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

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ISSN: 2056-9890

Bis(pyridin-2-ylmeth­yl)ammonium nitrate

aNelson Mandela Metropolitan University, Summerstrand Campus, Department of Chemistry, University Way, Summerstrand, PO Box 77000, Port Elizabeth, 6031, South Africa
*Correspondence e-mail: abubakr.abrahams@nmmu.ac.za

(Received 26 March 2013; accepted 28 March 2013; online 5 April 2013)

In the title compound, C12H14N3+·NO3, the mononitrate of protonated bis­(pyridin-2-ylmeth­yl)amine, the least-squares planes defined by the non-H atoms of the two aromatic moieties inter­sect at an angle of 7.91 (6)°. In the crystal, N—H⋯N, N—H⋯O and C—H⋯N hydrogen bonds, as well as C—H⋯O contacts, connect the entities into a three-dimensional network. The shortest centroid–centroid distance between two aromatic systems is 3.7255 (8) Å and is apparent between the two different aromatic moieties.

Related literature

For the crystal structure of the trinitrate of bis­(pyridin-2-ylmeth­yl)amine, see: Junk et al. (2006[Junk, P. C., Kim, Y., Skelton, B. W. & White, A. H. (2006). Z. Anorg. Allg. Chem. 632, 1340-1350.]). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990[Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256-262.]); 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
  • C12H14N3+·NO3

  • Mr = 262.27

  • Orthorhombic, P b c a

  • a = 11.2236 (2) Å

  • b = 13.4714 (4) Å

  • c = 16.5303 (4) Å

  • V = 2499.34 (11) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 200 K

  • 0.50 × 0.35 × 0.24 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2001[Bruker (2001). SADABS Bruker Inc., Madison, Wisconsin, USA.]) Tmin = 0.923, Tmax = 1.000

  • 12816 measured reflections

  • 3082 independent reflections

  • 2568 reflections with I > 2σ(I)

  • Rint = 0.014

Refinement
  • R[F2 > 2σ(F2)] = 0.041

  • wR(F2) = 0.122

  • S = 1.04

  • 3082 reflections

  • 180 parameters

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

  • Δρmax = 0.29 e Å−3

  • Δρmin = −0.26 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C13—H13⋯N2 0.95 2.61 3.5339 (18) 164
N1—H71⋯O3i 0.893 (18) 2.349 (18) 3.0721 (15) 138.2 (14)
N1—H72⋯O2ii 0.902 (19) 1.982 (19) 2.8831 (15) 176.1 (15)
N1—H72⋯O1ii 0.902 (19) 2.584 (18) 3.2201 (16) 128.1 (14)
N1—H72⋯N2ii 0.902 (19) 2.651 (18) 3.4905 (15) 155.1 (14)
C15—H15⋯O2iii 0.95 2.39 3.1858 (19) 141
C1—H1A⋯O1iv 0.99 2.54 3.5132 (18) 167
C25—H25⋯O1v 0.95 2.53 3.3959 (16) 151
C24—H24⋯O2vi 0.95 2.55 3.4620 (16) 161
Symmetry codes: (i) [x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]; (ii) [-x+{\script{3\over 2}}, -y, z+{\script{1\over 2}}]; (iii) [x-{\script{1\over 2}}, y, -z+{\script{1\over 2}}]; (iv) [x+{\script{1\over 2}}, y, -z+{\script{1\over 2}}]; (v) -x+1, -y, -z+1; (vi) x, y, z+1.

Data collection: APEX2 (Bruker, 2007[Bruker (2007). APEX2 and SAINT Bruker AXS Inc., Madison, Wisconsin,USA.]); cell refinement: SAINT (Bruker, 2007[Bruker (2007). 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, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]) 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 and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

Upon the attempted synthesis of a rare-earth metal coordination compound applying bis(pyridin-2-ylmethyl)amine as an auxilliary ligand, the title compound was unintentionally obtained as the only crystalline reaction product. The crystal structure of the trinitrate salt of bis(pyridin-2-ylmethyl)amine has been reported earlier (Junk et al., 2006).

The twofold-protonated amine-type nitrogen atom is present in a tetrahedral coordination environment. The angles set up by the atoms connected to it cover a range of 107.7 (11)–111.81 (9) °. The least-squares planes defined by the respective non-hydrogen atoms of the two aromatic moieties enclose an angle of 7.91 (6) ° (Fig. 1).

In the crystal, classical hydrogen bonds of the N–H···O type are observed next to C–H···O contacts whose range falls by more than 0.1 Å below the sum of van-der-Waals radii of the atoms participating. In addition, a C–H···N contact involving the nitrate anion is apparent. One of the N–H···O hydrogen bonds shows bifurcation. All the aforementioned contacts are exclusively established between atoms on the cation as well as the anion. Metrical parameters as well as information about the symmetry of these contacts are summarized in Table 1. In total, the entities of the crystal structure are connected to a three-dimensional network. In terms of graph-set analysis (Etter et al., 1990; Bernstein et al., 1995), the descriptor for the C–H···O contacts is DDDD on the unary level while the classical hydrogen bonds necessitate a DDD descriptor on the same level if the bifurcated hydrogen bond is counted as two separate hydrogen bonds. The shortest intercentroid distance between two aromatic systems is measured at 3.7255 (8) Å and is apparent between the two different aromatic moieties (Fig. 2).

The packing of the title compound in the crystal structure is shown in Figure 3.

Related literature top

For the crystal structure of the trinitrate of bis(pyridin-2-ylmethyl)amine, see: Junk et al. (2006). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990); Bernstein et al. (1995).

Experimental top

Lanthanum nitrate was reacted with bis(pyridin-2-ylmethyl)amine in water. Upon free evaporation of the solvent, a crystalline solid was obtained from which irregular-shaped white crystals could be selected.

Refinement top

Carbon-bound H atoms were placed in calculated positions (C–H 0.95 Å for aromatic carbon atoms and C–H 0.99 Å for methylene groups) and were included in the refinement in the riding model approximation, with U(H) set to 1.2Ueq(C). Both nitrogen-bound H atoms were located on a difference Fourier map and refined freely.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); 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, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, with atom labels and anisotropic displacement ellipsoids (drawn at 50% probability level).
[Figure 2] Fig. 2. Intermolecular contacts, viewed approximately along [1 1 0]. Symmetry operators: i x, y, z + 1; ii -x + 1, -y, -z + 1; iii x, -y + 1/2, z + 1/2; iv -x + 3/2, -y, z + 1/2; v x - 1/2, y, -z + 1/2; vi x + 1/2, y, -z + 1/2.
[Figure 3] Fig. 3. Molecular packing of the title compound, viewed along [0 1 0] (anisotropic displacement ellipsoids drawn at 50% probability level).
Bis(pyridin-2-ylmethyl)ammonium nitrate top
Crystal data top
C12H14N3+·NO3F(000) = 1104
Mr = 262.27Dx = 1.394 Mg m3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 5628 reflections
a = 11.2236 (2) Åθ = 2.5–28.2°
b = 13.4714 (4) ŵ = 0.10 mm1
c = 16.5303 (4) ÅT = 200 K
V = 2499.34 (11) Å3Irregular, white
Z = 80.50 × 0.35 × 0.24 mm
Data collection top
Bruker APEXII CCD
diffractometer
3082 independent reflections
Radiation source: fine-focus sealed tube2568 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.014
ϕ and ω scansθmax = 28.3°, θmin = 2.7°
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
h = 814
Tmin = 0.923, Tmax = 1.000k = 1717
12816 measured reflectionsl = 2217
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)] = 0.041Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.122H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.0695P)2 + 0.627P]
where P = (Fo2 + 2Fc2)/3
3082 reflections(Δ/σ)max < 0.001
180 parametersΔρmax = 0.29 e Å3
0 restraintsΔρmin = 0.26 e Å3
Crystal data top
C12H14N3+·NO3V = 2499.34 (11) Å3
Mr = 262.27Z = 8
Orthorhombic, PbcaMo Kα radiation
a = 11.2236 (2) ŵ = 0.10 mm1
b = 13.4714 (4) ÅT = 200 K
c = 16.5303 (4) Å0.50 × 0.35 × 0.24 mm
Data collection top
Bruker APEXII CCD
diffractometer
3082 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
2568 reflections with I > 2σ(I)
Tmin = 0.923, Tmax = 1.000Rint = 0.014
12816 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0410 restraints
wR(F2) = 0.122H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.29 e Å3
3082 reflectionsΔρmin = 0.26 e Å3
180 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.53822 (10)0.03915 (9)0.09542 (8)0.0595 (3)
O20.72195 (8)0.07826 (8)0.08342 (6)0.0438 (3)
O30.58787 (10)0.19315 (8)0.09035 (8)0.0540 (3)
N10.76754 (9)0.13548 (8)0.57810 (6)0.0257 (2)
H710.6936 (16)0.1564 (13)0.5883 (10)0.044 (4)*
H720.7725 (15)0.0688 (14)0.5820 (10)0.044 (4)*
N20.61491 (9)0.10403 (8)0.08911 (6)0.0300 (2)
N110.59551 (10)0.11038 (8)0.46858 (6)0.0345 (2)
N210.71063 (9)0.11508 (7)0.73540 (6)0.0297 (2)
C10.79740 (12)0.16440 (10)0.49410 (7)0.0351 (3)
H1A0.87170.13050.47740.042*
H1B0.81160.23690.49190.042*
C20.84972 (10)0.18126 (9)0.63756 (7)0.0295 (2)
H2A0.84420.25440.63350.035*
H2B0.93260.16170.62460.035*
C110.69911 (12)0.13770 (8)0.43630 (7)0.0313 (3)
C120.71806 (18)0.14422 (10)0.35348 (8)0.0507 (4)
H120.79370.16230.33240.061*
C130.6227 (2)0.12345 (11)0.30224 (9)0.0657 (6)
H130.63150.12910.24530.079*
C140.51552 (19)0.09468 (12)0.33522 (11)0.0598 (5)
H140.44960.07940.30140.072*
C150.50553 (14)0.08849 (11)0.41766 (10)0.0472 (4)
H150.43160.06780.44000.057*
C210.82056 (10)0.14965 (8)0.72268 (7)0.0255 (2)
C220.90516 (11)0.16031 (9)0.78369 (7)0.0309 (3)
H220.98280.18430.77190.037*
C230.87333 (12)0.13503 (9)0.86208 (7)0.0359 (3)
H230.92870.14170.90520.043*
C240.75986 (13)0.10001 (9)0.87633 (7)0.0366 (3)
H240.73530.08290.92950.044*
C250.68233 (11)0.09025 (9)0.81153 (7)0.0346 (3)
H250.60490.06460.82160.041*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0397 (6)0.0467 (6)0.0920 (9)0.0119 (5)0.0001 (5)0.0126 (6)
O20.0298 (5)0.0473 (6)0.0542 (6)0.0045 (4)0.0046 (4)0.0013 (4)
O30.0484 (6)0.0330 (5)0.0805 (8)0.0060 (4)0.0001 (5)0.0027 (5)
N10.0254 (5)0.0290 (5)0.0229 (4)0.0029 (4)0.0008 (3)0.0030 (3)
N20.0309 (5)0.0333 (5)0.0260 (5)0.0003 (4)0.0013 (4)0.0017 (4)
N110.0339 (5)0.0374 (5)0.0322 (5)0.0069 (4)0.0073 (4)0.0051 (4)
N210.0281 (5)0.0325 (5)0.0284 (5)0.0005 (4)0.0000 (4)0.0034 (4)
C10.0395 (6)0.0421 (6)0.0236 (5)0.0092 (5)0.0062 (5)0.0033 (5)
C20.0270 (5)0.0327 (6)0.0287 (6)0.0068 (4)0.0022 (4)0.0014 (4)
C110.0494 (7)0.0219 (5)0.0225 (5)0.0018 (5)0.0017 (5)0.0013 (4)
C120.0989 (13)0.0300 (6)0.0233 (6)0.0127 (7)0.0039 (7)0.0010 (5)
C130.138 (2)0.0328 (7)0.0259 (7)0.0027 (9)0.0235 (9)0.0003 (5)
C140.0905 (14)0.0376 (7)0.0513 (9)0.0206 (8)0.0415 (9)0.0113 (7)
C150.0444 (8)0.0432 (7)0.0542 (9)0.0160 (6)0.0214 (6)0.0127 (6)
C210.0259 (5)0.0244 (5)0.0263 (5)0.0028 (4)0.0025 (4)0.0014 (4)
C220.0289 (5)0.0323 (6)0.0316 (6)0.0044 (4)0.0048 (4)0.0051 (4)
C230.0464 (7)0.0334 (6)0.0278 (6)0.0122 (5)0.0096 (5)0.0052 (5)
C240.0546 (8)0.0303 (6)0.0248 (5)0.0119 (5)0.0031 (5)0.0020 (4)
C250.0367 (7)0.0339 (6)0.0332 (6)0.0018 (5)0.0063 (5)0.0047 (5)
Geometric parameters (Å, º) top
O1—N21.2311 (15)C11—C121.3883 (17)
O2—N21.2541 (14)C12—C131.393 (3)
O3—N21.2385 (14)C12—H120.9500
N1—C11.4806 (14)C13—C141.376 (3)
N1—C21.4822 (14)C13—H130.9500
N1—H710.893 (18)C14—C151.370 (2)
N1—H720.902 (19)C14—H140.9500
N11—C111.3313 (17)C15—H150.9500
N11—C151.3473 (17)C21—C221.3926 (15)
N21—C211.3354 (15)C22—C231.3866 (18)
N21—C251.3403 (15)C22—H220.9500
C1—C111.5030 (18)C23—C241.378 (2)
C1—H1A0.9900C23—H230.9500
C1—H1B0.9900C24—C251.3864 (19)
C2—C211.5061 (16)C24—H240.9500
C2—H2A0.9900C25—H250.9500
C2—H2B0.9900
C1—N1—C2111.81 (9)C11—C12—H12121.0
C1—N1—H71107.7 (11)C13—C12—H12121.0
C2—N1—H71108.8 (11)C14—C13—C12119.15 (15)
C1—N1—H72108.4 (10)C14—C13—H13120.4
C2—N1—H72109.1 (10)C12—C13—H13120.4
H71—N1—H72111.0 (15)C15—C14—C13118.86 (15)
O1—N2—O3121.03 (11)C15—C14—H14120.6
O1—N2—O2118.66 (11)C13—C14—H14120.6
O3—N2—O2120.29 (11)N11—C15—C14123.15 (17)
C11—N11—C15117.70 (13)N11—C15—H15118.4
C21—N21—C25116.99 (10)C14—C15—H15118.4
N1—C1—C11111.53 (10)N21—C21—C22123.50 (11)
N1—C1—H1A109.3N21—C21—C2116.51 (10)
C11—C1—H1A109.3C22—C21—C2119.95 (10)
N1—C1—H1B109.3C23—C22—C21118.41 (12)
C11—C1—H1B109.3C23—C22—H22120.8
H1A—C1—H1B108.0C21—C22—H22120.8
N1—C2—C21111.51 (9)C24—C23—C22118.81 (11)
N1—C2—H2A109.3C24—C23—H23120.6
C21—C2—H2A109.3C22—C23—H23120.6
N1—C2—H2B109.3C23—C24—C25118.70 (11)
C21—C2—H2B109.3C23—C24—H24120.6
H2A—C2—H2B108.0C25—C24—H24120.6
N11—C11—C12123.13 (13)N21—C25—C24123.58 (12)
N11—C11—C1116.90 (10)N21—C25—H25118.2
C12—C11—C1119.95 (13)C24—C25—H25118.2
C11—C12—C13117.98 (17)
C2—N1—C1—C11166.97 (10)C13—C14—C15—N110.8 (2)
C1—N1—C2—C21178.69 (10)C25—N21—C21—C220.28 (17)
C15—N11—C11—C120.18 (18)C25—N21—C21—C2177.56 (10)
C15—N11—C11—C1178.44 (11)N1—C2—C21—N2120.60 (14)
N1—C1—C11—N1111.67 (16)N1—C2—C21—C22161.48 (10)
N1—C1—C11—C12169.68 (11)N21—C21—C22—C230.91 (17)
N11—C11—C12—C131.7 (2)C2—C21—C22—C23176.87 (10)
C1—C11—C12—C13176.91 (12)C21—C22—C23—C240.33 (17)
C11—C12—C13—C141.9 (2)C22—C23—C24—C250.79 (17)
C12—C13—C14—C150.8 (2)C21—N21—C25—C240.94 (18)
C11—N11—C15—C141.1 (2)C23—C24—C25—N211.49 (19)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C13—H13···N20.952.613.5339 (18)164
N1—H71···O3i0.893 (18)2.349 (18)3.0721 (15)138.2 (14)
N1—H72···O2ii0.902 (19)1.982 (19)2.8831 (15)176.1 (15)
N1—H72···O1ii0.902 (19)2.584 (18)3.2201 (16)128.1 (14)
N1—H72···N2ii0.902 (19)2.651 (18)3.4905 (15)155.1 (14)
C15—H15···O2iii0.952.393.1858 (19)141
C1—H1A···O1iv0.992.543.5132 (18)167
C25—H25···O1v0.952.533.3959 (16)151
C24—H24···O2vi0.952.553.4620 (16)161
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x+3/2, y, z+1/2; (iii) x1/2, y, z+1/2; (iv) x+1/2, y, z+1/2; (v) x+1, y, z+1; (vi) x, y, z+1.

Experimental details

Crystal data
Chemical formulaC12H14N3+·NO3
Mr262.27
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)200
a, b, c (Å)11.2236 (2), 13.4714 (4), 16.5303 (4)
V3)2499.34 (11)
Z8
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.50 × 0.35 × 0.24
Data collection
DiffractometerBruker APEXII CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2001)
Tmin, Tmax0.923, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
12816, 3082, 2568
Rint0.014
(sin θ/λ)max1)0.666
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.041, 0.122, 1.04
No. of reflections3082
No. of parameters180
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.29, 0.26

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C13—H13···N20.952.613.5339 (18)164.3
N1—H71···O3i0.893 (18)2.349 (18)3.0721 (15)138.2 (14)
N1—H72···O2ii0.902 (19)1.982 (19)2.8831 (15)176.1 (15)
N1—H72···O1ii0.902 (19)2.584 (18)3.2201 (16)128.1 (14)
N1—H72···N2ii0.902 (19)2.651 (18)3.4905 (15)155.1 (14)
C15—H15···O2iii0.952.393.1858 (19)141.2
C1—H1A···O1iv0.992.543.5132 (18)167.2
C25—H25···O1v0.952.533.3959 (16)151.2
C24—H24···O2vi0.952.553.4620 (16)161.2
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x+3/2, y, z+1/2; (iii) x1/2, y, z+1/2; (iv) x+1/2, y, z+1/2; (v) x+1, y, z+1; (vi) x, y, z+1.
 

Acknowledgements

The authors thank NMMU for the allocation of research facilities.

References

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
First citationBruker (2001). SADABS Bruker Inc., Madison, Wisconsin, USA.
First citationBruker (2007). APEX2 and SAINT Bruker AXS Inc., Madison, Wisconsin,USA.
First citationEtter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256–262.  CrossRef CAS Web of Science IUCr Journals
First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals
First citationJunk, P. C., Kim, Y., Skelton, B. W. & White, A. H. (2006). Z. Anorg. Allg. Chem. 632, 1340–1350.  Web of Science CSD CrossRef CAS
First citationMacrae, 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.  Web of Science CrossRef CAS 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

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