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ISSN: 2056-9890

1-Methyl-3-n-tetra­decyl­imidazolium bromide monohydrate

aDepartment of Applied Chemistry, College of Science, Nanjing University of Technology, Nanjing 210009, People's Republic of China
*Correspondence e-mail: danbi@njut.edu.cn

(Received 18 September 2009; accepted 28 September 2009; online 3 October 2009)

In the title ionic liquid salt hydrate, C18H35N2+·Br·H2O, the side chain in the cation has an extended conformation. The crystal structure is stabilized primarily by O—H⋯Br hydrogen bonds. C—H⋯O and C—H⋯Br inter­actions are also present.

Related literature

For background to imidazolium ionic liquids, see: Ding et al. (2007[Ding, Y.-S., Zha, M., Zhang, J. & Wang, S.-S. (2007). Coll. Surfaces A Physicochem. Eng. Aspects, 298, 201-205.], 2008[Ding, Y., Tang, H., Zhang, X., Wu, S. & Xiong, R. (2008). J. Appl. Polym. Sci. 109, 1138-1142.]).

[Scheme 1]

Experimental

Crystal data
  • C18H35N2+·Br·H2O

  • Mr = 377.41

  • Triclinic, [P \overline 1]

  • a = 5.5130 (11) Å

  • b = 7.8390 (16) Å

  • c = 25.114 (5) Å

  • α = 94.74 (3)°

  • β = 94.45 (3)°

  • γ = 102.06 (3)°

  • V = 1052.7 (4) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 1.96 mm−1

  • T = 298 K

  • 0.20 × 0.10 × 0.10 mm

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • Absorption correction: ψ scan (North et al., 1968[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.]) Tmin = 0.696, Tmax = 0.828

  • 4277 measured reflections

  • 3843 independent reflections

  • 2593 reflections with I > 2σ(I)

  • Rint = 0.030

  • 3 standard reflections every 200 reflections intensity decay: 1%

Refinement
  • R[F2 > 2σ(F2)] = 0.056

  • wR(F2) = 0.163

  • S = 1.01

  • 3843 reflections

  • 199 parameters

  • H-atom parameters constrained

  • Δρmax = 0.39 e Å−3

  • Δρmin = −0.29 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
OW—HWA⋯Br 0.85 2.57 3.397 (5) 165
OW—HWB⋯Bri 0.85 2.61 3.434 (5) 163
C15—H15A⋯Brii 0.93 2.75 3.659 (5) 166
C17—H17A⋯OW 0.93 2.36 3.217 (7) 153
Symmetry codes: (i) x+1, y, z; (ii) x-1, y-1, z.

Data collection: CAD-4 Software (Enraf–Nonius, 1989[Enraf-Nonius (1989). CAD-4 Software. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, 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: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

The title compound (I) is an example of am imidazolium ionic liquid, which has an influence upon the plasticization and crystallization of polypropylene (Ding et al., 2007 & 2008). Herein, the crystal structure of (I) is described.

The tetradecyl side-side chain in cation, Fig. 1, has an extended conformation. The crystal structure features O-H···Br hydrogen bonding and is further stabilised by C-H···O and C-H···Br interactions, Table 1.

Related literature top

For background to imidazolium ionic liquids, see: Ding et al. (2007, 2008).

Experimental top

Compound (I) was prepared following a modified literature procedure (Ding et al., 2007). 1-Methylimidazole (8.21 g, 0.1 mol) was mixed with tetradecyl bromide (27.7 g, 0.1 mol) in toluene (150 ml) and refluxed for 24 h. The mixture was subsequently cooled to room temperature and filtered. The solids were washed several times with ethyl acetate (600 ml) and the product dried in vacuum (yield: 33.36 g, 92.8%). Colourless crystals were obtained by evaporating a chloroform solution slowly at room temperature for about 5 days.

Refinement top

The H atoms were geometrically placed (O-H = 0.85 Å and C-H = 0.93-0.97Å) and refined as riding with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(O, methyl-C).

Structure description top

The title compound (I) is an example of am imidazolium ionic liquid, which has an influence upon the plasticization and crystallization of polypropylene (Ding et al., 2007 & 2008). Herein, the crystal structure of (I) is described.

The tetradecyl side-side chain in cation, Fig. 1, has an extended conformation. The crystal structure features O-H···Br hydrogen bonding and is further stabilised by C-H···O and C-H···Br interactions, Table 1.

For background to imidazolium ionic liquids, see: Ding et al. (2007, 2008).

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Molecular structure of (I) showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
1-Methyl-3-n-tetradecylimidazolium bromide monohydrate top
Crystal data top
C18H35N2+·Br·H2OZ = 2
Mr = 377.41F(000) = 404
Triclinic, P1Dx = 1.191 Mg m3
Hall symbol: -P 1Melting point: 327 K
a = 5.5130 (11) ÅMo Kα radiation, λ = 0.71073 Å
b = 7.8390 (16) ÅCell parameters from 25 reflections
c = 25.114 (5) Åθ = 10–13°
α = 94.74 (3)°µ = 1.96 mm1
β = 94.45 (3)°T = 298 K
γ = 102.06 (3)°Square, colourless
V = 1052.7 (4) Å30.20 × 0.10 × 0.10 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer
2593 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.030
Graphite monochromatorθmax = 25.3°, θmin = 1.6°
ω/2θ scansh = 06
Absorption correction: ψ scan
(North et al., 1968)
k = 99
Tmin = 0.696, Tmax = 0.828l = 3030
4277 measured reflections3 standard reflections every 200 reflections
3843 independent reflections intensity decay: 1%
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)] = 0.056Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.163H-atom parameters constrained
S = 1.01 w = 1/[σ2(Fo2) + (0.095P)2]
where P = (Fo2 + 2Fc2)/3
3843 reflections(Δ/σ)max = 0.001
199 parametersΔρmax = 0.39 e Å3
0 restraintsΔρmin = 0.29 e Å3
Crystal data top
C18H35N2+·Br·H2Oγ = 102.06 (3)°
Mr = 377.41V = 1052.7 (4) Å3
Triclinic, P1Z = 2
a = 5.5130 (11) ÅMo Kα radiation
b = 7.8390 (16) ŵ = 1.96 mm1
c = 25.114 (5) ÅT = 298 K
α = 94.74 (3)°0.20 × 0.10 × 0.10 mm
β = 94.45 (3)°
Data collection top
Enraf–Nonius CAD-4
diffractometer
2593 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.030
Tmin = 0.696, Tmax = 0.8283 standard reflections every 200 reflections
4277 measured reflections intensity decay: 1%
3843 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0560 restraints
wR(F2) = 0.163H-atom parameters constrained
S = 1.01Δρmax = 0.39 e Å3
3843 reflectionsΔρmin = 0.29 e Å3
199 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Br0.64859 (10)0.68030 (7)0.39439 (2)0.0596 (2)
OW1.0582 (9)0.4268 (6)0.3636 (2)0.116 (2)
HWA0.95260.47930.37660.140*
HWB1.19570.50130.36540.140*
N10.3634 (7)0.0580 (5)0.37818 (15)0.0463 (9)
C11.5342 (12)0.4153 (9)0.2427 (2)0.0812 (18)
H1A1.53760.46900.27860.122*
H1B1.54030.29420.24370.122*
H1C1.67540.47440.22620.122*
N20.5578 (7)0.2140 (5)0.44888 (16)0.0492 (10)
C21.2969 (10)0.4287 (8)0.2104 (2)0.0638 (14)
H2A1.29050.55150.21070.077*
H2B1.15600.37110.22790.077*
C31.2698 (10)0.3493 (7)0.1529 (2)0.0562 (13)
H3A1.41010.40770.13540.067*
H3B1.27820.22690.15270.067*
C41.0317 (9)0.3604 (7)0.1205 (2)0.0547 (13)
H4A0.89110.30280.13810.066*
H4B1.02380.48280.12030.066*
C51.0055 (10)0.2788 (6)0.0629 (2)0.0541 (12)
H5A1.01100.15600.06310.065*
H5B1.14720.33530.04540.065*
C60.7687 (9)0.2923 (7)0.0303 (2)0.0531 (12)
H6A0.62700.23530.04770.064*
H6B0.76290.41510.03030.064*
C70.7432 (9)0.2110 (7)0.02749 (19)0.0525 (12)
H7A0.75200.08870.02750.063*
H7B0.88300.26950.04520.063*
C80.5040 (9)0.2219 (7)0.05954 (19)0.0538 (12)
H8A0.36430.16260.04200.065*
H8B0.49450.34420.05920.065*
C90.4777 (9)0.1422 (7)0.11764 (19)0.0527 (12)
H9A0.48540.01970.11810.063*
H9B0.61770.20090.13520.063*
C100.2402 (9)0.1551 (7)0.1492 (2)0.0538 (12)
H10A0.10050.09650.13140.065*
H10B0.23260.27780.14850.065*
C110.2109 (9)0.0767 (7)0.20710 (19)0.0523 (12)
H11A0.34920.13620.22500.063*
H11B0.21990.04570.20790.063*
C120.0312 (9)0.0890 (7)0.23820 (19)0.0513 (12)
H12A0.03780.21170.23820.062*
H12B0.16910.03260.21960.062*
C130.0672 (9)0.0071 (7)0.29559 (19)0.0500 (12)
H13A0.06470.11640.29620.060*
H13B0.06870.06300.31480.060*
C140.3099 (9)0.0271 (7)0.3228 (2)0.0548 (13)
H14A0.30760.15100.32320.066*
H14B0.44340.02250.30190.066*
C150.2147 (9)0.0269 (7)0.4191 (2)0.0547 (13)
H15A0.05810.04760.41660.066*
C160.3379 (9)0.1246 (6)0.4637 (2)0.0535 (12)
H16A0.28340.12990.49780.064*
C170.5686 (9)0.1733 (6)0.39745 (19)0.0513 (12)
H17A0.69930.21830.37780.062*
C180.7512 (10)0.3378 (7)0.4850 (2)0.0640 (15)
H18A0.88890.38290.46530.096*
H18B0.80760.27820.51380.096*
H18C0.68290.43290.49930.096*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br0.0485 (3)0.0643 (4)0.0633 (4)0.0083 (2)0.0006 (2)0.0054 (2)
OW0.070 (3)0.073 (3)0.201 (6)0.000 (2)0.043 (3)0.010 (3)
N10.039 (2)0.049 (2)0.049 (2)0.0097 (18)0.0032 (19)0.0033 (18)
C10.077 (4)0.103 (5)0.059 (4)0.023 (4)0.014 (3)0.010 (3)
N20.047 (2)0.050 (2)0.047 (3)0.0039 (18)0.0071 (19)0.0045 (18)
C20.059 (3)0.074 (4)0.057 (3)0.020 (3)0.002 (3)0.005 (3)
C30.058 (3)0.061 (3)0.050 (3)0.020 (3)0.003 (3)0.004 (2)
C40.053 (3)0.060 (3)0.052 (3)0.017 (2)0.001 (2)0.001 (2)
C50.055 (3)0.054 (3)0.053 (3)0.015 (2)0.001 (2)0.000 (2)
C60.047 (3)0.062 (3)0.051 (3)0.018 (2)0.002 (2)0.000 (2)
C70.048 (3)0.060 (3)0.050 (3)0.015 (2)0.002 (2)0.001 (2)
C80.049 (3)0.064 (3)0.049 (3)0.021 (2)0.003 (2)0.004 (2)
C90.049 (3)0.058 (3)0.050 (3)0.018 (2)0.004 (2)0.006 (2)
C100.049 (3)0.059 (3)0.052 (3)0.016 (2)0.002 (2)0.003 (2)
C110.049 (3)0.066 (3)0.042 (3)0.020 (2)0.003 (2)0.006 (2)
C120.048 (3)0.058 (3)0.047 (3)0.017 (2)0.004 (2)0.001 (2)
C130.049 (3)0.059 (3)0.041 (3)0.016 (2)0.001 (2)0.001 (2)
C140.051 (3)0.067 (3)0.048 (3)0.021 (2)0.005 (2)0.004 (2)
C150.042 (3)0.062 (3)0.054 (3)0.003 (2)0.002 (2)0.010 (3)
C160.046 (3)0.063 (3)0.049 (3)0.004 (2)0.005 (2)0.006 (2)
C170.045 (3)0.058 (3)0.048 (3)0.004 (2)0.002 (2)0.012 (2)
C180.059 (3)0.060 (3)0.060 (4)0.004 (3)0.016 (3)0.002 (3)
Geometric parameters (Å, º) top
OW—HWA0.8501C7—H7B0.9700
OW—HWB0.8500C8—C91.523 (7)
N1—C171.322 (6)C8—H8A0.9700
N1—C151.370 (6)C8—H8B0.9700
N1—C141.472 (6)C9—C101.503 (7)
C1—C21.512 (8)C9—H9A0.9700
C1—H1A0.9600C9—H9B0.9700
C1—H1B0.9600C10—C111.515 (7)
C1—H1C0.9600C10—H10A0.9700
N2—C171.313 (6)C10—H10B0.9700
N2—C161.363 (6)C11—C121.518 (7)
N2—C181.474 (6)C11—H11A0.9700
C2—C31.507 (7)C11—H11B0.9700
C2—H2A0.9700C12—C131.509 (6)
C2—H2B0.9700C12—H12A0.9700
C3—C41.513 (7)C12—H12B0.9700
C3—H3A0.9700C13—C141.498 (7)
C3—H3B0.9700C13—H13A0.9700
C4—C51.515 (7)C13—H13B0.9700
C4—H4A0.9700C14—H14A0.9700
C4—H4B0.9700C14—H14B0.9700
C5—C61.514 (7)C15—C161.352 (7)
C5—H5A0.9700C15—H15A0.9300
C5—H5B0.9700C16—H16A0.9300
C6—C71.520 (7)C17—H17A0.9300
C6—H6A0.9700C18—H18A0.9600
C6—H6B0.9700C18—H18B0.9600
C7—C81.513 (7)C18—H18C0.9600
C7—H7A0.9700
HWA—OW—HWB107.3C9—C8—H8B108.6
C17—N1—C15108.2 (4)H8A—C8—H8B107.6
C17—N1—C14125.6 (4)C10—C9—C8113.9 (4)
C15—N1—C14126.2 (4)C10—C9—H9A108.8
C2—C1—H1A109.5C8—C9—H9A108.8
C2—C1—H1B109.5C10—C9—H9B108.8
H1A—C1—H1B109.5C8—C9—H9B108.8
C2—C1—H1C109.5H9A—C9—H9B107.7
H1A—C1—H1C109.5C9—C10—C11114.7 (4)
H1B—C1—H1C109.5C9—C10—H10A108.6
C17—N2—C16109.3 (4)C11—C10—H10A108.6
C17—N2—C18125.6 (4)C9—C10—H10B108.6
C16—N2—C18125.1 (4)C11—C10—H10B108.6
C3—C2—C1114.6 (5)H10A—C10—H10B107.6
C3—C2—H2A108.6C10—C11—C12114.0 (4)
C1—C2—H2A108.6C10—C11—H11A108.7
C3—C2—H2B108.6C12—C11—H11A108.7
C1—C2—H2B108.6C10—C11—H11B108.7
H2A—C2—H2B107.6C12—C11—H11B108.7
C2—C3—C4115.0 (4)H11A—C11—H11B107.6
C2—C3—H3A108.5C13—C12—C11114.8 (4)
C4—C3—H3A108.5C13—C12—H12A108.6
C2—C3—H3B108.5C11—C12—H12A108.6
C4—C3—H3B108.5C13—C12—H12B108.6
H3A—C3—H3B107.5C11—C12—H12B108.6
C3—C4—C5114.5 (4)H12A—C12—H12B107.5
C3—C4—H4A108.6C14—C13—C12110.7 (4)
C5—C4—H4A108.6C14—C13—H13A109.5
C3—C4—H4B108.6C12—C13—H13A109.5
C5—C4—H4B108.6C14—C13—H13B109.5
H4A—C4—H4B107.6C12—C13—H13B109.5
C6—C5—C4114.4 (4)H13A—C13—H13B108.1
C6—C5—H5A108.7N1—C14—C13113.6 (4)
C4—C5—H5A108.7N1—C14—H14A108.8
C6—C5—H5B108.7C13—C14—H14A108.8
C4—C5—H5B108.7N1—C14—H14B108.8
H5A—C5—H5B107.6C13—C14—H14B108.8
C5—C6—C7114.3 (4)H14A—C14—H14B107.7
C5—C6—H6A108.7C16—C15—N1107.2 (4)
C7—C6—H6A108.7C16—C15—H15A126.4
C5—C6—H6B108.7N1—C15—H15A126.4
C7—C6—H6B108.7C15—C16—N2106.4 (4)
H6A—C6—H6B107.6C15—C16—H16A126.8
C8—C7—C6114.0 (4)N2—C16—H16A126.8
C8—C7—H7A108.7N2—C17—N1108.9 (4)
C6—C7—H7A108.7N2—C17—H17A125.6
C8—C7—H7B108.7N1—C17—H17A125.6
C6—C7—H7B108.7N2—C18—H18A109.5
H7A—C7—H7B107.6N2—C18—H18B109.5
C7—C8—C9114.4 (4)H18A—C18—H18B109.5
C7—C8—H8A108.6N2—C18—H18C109.5
C9—C8—H8A108.6H18A—C18—H18C109.5
C7—C8—H8B108.6H18B—C18—H18C109.5
C1—C2—C3—C4179.4 (5)C15—N1—C14—C1356.5 (6)
C2—C3—C4—C5179.5 (5)C12—C13—C14—N1177.0 (4)
C3—C4—C5—C6179.2 (4)C17—N1—C15—C160.9 (6)
C4—C5—C6—C7179.8 (4)C14—N1—C15—C16176.8 (4)
C5—C6—C7—C8178.9 (4)N1—C15—C16—N20.5 (6)
C6—C7—C8—C9179.5 (4)C17—N2—C16—C150.2 (6)
C7—C8—C9—C10179.6 (4)C18—N2—C16—C15179.7 (5)
C8—C9—C10—C11179.9 (4)C16—N2—C17—N10.8 (5)
C9—C10—C11—C12179.4 (4)C18—N2—C17—N1179.7 (4)
C10—C11—C12—C13178.4 (4)C15—N1—C17—N21.1 (5)
C11—C12—C13—C14179.6 (4)C14—N1—C17—N2176.7 (4)
C17—N1—C14—C13126.2 (5)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
OW—HWA···Br0.852.573.397 (5)165
OW—HWB···Bri0.852.613.434 (5)163
C15—H15A···Brii0.932.753.659 (5)166
C17—H17A···OW0.932.363.217 (7)153
Symmetry codes: (i) x+1, y, z; (ii) x1, y1, z.

Experimental details

Crystal data
Chemical formulaC18H35N2+·Br·H2O
Mr377.41
Crystal system, space groupTriclinic, P1
Temperature (K)298
a, b, c (Å)5.5130 (11), 7.8390 (16), 25.114 (5)
α, β, γ (°)94.74 (3), 94.45 (3), 102.06 (3)
V3)1052.7 (4)
Z2
Radiation typeMo Kα
µ (mm1)1.96
Crystal size (mm)0.20 × 0.10 × 0.10
Data collection
DiffractometerEnraf–Nonius CAD-4
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.696, 0.828
No. of measured, independent and
observed [I > 2σ(I)] reflections
4277, 3843, 2593
Rint0.030
(sin θ/λ)max1)0.601
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.056, 0.163, 1.01
No. of reflections3843
No. of parameters199
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.39, 0.29

Computer programs: CAD-4 Software (Enraf–Nonius, 1989), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
OW—HWA···Br0.852.573.397 (5)165
OW—HWB···Bri0.852.613.434 (5)163
C15—H15A···Brii0.932.753.659 (5)166
C17—H17A···OW0.932.363.217 (7)153
Symmetry codes: (i) x+1, y, z; (ii) x1, y1, z.
 

Acknowledgements

The authors thank the Centre of Testing and Analysis, Nanjing University, for support.

References

First citationDing, Y., Tang, H., Zhang, X., Wu, S. & Xiong, R. (2008). J. Appl. Polym. Sci. 109, 1138–1142.  Web of Science CrossRef CAS Google Scholar
First citationDing, Y.-S., Zha, M., Zhang, J. & Wang, S.-S. (2007). Coll. Surfaces A Physicochem. Eng. Aspects, 298, 201–205.  Web of Science CrossRef CAS Google Scholar
First citationEnraf–Nonius (1989). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands.  Google Scholar
First citationHarms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.  Google Scholar
First citationNorth, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.  CrossRef IUCr Journals Web of Science Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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