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

Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296

Di­phenyl­mercury, redetermined at 120 K: sheets built from a single C—H⋯π(arene) hydrogen bond

aSchool of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland, bDepartment of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen AB24 3UE, Scotland, and cInstituto de Química, Departamento de Química Inorgânica, Universidade Federal do Rio de Janeiro, 21945-970 Rio de Janeiro, RJ, Brazil
*Correspondence e-mail: cg@st-andrews.ac.uk

(Received 21 December 2004; accepted 22 December 2004; online 31 January 2005)

At 120 K, the molecules of the title compound, [Hg(C6H5)2], lie across centres of inversion in space group P21/n and are linked by a single C—H⋯π(arene) hydrogen bond into (101) sheets. The same supramolecular structure is found at 298 K.

Comment

The structure of diphenyl­mercury, (I)[link], was first successfully analysed only in 1977 (Grdenić et al., 1977[Grdenić, D., Kamenar, B. & Nagl, A. (1977). Acta Cryst. B33, 587-589.]), despite numerous earlier attempts (Kitaigorodsky & Grdenić, 1948[Kitaigorodsky, A. I. & Grdenić, D. (1948). Izv. Akad. Nauk SSSR Otd. Khim. Nauk, p. 262.]; Ziólkowska, 1962[Ziólkowska, B. (1962). Rocz. Chem. 36, 1341-1347.]; Ziólkowska et al., 1964[Ziólkowska, B., Myasnikova, R. M. & Kitaigorodsky, A. I. (1964). Zh. Strukt. Khim. 5, 737-742.]), which had been hampered by a combination of inadequate absorption corrections and the occurrence of twinning. Using diffraction data collected at ambient temperature, an R value of 0.023 was achieved with 725 unweighted data and with H atoms included in the calculations with C—H distances in the range 0.93–1.02 Å (Grdenić et al., 1977[Grdenić, D., Kamenar, B. & Nagl, A. (1977). Acta Cryst. B33, 587-589.]). The structure consisted of nearly planar centrosymmetric molecules; although a number of fairly short C⋯C, C⋯H and H⋯H intermolecular contacts were recorded, the consequences of these were not analysed. Our reanalysis, using PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]), of the published structure using atomic coordinates retrieved from the Cambridge Structural Database (Allen, 2002[Allen, F. H. (2002). Acta Cryst. B58, 380-388.]; refcode DIPHHG11) found no direction-specific intermolecular interactions.

[Scheme 1]

We have now reinvestigated the structure of (I) using a larger data set collected at 120 K; in addition, we collected a data set at 298 K, and the same phase was found. Although, for the sake of convenience and the much lower β angle, we have chosen to refine the structure in space group P21/n, rather than the alternative P21/c, as employed by Grdenić et al. (1977[Grdenić, D., Kamenar, B. & Nagl, A. (1977). Acta Cryst. B33, 587-589.]), we also solved the structure in P21/c. It was evident, from both the cell dimensions and the atom coordinates in P21/c that the same phase was employed in this study as in the earlier one. The structure of (I) determined at 120 K has better precision than that reported at ambient temperatures. Thus, the s.u. values on the Hg—C and C—C distances (Table 1[link]) are less than half of those reported previously (0.007 Å for Hg—C and 0.010–0.014 Å for C—C). Despite the larger data set used here, at 120 K, the conventional R value is significantly lower than the previous ambient-temperature value (0.023).

We find at 120 K, centrosymmetric molecules (Fig. 1[link]) with an interplanar spacing of 0.222 (4) Å, consistent with the structure previously reported at ambient temperature. However, these molecules are linked into sheets by a single nearly linear C—H⋯π(arene) hydrogen bond (Table 2[link]). With the reference molecule centred at ([{1\over 2}], [{1\over 2}], [{1\over 2}]), atoms C6 at (x, y, z) and (1 − x, 1 − y, 1 − z) act as hydrogen-bond donors to the aryl rings at ([{3\over 2}] − x, −[{1\over 2}] + y, [{1\over 2}] − z) and (−[{1\over 2}] + x, [{3\over 2}] − y, [{1\over 2}] + z), respectively, which form parts of the molecules centred at (1, 0, 0) and (0, 1, 1), respectively. Similarly, the aryl rings at (x, y, z) and (1 − x, 1 − y, 1 − z) accept hydrogen bonds from atoms C6 at ([{3\over 2}] − x, [{1\over 2}] + y, [{1\over 2}] − z) and (−[{1\over 2}] + x, [{1\over 2}] − y, [{1\over 2}] + z), respectively, which form parts of the molecules centred at (1, 1, 0) and (0, 0, 1). In this way, the molecules are linked into (101) sheets (Fig. 2[link]), although there are no direction-specific interactions between adjacent sheets.

We find precisely the same supramolecular aggregation at 298 K, and the question then arises why this aggregation is not apparent from the coordinates reported by Grdenić et al. (1977[Grdenić, D., Kamenar, B. & Nagl, A. (1977). Acta Cryst. B33, 587-589.]). The explanation appears to lie in the location of the H atoms in the earlier structure. The authors stated that `the H atoms were included in the structure-factor calculations with the isotropic thermal parameters of the bonded C atoms, but the parameters were not refined' (Grdenić et al., 1977[Grdenić, D., Kamenar, B. & Nagl, A. (1977). Acta Cryst. B33, 587-589.]); however, at no point did the authors specify how the H atoms were actually located or what constraints were applied to their positions during the refinement. In fact, analysis of their H-atom coordinates shows that many of these atoms are significantly displaced from the plane of the aryl ring; in particular, the two calculated C—C—C—H torsion angles for the H atom bonded to atom C6 are 168 and −169°. In addition, the two exocyclic C—C—H angles at atom C6 are 116 and 123°, and it seems probable that the erroneous location of the H atom bonded to atom C6 has previously obscured the occurrence of the C—H⋯π(arene) hydrogen bond.

[Figure 1]
Figure 1
The molecule of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and atoms labelled with the suffix A are at the symmetry position (1 − x, 1 − y, 1 − z).
[Figure 2]
Figure 2
Part of the crystal structure of (I), showing a (101) sheet formed from the action of a C—H⋯π(arene) hydrogen bond. Hg atoms marked with an asterisk (*), a hash (#) or an ampersand (&) are at the positions (1, 0, 0), ([{1\over 2}], −[{1\over 2}], [{1\over 2}]) and (0, 0, 1), respectively. For the sake of clarity, H atoms not involved in the motif shown have been omitted.

Experimental

The title compound was isolated from the reaction between mercury(II) chloride and methyl­triphenyl­tin(IV) (2:1 molar ratio) in ethanol. Crystals suitable for single-crystal X-ray diffraction were grown by slow evaporation of a solution in ethanol.

Crystal data
  • [Hg(C6H5)2]

  • Mr = 354.79

  • Monoclinic, P21/n

  • a = 5.6222 (3) Å

  • b = 8.0912 (4) Å

  • c = 10.5852 (5) Å

  • β = 95.485 (3)°

  • V = 479.32 (4) Å3

  • Z = 2

  • Dx = 2.458 Mg m−3

  • Mo Kα radiation

  • Cell parameters from 1098 reflections

  • θ = 3.2–27.5°

  • μ = 16.00 mm−1

  • T = 120 (2) K

  • Plate, colourless

  • 0.28 × 0.12 × 0.04 mm

Data collection
  • Nonius KappaCCD diffractometer

  • φ and ω scans

  • Absorption correction: multi-scan(SADABS; Sheldrick, 2003[Sheldrick, G. M. (2003). SADABS. Version 2.10. University of Göttingen, Germany.])Tmin = 0.088, Tmax = 0.527

  • 7117 measured reflections

  • 1098 independent reflections

  • 837 reflections with I > 2σ(I)

  • Rint = 0.034

  • θmax = 27.5°

  • h = −7 → 7

  • k = −10 → 10

  • l = −13 → 13

Refinement
  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.017

  • wR(F2) = 0.045

  • S = 1.09

  • 1098 reflections

  • 62 parameters

  • H-atom parameters constrained

  • w = 1/[σ2(Fo2) + (0.0209P)2 + 0.2975P] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max < 0.001

  • Δρmax = 0.71 e Å−3

  • Δρmin = −0.87 e Å−3

  • Extinction correction: SHELXL97

  • Extinction coefficient: 0.0133 (8)

Table 1
Selected geometric parameters (Å)

Hg1—C1 2.088 (3)
C1—C2 1.393 (5)
C2—C3 1.384 (5)
C3—C4 1.402 (5)
C4—C5 1.383 (5)
C5—C6 1.398 (5)
C6—C1 1.400 (5)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C6—H6⋯Cgi 0.95 2.84 3.759 (4) 164
Symmetry code: (i) [-x+{\script{3\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}].
Note: Cg is the centroid of the C1–C6 ring.

All H atoms were located from difference maps and then treated as riding, with C—H = 0.95 Å and Uiso(H) = 1.2Ueq(C).

Data collection, cell refinement and data reduction: COLLECT (Hooft, 1999[Hooft, R. (1999). COLLECT. Nonius BV, Delft, The Netherlands.]) and 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.]); structure solution: OSCAIL (McArdle, 2003[McArdle, P. (2003). OSCAIL for Windows. Version 10. Crystallography Centre, Chemistry Department, NUI Galway, Ireland.]) and SHELXS97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); structure refinement: OSCAIL and SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); molecular graphics: PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999[Ferguson, G. (1999). PRPKAPPA. University of Guelph, Canada.]).

Supporting information


Comment top

The structure of diphenylmercury, (I), was first successfully analysed only in 1977 (Grdenić et al., 1977), despite numerous earlier attempts (Kitaigorodsky & Grdenić, 1948; Ziólkowska, 1962; Ziólkowska et al., 1964), which had been hampered by a combination of inadequate absorption corrections and the occurrence of twinning. Using diffraction data collected at ambient temperature, an R value of 0.023 was achieved with 725 unweighted data and with H atoms included in the calculations with C—H distances in the range 0.93–1.02 Å (Grdenić et al., 1977). The structure consisted of nearly planar centrosymmetric molecules; although a number of fairly short C···C, C···H and H···H intermolecular contacts were recorded, the consequences of these were not analysed. Our reanalysis, using PLATON (Spek, 2003), of the published structure using atomic coordinates retrieved from the Cambridge Structural Database (Allen, 2002: refcode DIPHHG11) found no direction-specific intermolecular interactions.

We have now reinvestigated the structure of (I) using a somewhat larger data set collected at 120 K; in addition, we collected a data set at 298 K, and the same phase was found. Although, for the sake of convenience and the much lower β angle, we have chosen to refine the structure in space group P21/n, rather than the alternative P21/c as employed earlier (Grdenić et al., 1977), we also solved the structure in P21/c. It was evident, both from the cell dimensions and from the atom coordinates in P21/c, that the same phase was employed in this study as in the earlier one. The structure of (I) determined at 120 K has rather better precision than that reported at ambient temperatures. Thus the s.u. values on the Hg—C and C—C distances (Table 1) are less than half of those reported previously (0.007 Å for Hg—C and 0.010 − 0.014 Å for C—C). Despite the larger data set used here, at 120 K the conventional R value is significantly lower than the previous ambient-temperature value (0.023).

We find at 120 K centrosymmetric molecules with an interplanar spacing of 0.222 (4) Å, consistent with the structure previously reported at ambient temperature. However, these molecules are linked into sheets by a single nearly linear C—H···π(arene) hydrogen bond (Table 2). With the reference molecule centred at (1/2, 1/2, 1/2), atoms C6 at (x, y, z) and (1 − x, 1 − y, 1 − z) act as hydrogen-bond donors to the aryl rings at (1.5 − x, −1/2 + y, 1/2 − z) and (−1/2 + x, 1.5 − y, 1/2 + z), respectively, which form parts of the molecules centred at (1, 0, 0) and (0, 1, 1), respectively. Similarly, the aryl rings at (x, y, z) and (1 − x, 1 − y, 1 − z) accept hydrogen-bonds from atoms C6 at (1.5 − x, 1/2 + y, 1/2 − z) and (−1/2 + x, 1/2 − y, 1/2 + z), respectively, which form parts of the molecules centred at (1, 1, 0) and (0, 0, 1), respectively. In this way, the molecules are linked into (101) sheets (Fig. 2), although there are no direction-specific interactions between adjacent sheets.

We find precisely the same supramolecular aggregation at 298 K, and the question then arises why this aggregation is not apparent from the coordinates reported by Grdenić et al. (1977). The explanation appears to lie in the location of the H atoms in the earlier structure. The authors stated that `the H atoms were included in the structure factor calculations with the isotropic thermal parameters of the bonded C atoms, but the parameters were not refined' (Grdenić et al., 1977); however, at no point did the authors specify how the H atoms were actually located, or what constraints were applied to their positions during the refinement. In fact, analysis of their H-atom coordinates shows that many of these atoms are significantly displaced from the plane of the aryl ring; in particular, the two calculated C—C—C—H torsion angles for the H atom bonded to atom C6 are 168 and −169°. In addition, the two exocyclic C—C—H angles at atom C6 are 116 and 123°, and it seems probable that the erroneous location of the H atom bonded to atom C6 has previously obscured the occurrence of the C—H···π(arene) hydrogen bond.

Experimental top

The title compound was isolated from the reaction between mercury(II) chloride and methyltriphenyltin(IV) (2:1 molar ratio) in ethanol. Crystals suitable for single-crystal X-ray diffraction were grown by slow evaporation of a solution in ethanol.

Refinement top

The space group P21/n was uniquely assigned from the systematic absences. All H atoms were located from difference maps and then treated as riding atoms, with C—H distances of 0.95 Å, and with Uiso(H) values of 1.2Ueq(C).

Computing details top

Data collection: COLLECT (Hooft, 1999); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: OSCAIL (McArdle, 2003) and SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: OSCAIL and SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).

Figures top
[Figure 1] Fig. 1. The molecule of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level, and atoms labelled with the suffix A are at the symmetry position (1 − x, 1 − y, 1 − z).
[Figure 2] Fig. 2. Part of the crystal structure of (I), showing a (101) sheet formed from the action of a C—H···π(arene) hydrogen bond. Hg atoms marked with an asterisk (*), a hash (#) or an ampersand (&) are at the positions (1, 0, 0), (1/2, −0.5,1/2) and (0, 0, 1), respectively.
Diphenylmercury top
Crystal data top
[Hg(C6H5)2]F(000) = 324
Mr = 354.79Dx = 2.458 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 1098 reflections
a = 5.6222 (3) Åθ = 3.2–27.5°
b = 8.0912 (4) ŵ = 16.00 mm1
c = 10.5852 (5) ÅT = 120 K
β = 95.485 (3)°Plate, colourless
V = 479.32 (4) Å30.28 × 0.12 × 0.04 mm
Z = 2
Data collection top
Nonius KappaCCD
diffractometer
1098 independent reflections
Radiation source: Bruker-Nonius FR91 rotating anode837 reflections with I > 2σ(I)
Graphite (Nonius, 1997) monochromatorRint = 0.034
Detector resolution: 9.091 pixels mm-1θmax = 27.5°, θmin = 3.2°
ϕ and ω scansh = 77
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
k = 1010
Tmin = 0.088, Tmax = 0.527l = 1313
7117 measured reflections
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)] = 0.017H-atom parameters constrained
wR(F2) = 0.045 w = 1/[σ2(Fo2) + (0.0209P)2 + 0.2975P]
where P = (Fo2 + 2Fc2)/3
S = 1.09(Δ/σ)max < 0.001
1098 reflectionsΔρmax = 0.71 e Å3
62 parametersΔρmin = 0.87 e Å3
0 restraintsExtinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0133 (8)
Crystal data top
[Hg(C6H5)2]V = 479.32 (4) Å3
Mr = 354.79Z = 2
Monoclinic, P21/nMo Kα radiation
a = 5.6222 (3) ŵ = 16.00 mm1
b = 8.0912 (4) ÅT = 120 K
c = 10.5852 (5) Å0.28 × 0.12 × 0.04 mm
β = 95.485 (3)°
Data collection top
Nonius KappaCCD
diffractometer
1098 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
837 reflections with I > 2σ(I)
Tmin = 0.088, Tmax = 0.527Rint = 0.034
7117 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0170 restraints
wR(F2) = 0.045H-atom parameters constrained
S = 1.09Δρmax = 0.71 e Å3
1098 reflectionsΔρmin = 0.87 e Å3
62 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Hg10.50000.50000.50000.01832 (12)
C10.7711 (6)0.6208 (5)0.4146 (3)0.0195 (8)
C20.9167 (7)0.7397 (5)0.4779 (3)0.0190 (7)
C31.1047 (6)0.8126 (4)0.4233 (3)0.0191 (8)
C41.1532 (6)0.7684 (5)0.3003 (3)0.0186 (7)
C51.0092 (6)0.6516 (4)0.2355 (3)0.0202 (8)
C60.8206 (6)0.5779 (5)0.2917 (3)0.0213 (8)
H20.88590.77190.56110.023*
H31.20120.89280.46930.023*
H41.28230.81750.26230.022*
H51.03880.62110.15180.024*
H60.72460.49740.24570.026*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Hg10.01561 (15)0.01792 (15)0.02234 (16)0.00019 (7)0.00656 (8)0.00452 (8)
C10.0155 (17)0.0186 (19)0.0247 (18)0.0043 (15)0.0032 (14)0.0057 (15)
C20.0231 (18)0.0172 (19)0.0174 (17)0.0030 (16)0.0052 (14)0.0007 (14)
C30.0176 (18)0.0173 (19)0.0225 (18)0.0028 (14)0.0025 (14)0.0002 (15)
C40.0173 (17)0.0189 (19)0.0198 (17)0.0013 (14)0.0024 (13)0.0039 (15)
C50.0230 (18)0.023 (2)0.0154 (16)0.0014 (15)0.0048 (14)0.0021 (15)
C60.0216 (19)0.019 (2)0.0230 (19)0.0015 (17)0.0017 (14)0.0004 (16)
Geometric parameters (Å, º) top
Hg1—C12.088 (3)C6—C11.400 (5)
C1—C21.393 (5)C2—H20.95
C2—C31.384 (5)C3—H30.95
C3—C41.402 (5)C4—H40.95
C4—C51.383 (5)C5—H50.95
C5—C61.398 (5)C6—H60.95
C2—C1—C6117.3 (3)C5—C4—C3118.6 (3)
C2—C1—Hg1122.3 (3)C5—C4—H4120.7
C6—C1—Hg1120.3 (3)C3—C4—H4120.7
C3—C2—C1122.0 (3)C4—C5—C6120.8 (3)
C3—C2—H2119.0C4—C5—H5119.6
C1—C2—H2119.0C6—C5—H5119.6
C2—C3—C4120.2 (3)C5—C6—C1121.0 (4)
C2—C3—H3119.9C5—C6—H6119.5
C4—C3—H3119.9C1—C6—H6119.5
C6—C1—C2—C30.6 (5)C3—C4—C5—C60.6 (5)
Hg1—C1—C2—C3176.3 (3)C4—C5—C6—C10.4 (5)
C1—C2—C3—C40.4 (6)C2—C1—C6—C50.2 (5)
C2—C3—C4—C50.2 (5)Hg1—C1—C6—C5176.8 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C6—H6···Cgi0.952.843.759 (4)164
Symmetry code: (i) x+3/2, y1/2, z+1/2.

Experimental details

Crystal data
Chemical formula[Hg(C6H5)2]
Mr354.79
Crystal system, space groupMonoclinic, P21/n
Temperature (K)120
a, b, c (Å)5.6222 (3), 8.0912 (4), 10.5852 (5)
β (°) 95.485 (3)
V3)479.32 (4)
Z2
Radiation typeMo Kα
µ (mm1)16.00
Crystal size (mm)0.28 × 0.12 × 0.04
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2003)
Tmin, Tmax0.088, 0.527
No. of measured, independent and
observed [I > 2σ(I)] reflections
7117, 1098, 837
Rint0.034
(sin θ/λ)max1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.017, 0.045, 1.09
No. of reflections1098
No. of parameters62
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.71, 0.87

Computer programs: COLLECT (Hooft, 1999), DENZO (Otwinowski & Minor, 1997) and COLLECT, DENZO and COLLECT, OSCAIL (McArdle, 2003) and SHELXS97 (Sheldrick, 1997), OSCAIL and SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2003), SHELXL97 and PRPKAPPA (Ferguson, 1999).

Selected bond lengths (Å) top
Hg1—C12.088 (3)C4—C51.383 (5)
C1—C21.393 (5)C5—C61.398 (5)
C2—C31.384 (5)C6—C11.400 (5)
C3—C41.402 (5)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C6—H6···Cgi0.952.843.759 (4)164
Symmetry code: (i) x+3/2, y1/2, z+1/2.
 

Acknowledgements

X-ray data were collected at the EPSRC X-ray Crystallographic Service, University of Southampton, England; the authors thank the staff for all their help and advice. JLW thanks CNPq and FAPERJ for financial support.

References

First citationAllen, F. H. (2002). Acta Cryst. B58, 380–388.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationFerguson, G. (1999). PRPKAPPA. University of Guelph, Canada.  Google Scholar
First citationGrdenić, D., Kamenar, B. & Nagl, A. (1977). Acta Cryst. B33, 587–589.  CSD CrossRef IUCr Journals Web of Science Google Scholar
First citationHooft, R. (1999). COLLECT. Nonius BV, Delft, The Netherlands.  Google Scholar
First citationKitaigorodsky, A. I. & Grdenić, D. (1948). Izv. Akad. Nauk SSSR Otd. Khim. Nauk, p. 262.  Google Scholar
First citationMcArdle, P. (2003). OSCAIL for Windows. Version 10. Crystallography Centre, Chemistry Department, NUI Galway, Ireland.  Google Scholar
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.  Google Scholar
First citationSheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.  Google Scholar
First citationSheldrick, G. M. (2003). SADABS. Version 2.10. University of Göttingen, Germany.  Google Scholar
First citationSpek, A. L. (2003). J. Appl. Cryst. 36, 7–13.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationZiólkowska, B. (1962). Rocz. Chem. 36, 1341–1347.  CAS Google Scholar
First citationZiólkowska, B., Myasnikova, R. M. & Kitaigorodsky, A. I. (1964). Zh. Strukt. Khim. 5, 737–742.  CAS Google Scholar

© International Union of Crystallography. Prior permission is not required to reproduce short quotations, tables and figures from this article, provided the original authors and source are cited. For more information, click here.

Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296
Follow Acta Cryst. C
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds