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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

4-Nitro­anilinium triiodide monohydrate

aMolecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private bag, PO Wits 2050, South Africa
*Correspondence e-mail: dave.billing@wits.ac.za

(Received 4 March 2010; accepted 21 April 2010; online 28 April 2010)

In the title compound, C6H7N2O2+·I3·H2O, the triiodide anions form two-dimensional sheets along the a and c axes. These sheets are separated by the 4-nitro­anilinium cations and water mol­ecules, which form part of an extended hydrogen-bonded chain with the triiodide along the c axis, represented by the graph set C33(14). The second important hydrogen-bonding inter­action is between the nitro group, the water mol­ecule and the anilinium group, which forms an R22(6) ring and may be the reason for the deviation of the torsion angle between the benzene ring and the nitro group from 180 to 163.2 (4)°. These two strong hydrogen-bonding inter­actions also cause the benzene rings to pack off-centre from one another, with an edge-on-edge ππ stacking distance of 3.634 (6) Å and a centroid–centroid separation of 4.843 (2) Å.

Related literature

For structures of 4-nitro­anilinine-monohalide salts, see: Lemmerer & Billing (2006[Lemmerer, A. & Billing, D. G. (2006). Acta Cryst. E62, o1562-o1564.]) (bromine) and Ploug-Sørensen & Andersen (1982[Ploug-Sørensen, G. & Andersen, E. K. (1982). Acta Cryst. B38, 671-673.]) (chlorine). For other amine-based triiodide salts, see: Tebbe & Loukili (1998[Tebbe, K. F. & Loukili, R. (1998). Z. Anorg. Allg. Chem. 624, 1175-1186.]). For a triiodide salt containing a tetra­phenyl­phospho­nium cation, see: Parvez et al. (1996[Parvez, M., Wang, M. & Boorman, P. M. (1996). Acta Cryst. C52, 377-378.]). For structure-properties relationships in trihalides, see: Shibaeva & Yagubskii (2004[Shibaeva, R. P. & Yagubskii, E. B. (2004). Chem. Rev. 104, 5347-5378]). For graph-set analysis, see: Etter et al. (1990[Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256-262.]).

[Scheme 1]

Experimental

Crystal data
  • C6H7N2O2+·I3·H2O

  • Mr = 537.85

  • Monoclinic, P 21 /c

  • a = 4.8429 (9) Å

  • b = 14.701 (3) Å

  • c = 18.346 (3) Å

  • β = 91.916 (3)°

  • V = 1305.4 (4) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 7.17 mm−1

  • T = 298 K

  • 0.54 × 0.31 × 0.11 mm

Data collection
  • Bruker SMART 1K CCD area-detector diffractometer

  • Absorption correction: integration (XPREP; Bruker, 1999[Bruker (1999). SAINT-Plus (includes XPREP). Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.113, Tmax = 0.506

  • 8741 measured reflections

  • 3150 independent reflections

  • 2461 reflections with I > 2σ(I)

  • Rint = 0.068

Refinement
  • R[F2 > 2σ(F2)] = 0.034

  • wR(F2) = 0.081

  • S = 1.05

  • 3150 reflections

  • 137 parameters

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

  • Δρmax = 0.71 e Å−3

  • Δρmin = −1.42 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N2—H2A⋯O3i 0.89 1.94 2.824 (5) 173
N2—H2B⋯I3ii 0.89 3.01 3.731 (4) 139
N2—H2C⋯O1iii 0.89 2.52 2.922 (5) 108
N2—H2C⋯O3iii 0.89 2.02 2.860 (5) 157
O3—H3A⋯O2 0.88 (2) 1.98 (3) 2.818 (5) 158 (6)
O3—H3B⋯I1iv 0.89 (5) 2.88 (5) 3.722 (3) 157 (4)
Symmetry codes: (i) [x-1, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]; (ii) -x, -y+1, -z+1; (iii) [x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]; (iv) -x+1, -y+1, -z.

Data collection: SMART-NT (Bruker, 1998[Bruker (1998). SMART-NT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SMART-NT; data reduction: SAINT-Plus (Bruker, 1999[Bruker (1999). SAINT-Plus (includes XPREP). Bruker AXS Inc., Madison, Wisconsin, USA.]); program(s) used to solve structure: XS in SHELXTL (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 DIAMOND (Brandenburg, 1999[Brandenburg, K. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]) and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

Previously 4-nitroanilinine was crystallized with bromine (Lemmerer & Billing, 2006) and chlorine (Ploug-Sørensen et al., 1982) to produce the respective monohalide salts. In an attempt to synthesize a monoiodide salt with 4-nitroaniline, the black crystals of 4-nitroanilinium triiodide monohydrate, C6H7N2O2+ I3- . H2O (I) formed in preference, and the structure is reported here. Polyiodide salts are commonly found, but the triiodides less so. Tebbe & Loukili (1998) have successfully synthesized two tertiary ammonium triiodide salts, while Parvez et al. (1996) synthesized a tetraphenylphosphonium triiodide salt. This is important to note since the title compound has a primary amine as the cation, while in the other three reported cases, bulky counter cations are involved. There are no other structural similarities with (I) with the exception of the the I1—I2—I3 bond angle [178.209 (14)°], which compares with those of the tertiary ammonium triiodides (180, 177.09°) and the bulkier tetraphenylphosphonium triiodide (175.27°).

In the structure of (I) (Figs. 1, 2), the triiodide anions essentially form two-dimensional sheets along the a and c axes. Looking at the interactions along the a axis, the layers of triiodide anions pack parallel to each other with a separation of 4.843 (1) Å. The two intermolecular head-to-tail I1···I1 and the two I3···I3 interactions along the c axis have a separation of 4.574 (1) and 3.772 (1) Å and 4.1079 (7) and 5.2776 (8) Å respectively, completing the interactions which form the two-dimensional sheets. These sheets are separated by the 4-nitroanilium and water moieties which form part of an extended hydrogen-bonded chain with the triiodide along the c axis of the unit cell, represented by the graph set C33(14) (Etter et al., 1990). The graph set notation includes H···I hydrogen bonds with the water and the nitro oxygen (O2) i.e. (O3—H···O2), as seen in Fig 2.

Besides the strong C33(14) hydrogen-bonding network, another important hydrogen-bonding association is between the nitro group, the water and the ammonium group, forming an R22(6) ring (Table 1). This ring appears to be an important interaction which gives a deviation of the torsion angle C6—C1—N1—O2 between the benzene ring and the nitro group from 180° to 163.2 (4)°. The two strong hydrogen-bonding interactions result in the benzene rings packing off-centre from one another with an edge-on-edge π-π stacking distance of 3.634 (6) Å and a centroid-to-centroid separation of 4.843 (2) Å. The many short intermolecular distances between the triiodide anions and the benzene rings may be important in the optical properties of (I), regarding charge-transfer interactions and conductivity, as found in this type of compound (Shibaeva & Yagubskii, 2004).

Related literature top

For structures of 4-nitroanilinine-monohalide salts, see: Lemmerer & Billing (2006) (bromine) and Ploug-Sørensen et al. (1982) (chlorine). For other amine based triodide salts, see: Tebbe & Loukili (1998). For a triiodide salt containing a tetraphenylphosphonium cation, see: Parvez et al. (1996). For structure-properties relationships in trihalides, see: Shibaeva & Yagubskii (2004). For graph-set analysis, see: Etter et al. (1990).

Experimental top

For the preparation of (I) 0.632 g of 4-nitroaniline was dissolved in 4 ml of 55% aqueous HI. The solution was heated to dissolve the precipitate and then left to stand at room temperature. Crystals suitable for single crystal X-ray diffraction were grown by slow evaporation of the solvent over a period of one month.

Refinement top

The H atoms on nitroaniline were refined using a riding-model, with C—H = 0.93 Å, N—H = 0.89 Å and with Uĩso(H) = 1.2Ueq(C) or 1.5Ueq(N). The H atoms on the water were placed from the difference Fourier map with O—H = 0.90 (2) Å and constrained using the DFIX constraint (Sheldrick, 2008). The highest residual electron density peak (0.708eÅ-3) was 0.865 Å from I2.

Structure description top

Previously 4-nitroanilinine was crystallized with bromine (Lemmerer & Billing, 2006) and chlorine (Ploug-Sørensen et al., 1982) to produce the respective monohalide salts. In an attempt to synthesize a monoiodide salt with 4-nitroaniline, the black crystals of 4-nitroanilinium triiodide monohydrate, C6H7N2O2+ I3- . H2O (I) formed in preference, and the structure is reported here. Polyiodide salts are commonly found, but the triiodides less so. Tebbe & Loukili (1998) have successfully synthesized two tertiary ammonium triiodide salts, while Parvez et al. (1996) synthesized a tetraphenylphosphonium triiodide salt. This is important to note since the title compound has a primary amine as the cation, while in the other three reported cases, bulky counter cations are involved. There are no other structural similarities with (I) with the exception of the the I1—I2—I3 bond angle [178.209 (14)°], which compares with those of the tertiary ammonium triiodides (180, 177.09°) and the bulkier tetraphenylphosphonium triiodide (175.27°).

In the structure of (I) (Figs. 1, 2), the triiodide anions essentially form two-dimensional sheets along the a and c axes. Looking at the interactions along the a axis, the layers of triiodide anions pack parallel to each other with a separation of 4.843 (1) Å. The two intermolecular head-to-tail I1···I1 and the two I3···I3 interactions along the c axis have a separation of 4.574 (1) and 3.772 (1) Å and 4.1079 (7) and 5.2776 (8) Å respectively, completing the interactions which form the two-dimensional sheets. These sheets are separated by the 4-nitroanilium and water moieties which form part of an extended hydrogen-bonded chain with the triiodide along the c axis of the unit cell, represented by the graph set C33(14) (Etter et al., 1990). The graph set notation includes H···I hydrogen bonds with the water and the nitro oxygen (O2) i.e. (O3—H···O2), as seen in Fig 2.

Besides the strong C33(14) hydrogen-bonding network, another important hydrogen-bonding association is between the nitro group, the water and the ammonium group, forming an R22(6) ring (Table 1). This ring appears to be an important interaction which gives a deviation of the torsion angle C6—C1—N1—O2 between the benzene ring and the nitro group from 180° to 163.2 (4)°. The two strong hydrogen-bonding interactions result in the benzene rings packing off-centre from one another with an edge-on-edge π-π stacking distance of 3.634 (6) Å and a centroid-to-centroid separation of 4.843 (2) Å. The many short intermolecular distances between the triiodide anions and the benzene rings may be important in the optical properties of (I), regarding charge-transfer interactions and conductivity, as found in this type of compound (Shibaeva & Yagubskii, 2004).

For structures of 4-nitroanilinine-monohalide salts, see: Lemmerer & Billing (2006) (bromine) and Ploug-Sørensen et al. (1982) (chlorine). For other amine based triodide salts, see: Tebbe & Loukili (1998). For a triiodide salt containing a tetraphenylphosphonium cation, see: Parvez et al. (1996). For structure-properties relationships in trihalides, see: Shibaeva & Yagubskii (2004). For graph-set analysis, see: Etter et al. (1990).

Computing details top

Data collection: SMART-NT (Bruker, 1998); cell refinement: SMART-NT (Bruker, 1998); data reduction: SAINT-Plus (Bruker, 1999); program(s) used to solve structure: XS in SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. View of (I) (50% probability displacement ellipsoids)
[Figure 2] Fig. 2. A view along the a axis of an extended unit cell showing the alignment of the triiodide moieties and C33(14) H-bonding interaction.
4-Nitroanilinium triiodide monohydrate top
Crystal data top
C6H7N2O2+·I3·H2OF(000) = 968
Mr = 537.85Dx = 2.737 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 9074 reflections
a = 4.8429 (9) Åθ = 2.6–28.3°
b = 14.701 (3) ŵ = 7.17 mm1
c = 18.346 (3) ÅT = 298 K
β = 91.916 (3)°Plate, black
V = 1305.4 (4) Å30.54 × 0.31 × 0.11 mm
Z = 4
Data collection top
Bruker SMART 1K CCD area-detector
diffractometer
2461 reflections with I > 2σ(I)
φ and ω scansRint = 0.068
Absorption correction: integration
(XPREP; Bruker, 1999)
θmax = 28°, θmin = 1.8°
Tmin = 0.113, Tmax = 0.506h = 64
8741 measured reflectionsk = 1918
3150 independent reflectionsl = 2424
Refinement top
Refinement on F2H atoms treated by a mixture of independent and constrained refinement
Least-squares matrix: full w = 1/[σ2(Fo2) + (0.0374P)2 + 0.3561P]
where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.034(Δ/σ)max = 0.001
wR(F2) = 0.081Δρmax = 0.71 e Å3
S = 1.05Δρmin = 1.42 e Å3
3150 reflectionsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
137 parametersExtinction coefficient: 0.0166 (6)
0 restraints
Crystal data top
C6H7N2O2+·I3·H2OV = 1305.4 (4) Å3
Mr = 537.85Z = 4
Monoclinic, P21/cMo Kα radiation
a = 4.8429 (9) ŵ = 7.17 mm1
b = 14.701 (3) ÅT = 298 K
c = 18.346 (3) Å0.54 × 0.31 × 0.11 mm
β = 91.916 (3)°
Data collection top
Bruker SMART 1K CCD area-detector
diffractometer
3150 independent reflections
Absorption correction: integration
(XPREP; Bruker, 1999)
2461 reflections with I > 2σ(I)
Tmin = 0.113, Tmax = 0.506Rint = 0.068
8741 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0340 restraints
wR(F2) = 0.081H atoms treated by a mixture of independent and constrained refinement
S = 1.05Δρmax = 0.71 e Å3
3150 reflectionsΔρmin = 1.42 e Å3
137 parameters
Special details top

Experimental. Numerical integration absorption corrections based on indexed crystal faces were applied using the XPREP routine (Bruker, 1999a)

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

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.4993 (8)0.2871 (3)0.2902 (2)0.0404 (8)
C20.6434 (9)0.3443 (3)0.3357 (2)0.0491 (10)
H20.77710.3830.31790.059*
C30.5861 (9)0.3433 (3)0.4094 (2)0.0482 (10)
H30.67790.38220.4420.058*
C40.3913 (8)0.2838 (3)0.4328 (2)0.0410 (9)
C50.2464 (9)0.2267 (3)0.3873 (2)0.0502 (10)
H50.11570.1870.40530.06*
C60.2991 (9)0.2293 (3)0.3129 (2)0.0481 (10)
H60.20060.19280.27980.058*
N10.5625 (8)0.2874 (3)0.21247 (18)0.0494 (9)
N20.3444 (8)0.2797 (3)0.51204 (17)0.0574 (10)
H2A0.19480.24640.51990.086*
H2B0.31980.33570.5290.086*
H2C0.49030.25450.53490.086*
O10.3995 (8)0.2526 (3)0.16900 (17)0.0692 (10)
O20.7804 (8)0.3222 (3)0.19569 (19)0.0774 (11)
O30.8528 (8)0.3133 (2)0.04409 (18)0.0583 (8)
H3A0.878 (14)0.316 (5)0.0917 (12)0.11 (3)*
H3B0.800 (13)0.366 (3)0.024 (3)0.11 (2)*
I10.33289 (8)0.50637 (2)0.091253 (18)0.06519 (14)
I20.22677 (6)0.531920 (18)0.244438 (16)0.04997 (12)
I30.12058 (7)0.55190 (2)0.402108 (17)0.06257 (14)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.047 (2)0.045 (2)0.0290 (18)0.0061 (17)0.0020 (16)0.0012 (16)
C20.055 (3)0.051 (2)0.041 (2)0.0106 (19)0.003 (2)0.0007 (18)
C30.057 (3)0.055 (2)0.0320 (19)0.003 (2)0.0039 (18)0.0060 (18)
C40.043 (2)0.051 (2)0.0292 (18)0.0095 (17)0.0039 (16)0.0001 (16)
C50.049 (3)0.062 (3)0.041 (2)0.005 (2)0.0075 (19)0.002 (2)
C60.049 (2)0.054 (2)0.041 (2)0.0027 (19)0.0015 (19)0.0070 (19)
N10.057 (2)0.057 (2)0.0341 (18)0.0053 (18)0.0045 (17)0.0046 (16)
N20.056 (2)0.083 (3)0.0341 (18)0.002 (2)0.0071 (16)0.0006 (19)
O10.078 (2)0.090 (3)0.0390 (17)0.009 (2)0.0025 (16)0.0066 (17)
O20.072 (2)0.115 (3)0.0463 (19)0.020 (2)0.0136 (17)0.008 (2)
O30.066 (2)0.067 (2)0.0433 (18)0.0040 (17)0.0108 (16)0.0020 (16)
I10.0854 (3)0.0619 (2)0.0487 (2)0.00069 (17)0.00906 (17)0.00064 (14)
I20.0543 (2)0.04402 (18)0.05185 (19)0.00195 (12)0.00491 (13)0.00021 (12)
I30.0680 (2)0.0673 (2)0.0529 (2)0.00435 (15)0.01033 (16)0.01723 (15)
Geometric parameters (Å, º) top
C1—C21.361 (6)C6—H60.93
C1—C61.365 (6)N1—O11.216 (5)
C1—N11.468 (5)N1—O21.221 (5)
C2—C31.389 (5)N2—H2A0.89
C2—H20.93N2—H2B0.89
C3—C41.366 (6)N2—H2C0.89
C3—H30.93O3—H3A0.88 (2)
C4—C51.362 (6)O3—H3B0.89 (5)
C4—N21.480 (5)I1—I22.8982 (6)
C5—C61.398 (6)I2—I32.9694 (6)
C5—H50.93
C2—C1—C6123.6 (4)C1—C6—C5118.0 (4)
C2—C1—N1118.3 (4)C1—C6—H6121
C6—C1—N1118.1 (4)C5—C6—H6121
C1—C2—C3118.4 (4)O1—N1—O2123.9 (4)
C1—C2—H2120.8O1—N1—C1118.9 (4)
C3—C2—H2120.8O2—N1—C1117.1 (4)
C4—C3—C2118.4 (4)C4—N2—H2A109.5
C4—C3—H3120.8C4—N2—H2B109.5
C2—C3—H3120.8H2A—N2—H2B109.5
C5—C4—C3123.3 (4)C4—N2—H2C109.5
C5—C4—N2119.0 (4)H2A—N2—H2C109.5
C3—C4—N2117.7 (4)H2B—N2—H2C109.5
C4—C5—C6118.4 (4)H3A—O3—H3B114 (6)
C4—C5—H5120.8I1—I2—I3178.209 (14)
C6—C5—H5120.8
C6—C1—C2—C30.7 (7)C2—C1—C6—C52.3 (7)
N1—C1—C2—C3179.3 (4)N1—C1—C6—C5177.7 (4)
C1—C2—C3—C41.2 (7)C4—C5—C6—C12.0 (6)
C2—C3—C4—C51.5 (7)C2—C1—N1—O1164.1 (4)
C2—C3—C4—N2176.4 (4)C6—C1—N1—O115.9 (6)
C3—C4—C5—C60.2 (7)C2—C1—N1—O216.7 (6)
N2—C4—C5—C6178.0 (4)C6—C1—N1—O2163.2 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···O3i0.891.942.824 (5)173
N2—H2B···I3ii0.893.013.731 (4)139
N2—H2C···O1iii0.892.522.922 (5)108
N2—H2C···O3iii0.892.022.860 (5)157
O3—H3A···O20.88 (2)1.98 (3)2.818 (5)158 (6)
O3—H3B···I1iv0.89 (5)2.88 (5)3.722 (3)157 (4)
Symmetry codes: (i) x1, y+1/2, z+1/2; (ii) x, y+1, z+1; (iii) x, y+1/2, z+1/2; (iv) x+1, y+1, z.

Experimental details

Crystal data
Chemical formulaC6H7N2O2+·I3·H2O
Mr537.85
Crystal system, space groupMonoclinic, P21/c
Temperature (K)298
a, b, c (Å)4.8429 (9), 14.701 (3), 18.346 (3)
β (°) 91.916 (3)
V3)1305.4 (4)
Z4
Radiation typeMo Kα
µ (mm1)7.17
Crystal size (mm)0.54 × 0.31 × 0.11
Data collection
DiffractometerBruker SMART 1K CCD area-detector
Absorption correctionIntegration
(XPREP; Bruker, 1999)
Tmin, Tmax0.113, 0.506
No. of measured, independent and
observed [I > 2σ(I)] reflections
8741, 3150, 2461
Rint0.068
(sin θ/λ)max1)0.661
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.081, 1.05
No. of reflections3150
No. of parameters137
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.71, 1.42

Computer programs: SMART-NT (Bruker, 1998), SAINT-Plus (Bruker, 1999), XS in SHELXTL (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 1999), WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···O3i0.891.942.824 (5)173
N2—H2B···I3ii0.893.013.731 (4)139
N2—H2C···O1iii0.892.522.922 (5)108
N2—H2C···O3iii0.892.022.860 (5)157
O3—H3A···O20.88 (2)1.98 (3)2.818 (5)158 (6)
O3—H3B···I1iv0.89 (5)2.88 (5)3.722 (3)157 (4)
Symmetry codes: (i) x1, y+1/2, z+1/2; (ii) x, y+1, z+1; (iii) x, y+1/2, z+1/2; (iv) x+1, y+1, z.
 

Acknowledgements

The University of the Witwatersrand and the National Research Fund (GUN: 2069064) are thanked for the award of a research grant and for providing the infrastructure required to do this work.

References

First citationBrandenburg, K. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
First citationBruker (1998). SMART-NT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationBruker (1999). SAINT-Plus (includes XPREP). Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationEtter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256–262.  CrossRef CAS Web of Science 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 citationLemmerer, A. & Billing, D. G. (2006). Acta Cryst. E62, o1562–o1564.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationParvez, M., Wang, M. & Boorman, P. M. (1996). Acta Cryst. C52, 377–378.  CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationPloug-Sørensen, G. & Andersen, E. K. (1982). Acta Cryst. B38, 671–673.  CSD CrossRef Web of Science IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationShibaeva, R. P. & Yagubskii, E. B. (2004). Chem. Rev. 104, 5347–5378  Web of Science CrossRef PubMed CAS Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationTebbe, K. F. & Loukili, R. (1998). Z. Anorg. Allg. Chem. 624, 1175–1186.  CrossRef CAS Google Scholar

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