0.0236 (8)
C40.2366 (2)0.6601 (6)0.49308 (9)0.0267 (8)
C50.1466 (2)0.8448 (7)0.49146 (10)0.0279 (8)
C60.1343 (2)1.0192 (6)0.44767 (12)0.0247 (9)
C70.0273 (2)1.0505 (5)0.19283 (10)0.0181 (7)
C80.1041 (2)1.1133 (7)0.15318 (10)0.0242 (9)
C90.0976 (3)0.9741 (7)0.10479 (11)0.0305 (9)
C100.0127 (2)0.7762 (6)0.09785 (9)0.0263 (8)
C110.0645 (2)0.7084 (6)0.13658 (10)0.0258 (8)
C120.0570 (2)0.8484 (6)0.18522 (9)0.0236 (8)
H1A0.268401.235600.347000.0230*
H1B0.155101.331700.367100.0230*
H20.357900.806900.381200.0250*
H2A0.035401.236200.256300.0230*
H2B0.076401.359500.240000.0230*
H30.378200.508300.455700.0280*
H50.093300.853400.519900.0340*
H60.072201.148800.445700.0300*
H80.161701.252400.158900.0290*
H90.150601.014700.077200.0370*
H110.121900.569300.130500.0310*
H120.109400.805200.212900.0280*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Zn10.0174 (1)0.0186 (1)0.0167 (1)0.0009 (1)0.0010 (1)0.0002 (2)
Cl10.0180 (3)0.0236 (3)0.0277 (3)0.0019 (3)0.0033 (2)0.0017 (2)
Cl20.0187 (3)0.0224 (3)0.0261 (3)0.0031 (3)0.0034 (2)0.0004 (2)
F10.0460 (9)0.0433 (11)0.0232 (8)0.0064 (9)0.0048 (9)0.0147 (6)
F20.0423 (10)0.0516 (13)0.0218 (7)0.0015 (9)0.0016 (6)0.0145 (7)
N10.0200 (10)0.0179 (11)0.0191 (9)0.0029 (9)0.0014 (8)0.0020 (8)
N20.0215 (11)0.0185 (11)0.0180 (10)0.0010 (10)0.0011 (8)0.0016 (8)
C10.0214 (13)0.0145 (15)0.0161 (13)0.0048 (10)0.0028 (10)0.0017 (8)
C20.0168 (12)0.0252 (15)0.0199 (12)0.0052 (11)0.0001 (9)0.0016 (10)
C30.0199 (13)0.0231 (14)0.0277 (13)0.0009 (11)0.0043 (10)0.0005 (10)
C40.0335 (15)0.0261 (14)0.0204 (12)0.0074 (13)0.0050 (10)0.0044 (10)
C50.0295 (14)0.0329 (17)0.0214 (12)0.0033 (14)0.0073 (11)0.0003 (12)
C60.0221 (15)0.0241 (17)0.0279 (15)0.0057 (13)0.0006 (11)0.0025 (10)
C70.0200 (12)0.0171 (12)0.0172 (12)0.0035 (11)0.0028 (10)0.0009 (10)
C80.0232 (14)0.0240 (17)0.0254 (14)0.0010 (13)0.0010 (10)0.0001 (11)
C90.0298 (15)0.040 (2)0.0216 (13)0.0025 (14)0.0068 (11)0.0018 (11)
C100.0305 (14)0.0306 (15)0.0179 (12)0.0081 (13)0.0026 (10)0.0057 (11)
C110.0213 (12)0.0277 (16)0.0284 (14)0.0025 (12)0.0050 (10)0.0069 (11)
C120.0241 (13)0.0254 (14)0.0212 (13)0.0008 (12)0.0021 (10)0.0005 (10)
Geometric parameters (Å, º) top
Zn1—Cl12.2565 (7)C4—C51.365 (4)
Zn1—Cl22.2579 (7)C5—C61.383 (4)
Zn1—N12.0530 (19)C7—C81.375 (3)
Zn1—N22.046 (2)C7—C121.383 (3)
F1—C41.370 (3)C8—C91.387 (4)
F2—C101.369 (3)C9—C101.372 (4)
N1—C11.454 (3)C10—C111.367 (3)
N2—C71.462 (3)C11—C121.395 (4)
N1—H1B0.9200C2—H20.9500
N1—H1A0.9200C3—H30.9500
N2—H2A0.9200C5—H50.9500
N2—H2B0.9200C6—H60.9500
C1—C61.398 (4)C8—H80.9500
C1—C21.373 (3)C9—H90.9500
C2—C31.395 (4)C11—H110.9500
C3—C41.372 (3)C12—H120.9500
Cl1—Zn1—Cl2109.34 (2)C1—C6—C5119.5 (2)
Cl1—Zn1—N1108.68 (6)N2—C7—C12119.4 (2)
Cl1—Zn1—N2108.88 (6)N2—C7—C8119.8 (2)
Cl2—Zn1—N1106.92 (6)C8—C7—C12120.8 (2)
Cl2—Zn1—N2108.21 (6)C7—C8—C9120.1 (3)
N1—Zn1—N2114.72 (8)C8—C9—C10118.2 (3)
Zn1—N1—C1111.58 (14)F2—C10—C11118.3 (2)
Zn1—N2—C7112.81 (16)F2—C10—C9118.7 (2)
C1—N1—H1A109.00C9—C10—C11123.0 (2)
C1—N1—H1B109.00C10—C11—C12118.4 (2)
H1A—N1—H1B108.00C7—C12—C11119.5 (2)
Zn1—N1—H1B109.00C1—C2—H2120.00
Zn1—N1—H1A109.00C3—C2—H2120.00
Zn1—N2—H2B109.00C2—C3—H3121.00
Zn1—N2—H2A109.00C4—C3—H3121.00
H2A—N2—H2B108.00C4—C5—H5121.00
C7—N2—H2A109.00C6—C5—H5121.00
C7—N2—H2B109.00C1—C6—H6120.00
N1—C1—C6119.9 (2)C5—C6—H6120.00
N1—C1—C2119.8 (2)C7—C8—H8120.00
C2—C1—C6120.2 (2)C9—C8—H8120.00
C1—C2—C3120.4 (2)C8—C9—H9121.00
C2—C3—C4117.8 (2)C10—C9—H9121.00
C3—C4—C5123.2 (2)C10—C11—H11121.00
F1—C4—C3118.1 (2)C12—C11—H11121.00
F1—C4—C5118.7 (2)C7—C12—H12120.00
C4—C5—C6118.8 (2)C11—C12—H12120.00
Cl1—Zn1—N1—C180.53 (15)C2—C3—C4—F1179.6 (2)
Cl2—Zn1—N1—C137.40 (16)C2—C3—C4—C50.1 (4)
N2—Zn1—N1—C1157.37 (14)F1—C4—C5—C6179.8 (2)
Cl1—Zn1—N2—C731.74 (16)C3—C4—C5—C60.3 (4)
Cl2—Zn1—N2—C787.00 (15)C4—C5—C6—C10.2 (4)
N1—Zn1—N2—C7153.74 (15)N2—C7—C8—C9178.2 (3)
Zn1—N1—C1—C280.9 (2)C12—C7—C8—C90.1 (4)
Zn1—N1—C1—C695.7 (2)N2—C7—C12—C11178.5 (2)
Zn1—N2—C7—C898.8 (2)C8—C7—C12—C110.5 (4)
Zn1—N2—C7—C1279.2 (2)C7—C8—C9—C100.5 (4)
N1—C1—C2—C3176.3 (2)C8—C9—C10—F2179.9 (2)
C6—C1—C2—C30.3 (4)C8—C9—C10—C110.8 (5)
N1—C1—C6—C5176.6 (2)F2—C10—C11—C12179.8 (2)
C2—C1—C6—C50.1 (4)C9—C10—C11—C120.5 (4)
C1—C2—C3—C40.2 (4)C10—C11—C12—C70.2 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1B···Cl2i0.922.633.436 (2)147
N2—H2B···Cl1i0.922.553.380 (2)151
N1—H1A···Cl2ii0.922.593.479 (2)162
N2—H2A···Cl1iii0.922.553.439 (2)162
Symmetry codes: (i) x, y+1, z; (ii) x+1/2, y+2, z; (iii) x1/2, y+2, z.

Experimental details

Crystal data
Chemical formula[ZnCl2(C6H6FN)2]
Mr358.51
Crystal system, space groupOrthorhombic, Pca21
Temperature (K)173
a, b, c (Å)11.6817 (5), 4.7080 (2), 25.2056 (15)
V3)1386.24 (12)
Z4
Radiation typeMo Kα
µ (mm1)2.17
Crystal size (mm)0.45 × 0.22 × 0.10
Data collection
DiffractometerStoe IPDS 2
diffractometer
Absorption correctionMulti-scan
(MULscanABS in PLATON; Spek, 2009)
Tmin, Tmax0.742, 0.805
No. of measured, independent and
observed [I > 2σ(I)] reflections
7963, 2613, 2465
Rint0.031
(sin θ/λ)max1)0.608
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.020, 0.043, 1.02
No. of reflections2613
No. of parameters172
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.21, 0.32
Absolute structureFlack (1983), 1273 Friedel pairs
Absolute structure parameter0.013 (10)

Computer programs: X-AREA (Stoe & Cie, 2009), X-RED32 (Stoe & Cie, 2009), SHELXS97 (Sheldrick, 2008), PLATON (Spek, 2009) and Mercury (Macrae et al., 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1B···Cl2i0.922.633.436 (2)147
N2—H2B···Cl1i0.922.553.380 (2)151
N1—H1A···Cl2ii0.922.593.479 (2)162
N2—H2A···Cl1iii0.922.553.439 (2)162
Symmetry codes: (i) x, y+1, z; (ii) x+1/2, y+2, z; (iii) x1/2, y+2, z.
 

Acknowledgements

AS thanks the University Grants Commission, India, for the award of a Research Fellowship in Sciences for Meritorious Students [File No. 4–1/2008 (BSR)]. HSE thanks the XRD Application Laboratory, CSEM, Neuchâtel, for access to the X-ray diffraction equipment.

References

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