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

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Bis{2-amino-2-oxo-N-[(1E)-1-(pyridin-2-yl-κN)ethyl­­idene]acetohydrazidato-κ2N′,O1}nickel(II)

aDépartement de Chimie, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Senegal, and bCentre de Recherche de Gif sur Yvette, Institut de Chimie des Substances Naturelles, UPR2301-CNRS, 1 Avenue la Terrasse, 91198 Gif sur Yvette cédex, France
*Correspondence e-mail: mlgayeastou@yahoo.fr

(Received 29 March 2012; accepted 31 March 2012; online 6 April 2012)

In the title compound, [Ni(C9H9N4O2)2], the NiII ion is situated on a twofold rotation axis and is coordinated by two O and four N atoms from two tridentate {2-amino-2-oxo-N-[(1E)-1-(pyridin-2-yl-κN)ethyl­idene]acetohydrazidate ligands in a distorted octa­hedral geometry. In the crystal, N—H⋯O and N—H⋯N hydrogen bonds link the mol­ecules into columns in [001]. The porous crystal packing is further stabilized via ππ inter­actions between the pyridine rings of neighbouring mol­ecules [centroid–centroid distance = 3.746 (3) Å] with voids of 270 Å3.

Related literature

For the structures of related nickel complexes, see: Dieng et al. (2004[Dieng, M., Gaye, M., Sall, A. S. & Welter, R. (2004). Z. Kristallogr. 219, 15-16.]); Tamboura et al. (2009[Tamboura, F. B., Gaye, M., Sall, A. S., Barry, A. H. & Bah, Y. (2009). Acta Cryst. E65, m160-m161.]); Mikuriya et al. (1996[Mikuriya, M., Nakadera, K. & Kotera, T. (1996). Bull. Chem. Soc. Jpn, 69, 399-405.]).

[Scheme 1]

Experimental

Crystal data
  • [Ni(C9H9N4O2)2]

  • Mr = 469.11

  • Monoclinic, C 2/c

  • a = 16.703 (3) Å

  • b = 17.878 (4) Å

  • c = 8.929 (2) Å

  • β = 114.915 (5)°

  • V = 2418.2 (9) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.84 mm−1

  • T = 293 K

  • 0.21 × 0.14 × 0.13 mm

Data collection
  • Nonius KappaCCD diffractometer

  • Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]) Tmin = 0.778, Tmax = 0.897

  • 6288 measured reflections

  • 1781 independent reflections

  • 1285 reflections with I > 2σ(I)

  • Rint = 0.046

  • θmax = 23.5°

Refinement
  • R[F2 > 2σ(F2)] = 0.051

  • wR(F2) = 0.137

  • S = 1.04

  • 1777 reflections

  • 142 parameters

  • H-atom parameters constrained

  • Δρmax = 0.33 e Å−3

  • Δρmin = −0.30 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N4—H4A⋯O2i 0.86 2.22 2.976 (5) 147
N4—H4B⋯N3ii 0.86 2.25 3.074 (5) 160
Symmetry codes: (i) [x, -y+1, z+{\script{1\over 2}}]; (ii) [-x+1, y, -z+{\script{3\over 2}}].

Data collection: DENZO (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]) and COLLECT (Nonius, 1999[Nonius (1999). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: DENZO and COLLECT; data reduction: SCALEPACK (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]); 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.]) and CRYSTALBUILDER (Welter, 2006[Welter, R. (2006). Acta Cryst. A62, s252.]); molecular graphics: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Comment top

In the title compound (Fig. 1), the NiII ion is situated on a twofold rotational and adopts a distorted octahedral geometry. The coordination of the hydrazones to Ni center results in the formation of two five-membered chelating rings. In the two rings, the Ni–Npyridyl bond lengths of 2.094 (3) Å are larger than those for Ni–Niminol bonds [1.980 (3) Å]. The Ni–O1 involving the hydrazonic oxygen have the metal-ligand distance of 2.074 (3) Å. The Ni—N and Ni—O bond distances are similar to those observed in other mononuclear NiII complexes with similar tridentate ligands (Dieng et al., 2004; Tamboura et al., 2009). The following bond C6–N2 is not altered in the complex and remains with double bond character. The bond C8–N3 which was simple in character becomes a double bond after deprotonation of the N–H function. The Nimino–Ni–O1 and Npyridyl–Ni–Nimino angles are 78.25 (13)° and 92.04 (13)° respectively. The deviation from 90° of the bond angles involving the chelation observed is presumably due to the formation of five-membered ring (Mikuriya et al., 1996).

In the crystal structure, the intermolecular hydrogen-bonding network involving the acetamide groups and also the N3 atom (Table 1), propagates parallel to the crystallographic c axis (Fig.2). This contributes to display a double inverted X molecular pattern in the ab plane stabilized by ππ stacking interactions between adjacent pyridine rings with the centroid-centroid distance of 3.746 (3) Å.

Related literature top

For the structures of related nickel complexes, see: Dieng et al. (2004); Tamboura et al. (2009); Mikuriya et al. (1996).

Experimental top

2-Amino-2-oxo-N'-(1-(pyridin-2-yl)ethylidene)acetohydrazide (0.206 g, 1 mmol) was dissolved in 10 ml of ethanol and the LiOH (0.042 g, 2 mmol) was added with thorough shaking. To the resulting solution, Ni(CH3COO)2.4H2O (0.2489 g, 1 mmol) was added. Immediate change of the colour was observed. The mixture was stirred at room temperature during 2 h. The solution was filtered off and concentrated to tenth. Crystals that separated from the brown solution were filtered off and recrystallized in ethanol. On standing for three weeks, suitable X-rays crystals were obtained. Yield: 73.5%. Anal. Calc. for [C18H18N8O4Ni] (%): C, 46.09; H, 3.87; N, 23.89. Found: C, 46.06; H, 3.85; N, 23.87. Selected IR data (cm-1, KBr pellet): 3214, 1728, 1645, 1585, 1459, 768.

Refinement top

All H atoms were located in difference maps. They were then treated as riding in geometrically idealized positions, with C—H = 0.93 (aryl), or 0.96 Å(CH3) and N—H = 0.86 Å, and with Uiso(H)=kUeq(C,N), where k = 1.5 for the methyl groups, and 1.2 for all other H atoms. Four low-resolution reflections were omitted due to beamstop shading (OMIT instruction in SHELX97-L)). Infinite cylindrical channels of 8 Å diameters ran through the crystal packing along the crystallographic c axis at positions x=0, y=1/2, z and x=1/2, y=0, z accounting for voids of 270 Å3 per unit cell but no solvent contribution to the X-ray diffraction was found.

Computing details top

Data collection: DENZO (Otwinowski & Minor, 1997) and COLLECT (Nonius, 1999); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT (Nonius, 1999); data reduction: SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) and CRYSTALBUILDER (Welter, 2006); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. An ORTEP view of the title compound, showing the atom-numbering scheme [symmetry code: (a) -x + 1, y, -z + 1/2]. Displacement ellipsoids are plotted at the 30% probability level.
[Figure 2] Fig. 2. A portion of the crystal packing viewed down the a axis and showing hydrogen bonds as cyan lines.
Bis{2-amino-2-oxo-N-[(1E)-1-(pyridin-2- yl-κN)ethylidene]acetohydrazidato-κ2N',O1}nickel(II) top
Crystal data top
[Ni(C9H9N4O2)2]F(000) = 968
Mr = 469.11Dx = 1.289 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71070 Å
Hall symbol: -C 2ycCell parameters from 1780 reflections
a = 16.703 (3) Åθ = 0.4–23.5°
b = 17.878 (4) ŵ = 0.84 mm1
c = 8.929 (2) ÅT = 293 K
β = 114.915 (5)°Block, brown
V = 2418.2 (9) Å30.21 × 0.14 × 0.13 mm
Z = 4
Data collection top
Nonius KappaCCD
diffractometer
1781 independent reflections
Radiation source: fine-focus sealed tube, Nonius Kappa CCD1285 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.046
Detector resolution: 9 pixels mm-1θmax = 23.5°, θmin = 2.3°
phi and ω scansh = 1818
Absorption correction: multi-scan
(SCALEPACK; Otwinowski & Minor, 1997)
k = 1820
Tmin = 0.778, Tmax = 0.897l = 99
6288 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)] = 0.051Hydrogen site location: difference Fourier map
wR(F2) = 0.137H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0757P)2]
where P = (Fo2 + 2Fc2)/3
1777 reflections(Δ/σ)max < 0.001
142 parametersΔρmax = 0.33 e Å3
0 restraintsΔρmin = 0.30 e Å3
Crystal data top
[Ni(C9H9N4O2)2]V = 2418.2 (9) Å3
Mr = 469.11Z = 4
Monoclinic, C2/cMo Kα radiation
a = 16.703 (3) ŵ = 0.84 mm1
b = 17.878 (4) ÅT = 293 K
c = 8.929 (2) Å0.21 × 0.14 × 0.13 mm
β = 114.915 (5)°
Data collection top
Nonius KappaCCD
diffractometer
1781 independent reflections
Absorption correction: multi-scan
(SCALEPACK; Otwinowski & Minor, 1997)
1285 reflections with I > 2σ(I)
Tmin = 0.778, Tmax = 0.897Rint = 0.046
6288 measured reflectionsθmax = 23.5°
Refinement top
R[F2 > 2σ(F2)] = 0.0510 restraints
wR(F2) = 0.137H-atom parameters constrained
S = 1.04Δρmax = 0.33 e Å3
1777 reflectionsΔρmin = 0.30 e Å3
142 parameters
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. Five low-resolution reflections were omitted due to beamstop shading (OMIT instruction in SHELX97-L).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Ni10.50000.30602 (4)0.25000.0392 (3)
O10.41866 (19)0.38561 (16)0.2833 (3)0.0451 (8)
O20.3304 (2)0.4879 (2)0.3757 (4)0.0722 (11)
N10.5999 (2)0.22513 (19)0.3236 (4)0.0438 (9)
N20.5383 (2)0.30400 (18)0.4922 (4)0.0368 (8)
N30.4949 (2)0.35081 (19)0.5577 (4)0.0406 (9)
N40.3876 (3)0.4413 (2)0.6353 (4)0.0572 (11)
H4A0.35760.47100.66760.069*
H4B0.42320.40940.70310.069*
C10.6314 (3)0.1867 (3)0.2321 (6)0.0567 (13)
H10.60640.19480.11870.068*
C20.6990 (4)0.1356 (3)0.2970 (7)0.0708 (16)
H20.71890.10970.22900.085*
C30.7360 (4)0.1241 (3)0.4635 (7)0.0733 (17)
H30.78220.09020.51090.088*
C40.7050 (3)0.1624 (3)0.5594 (6)0.0631 (14)
H40.73020.15500.67310.076*
C50.6359 (3)0.2127 (2)0.4885 (5)0.0475 (12)
C60.5976 (3)0.2576 (2)0.5825 (5)0.0453 (11)
C70.6273 (4)0.2469 (3)0.7638 (5)0.0713 (17)
H7A0.59350.27860.80200.107*
H7B0.68870.25950.82020.107*
H7C0.61890.19560.78560.107*
C80.4349 (3)0.3894 (2)0.4339 (5)0.0369 (10)
C90.3792 (3)0.4445 (3)0.4806 (5)0.0482 (12)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ni10.0409 (5)0.0462 (5)0.0311 (5)0.0000.0158 (4)0.000
O10.0491 (19)0.0503 (18)0.0330 (16)0.0100 (15)0.0144 (14)0.0013 (14)
O20.091 (3)0.080 (3)0.052 (2)0.042 (2)0.036 (2)0.0173 (19)
N10.044 (2)0.047 (2)0.040 (2)0.0055 (18)0.0176 (18)0.0014 (18)
N20.037 (2)0.0394 (19)0.0332 (19)0.0013 (18)0.0144 (16)0.0023 (17)
N30.049 (2)0.045 (2)0.0321 (19)0.0077 (18)0.0208 (18)0.0014 (17)
N40.064 (3)0.069 (3)0.042 (2)0.023 (2)0.026 (2)0.002 (2)
C10.058 (3)0.065 (3)0.052 (3)0.008 (3)0.028 (3)0.009 (3)
C20.069 (4)0.075 (4)0.065 (4)0.019 (3)0.025 (3)0.019 (3)
C30.062 (4)0.072 (4)0.072 (4)0.032 (3)0.016 (3)0.009 (3)
C40.058 (3)0.067 (3)0.051 (3)0.020 (3)0.010 (3)0.001 (3)
C50.045 (3)0.051 (3)0.043 (3)0.004 (2)0.015 (2)0.001 (2)
C60.043 (3)0.053 (3)0.036 (2)0.004 (2)0.013 (2)0.004 (2)
C70.082 (4)0.091 (4)0.036 (3)0.034 (3)0.020 (3)0.012 (3)
C80.041 (3)0.039 (2)0.031 (2)0.001 (2)0.016 (2)0.001 (2)
C90.050 (3)0.057 (3)0.038 (3)0.008 (2)0.018 (2)0.002 (2)
Geometric parameters (Å, º) top
Ni1—N2i1.980 (3)N4—H4B0.8600
Ni1—N21.980 (3)C1—C21.376 (6)
Ni1—O1i2.074 (3)C1—H10.9300
Ni1—O12.074 (3)C2—C31.364 (7)
Ni1—N1i2.094 (3)C2—H20.9300
Ni1—N12.094 (3)C3—C41.359 (7)
O1—C81.257 (5)C3—H30.9300
O2—C91.225 (5)C4—C51.388 (6)
N1—C11.333 (6)C4—H40.9300
N1—C51.354 (5)C5—C61.487 (6)
N2—C61.283 (5)C6—C71.492 (6)
N2—N31.387 (5)C7—H7A0.9600
N3—C81.330 (5)C7—H7B0.9600
N4—C91.329 (5)C7—H7C0.9600
N4—H4A0.8600C8—C91.528 (6)
N2i—Ni1—N2177.92 (19)C2—C1—H1118.3
N2i—Ni1—O1i77.63 (12)C3—C2—C1118.3 (5)
N2—Ni1—O1i103.84 (12)C3—C2—H2120.8
N2i—Ni1—O1103.84 (12)C1—C2—H2120.8
N2—Ni1—O177.63 (12)C4—C3—C2119.5 (5)
O1i—Ni1—O193.34 (17)C4—C3—H3120.3
N2i—Ni1—N1i78.26 (13)C2—C3—H3120.3
N2—Ni1—N1i100.27 (13)C3—C4—C5120.3 (5)
O1i—Ni1—N1i155.88 (12)C3—C4—H4119.9
O1—Ni1—N1i92.02 (13)C5—C4—H4119.9
N2i—Ni1—N1100.27 (13)N1—C5—C4120.4 (4)
N2—Ni1—N178.26 (13)N1—C5—C6115.2 (4)
O1i—Ni1—N192.02 (13)C4—C5—C6124.4 (4)
O1—Ni1—N1155.88 (12)N2—C6—C5113.3 (4)
N1i—Ni1—N192.6 (2)N2—C6—C7125.5 (4)
C8—O1—Ni1109.4 (2)C5—C6—C7121.2 (4)
C1—N1—C5118.2 (4)C6—C7—H7A109.5
C1—N1—Ni1129.2 (3)C6—C7—H7B109.5
C5—N1—Ni1112.6 (3)H7A—C7—H7B109.5
C6—N2—N3121.8 (3)C6—C7—H7C109.5
C6—N2—Ni1120.5 (3)H7A—C7—H7C109.5
N3—N2—Ni1117.6 (2)H7B—C7—H7C109.5
C8—N3—N2107.9 (3)O1—C8—N3127.4 (4)
C9—N4—H4A120.0O1—C8—C9116.4 (4)
C9—N4—H4B120.0N3—C8—C9116.2 (3)
H4A—N4—H4B120.0O2—C9—N4124.6 (4)
N1—C1—C2123.4 (5)O2—C9—C8119.0 (4)
N1—C1—H1118.3N4—C9—C8116.4 (4)
N2i—Ni1—O1—C8177.3 (3)Ni1—N1—C1—C2178.8 (4)
N2—Ni1—O1—C81.2 (3)N1—C1—C2—C30.4 (8)
O1i—Ni1—O1—C8104.6 (3)C1—C2—C3—C40.5 (9)
N1i—Ni1—O1—C898.9 (3)C2—C3—C4—C50.4 (9)
N1—Ni1—O1—C82.1 (5)C1—N1—C5—C41.5 (7)
N2i—Ni1—N1—C13.4 (4)Ni1—N1—C5—C4178.0 (4)
N2—Ni1—N1—C1178.1 (4)C1—N1—C5—C6179.9 (4)
O1i—Ni1—N1—C174.4 (4)Ni1—N1—C5—C60.4 (5)
O1—Ni1—N1—C1177.2 (3)C3—C4—C5—N11.4 (8)
N1i—Ni1—N1—C181.9 (4)C3—C4—C5—C6179.6 (5)
N2i—Ni1—N1—C5177.3 (3)N3—N2—C6—C5179.9 (3)
N2—Ni1—N1—C51.2 (3)Ni1—N2—C6—C54.1 (5)
O1i—Ni1—N1—C5104.9 (3)N3—N2—C6—C70.5 (7)
O1—Ni1—N1—C52.1 (5)Ni1—N2—C6—C7175.3 (4)
N1i—Ni1—N1—C598.7 (3)N1—C5—C6—N22.8 (6)
O1i—Ni1—N2—C692.3 (3)C4—C5—C6—N2175.5 (4)
O1—Ni1—N2—C6177.3 (3)N1—C5—C6—C7176.7 (4)
N1i—Ni1—N2—C687.5 (3)C4—C5—C6—C75.0 (7)
N1—Ni1—N2—C63.1 (3)Ni1—O1—C8—N31.1 (5)
O1i—Ni1—N2—N391.7 (3)Ni1—O1—C8—C9178.8 (3)
O1—Ni1—N2—N31.3 (3)N2—N3—C8—O10.1 (6)
N1i—Ni1—N2—N388.5 (3)N2—N3—C8—C9179.8 (3)
N1—Ni1—N2—N3179.1 (3)O1—C8—C9—O28.8 (6)
C6—N2—N3—C8177.0 (4)N3—C8—C9—O2171.4 (4)
Ni1—N2—N3—C81.1 (4)O1—C8—C9—N4171.0 (4)
C5—N1—C1—C20.6 (7)N3—C8—C9—N48.9 (6)
Symmetry code: (i) x+1, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N4—H4A···O2ii0.862.222.976 (5)147
N4—H4B···N3iii0.862.253.074 (5)160
Symmetry codes: (ii) x, y+1, z+1/2; (iii) x+1, y, z+3/2.

Experimental details

Crystal data
Chemical formula[Ni(C9H9N4O2)2]
Mr469.11
Crystal system, space groupMonoclinic, C2/c
Temperature (K)293
a, b, c (Å)16.703 (3), 17.878 (4), 8.929 (2)
β (°) 114.915 (5)
V3)2418.2 (9)
Z4
Radiation typeMo Kα
µ (mm1)0.84
Crystal size (mm)0.21 × 0.14 × 0.13
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correctionMulti-scan
(SCALEPACK; Otwinowski & Minor, 1997)
Tmin, Tmax0.778, 0.897
No. of measured, independent and
observed [I > 2σ(I)] reflections
6288, 1781, 1285
Rint0.046
θmax (°)23.5
(sin θ/λ)max1)0.561
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.051, 0.137, 1.04
No. of reflections1777
No. of parameters142
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.33, 0.30

Computer programs: DENZO (Otwinowski & Minor, 1997) and COLLECT (Nonius, 1999), SCALEPACK (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008) and CRYSTALBUILDER (Welter, 2006), PLATON (Spek, 2009), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N4—H4A···O2i0.862.222.976 (5)147.2
N4—H4B···N3ii0.862.253.074 (5)159.9
Symmetry codes: (i) x, y+1, z+1/2; (ii) x+1, y, z+3/2.
 

References

First citationDieng, M., Gaye, M., Sall, A. S. & Welter, R. (2004). Z. Kristallogr. 219, 15–16.  CAS
First citationMikuriya, M., Nakadera, K. & Kotera, T. (1996). Bull. Chem. Soc. Jpn, 69, 399–405.  CrossRef CAS Web of Science
First citationNonius (1999). COLLECT. Nonius BV, Delft, The Netherlands.
First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.
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 citationTamboura, F. B., Gaye, M., Sall, A. S., Barry, A. H. & Bah, Y. (2009). Acta Cryst. E65, m160–m161.  Web of Science CSD CrossRef IUCr Journals
First citationWelter, R. (2006). Acta Cryst. A62, s252.  CrossRef IUCr Journals
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals

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