The power of the state-of-the-art neutron powder diffractometer suite at the Institut Laue-Langevin for investigating the structure of nondeuterated materials is presented using gypsum, CaSO4·2H2O, as a reference material. It is shown that flexible modern neutron powder diffraction instruments at reactor-based sources can yield data with sufficient counting statistics above the incoherent scattering contribution to perform unconstrained refinements in relatively short time periods (from minutes to a few hours, depending on the sample size and the instrument choice), without the requirement for significant changes to the standard operational modes of the instruments. The results are critically compared with previous literature from single-crystal and powder X-ray and neutron measurements on deuterated and nondeuterated gypsum.
Supporting information
| Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889809043210/cg5117sup1.cif Contains datablocks MULTI_16_publ, MULTI_16_overall, MULTI_16_phase_1, MULTI_16_p_01, MULTI_16_p_02, I2A_publ, I2A_overall, I2A_phase_1, I2A_p_01, I2A_p_02 |
| Portable Document Format (PDF) file https://doi.org/10.1107/S0021889809043210/cg5117sup2.pdf characterization information (powder X-ray diffraction, TGA) |
Data collection: SMART (Bruker, 2007); cell refinement: SAINT-Plus (Bruker, 2007); data reduction: SAINT-Plus (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: X-SEED (Barbour, 2001).
1,2-Di-4-pyridylethane
N,
N'-dioxide–acetic acid (1/2)
top
Crystal data top
C12H12N2O2·2C2H4O2 | Z = 1 |
Mr = 336.34 | F(000) = 178 |
Triclinic, P1 | Dx = 1.370 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.1109 (6) Å | Cell parameters from 3794 reflections |
b = 7.1562 (6) Å | θ = 3.2–30.5° |
c = 9.2888 (7) Å | µ = 0.11 mm−1 |
α = 73.719 (1)° | T = 173 K |
β = 87.508 (1)° | Block, colorless |
γ = 64.424 (1)° | 0.55 × 0.45 × 0.37 mm |
V = 407.62 (6) Å3 | |
Data collection top
Bruker SMART APEX CCD diffractometer | 2446 independent reflections |
Radiation source: fine-focus sealed tube | 2228 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.011 |
ω scans | θmax = 30.5°, θmin = 2.3° |
Absorption correction: multi-scan (SADABS; Bruker, 2001) | h = −10→10 |
Tmin = 0.944, Tmax = 0.962 | k = −10→9 |
4857 measured reflections | l = −13→13 |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.044 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.133 | H-atom parameters constrained |
S = 1.09 | w = 1/[σ2(Fo2) + (0.0796P)2 + 0.0824P] where P = (Fo2 + 2Fc2)/3 |
2446 reflections | (Δ/σ)max = 0.001 |
114 parameters | Δρmax = 0.39 e Å−3 |
0 restraints | Δρmin = −0.25 e Å−3 |
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 | x | y | z | Uiso*/Ueq | |
O1 | 0.13750 (10) | 0.89616 (12) | 0.18453 (8) | 0.02574 (15) | |
O2 | 0.65037 (13) | 1.15878 (12) | 0.46617 (9) | 0.03371 (18) | |
O3 | 0.86230 (12) | 0.87364 (12) | 0.65134 (8) | 0.02891 (16) | |
H3 | 0.8470 | 0.9693 | 0.6925 | 0.043* | |
N1 | 0.32388 (11) | 0.79711 (12) | 0.13545 (9) | 0.019 | |
C1 | 0.48607 (14) | 0.64120 (15) | 0.23478 (10) | 0.022 | |
H1 | 0.4674 | 0.6045 | 0.3391 | 0.026* | |
C2 | 0.67866 (13) | 0.53522 (15) | 0.18518 (10) | 0.02148 (17) | |
H2 | 0.7919 | 0.4267 | 0.2558 | 0.026* | |
C3 | 0.70835 (13) | 0.58611 (14) | 0.03222 (10) | 0.01794 (15) | |
C4 | 0.53728 (13) | 0.74729 (14) | −0.06672 (10) | 0.01899 (16) | |
H4 | 0.5520 | 0.7860 | −0.1717 | 0.023* | |
C5 | 0.34614 (13) | 0.85159 (14) | −0.01355 (10) | 0.01970 (16) | |
H5 | 0.2308 | 0.9614 | −0.0819 | 0.024* | |
C6 | 0.91767 (13) | 0.46745 (14) | −0.02202 (10) | 0.01940 (16) | |
H6A | 0.9022 | 0.5004 | −0.1329 | 0.023* | |
H6B | 0.9662 | 0.3095 | 0.0222 | 0.023* | |
C7 | 0.76154 (14) | 0.96654 (16) | 0.51521 (10) | 0.02359 (18) | |
C8 | 0.80145 (17) | 0.80587 (18) | 0.42910 (12) | 0.0301 (2) | |
H8A | 0.6925 | 0.8686 | 0.3456 | 0.045* | |
H8B | 0.7993 | 0.6741 | 0.4963 | 0.045* | |
H8C | 0.9386 | 0.7700 | 0.3892 | 0.045* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0129 (3) | 0.0322 (4) | 0.0298 (3) | −0.0051 (3) | 0.0056 (2) | −0.0140 (3) |
O2 | 0.0348 (4) | 0.0244 (4) | 0.0278 (4) | −0.0039 (3) | 0.0014 (3) | −0.0014 (3) |
O3 | 0.0253 (3) | 0.0244 (3) | 0.0276 (4) | −0.0027 (3) | −0.0033 (3) | −0.0063 (3) |
N1 | 0.012 | 0.020 | 0.024 | −0.005 | 0.003 | −0.008 |
C1 | 0.017 | 0.024 | 0.021 | −0.006 | 0.001 | −0.006 |
C2 | 0.0149 (4) | 0.0216 (4) | 0.0235 (4) | −0.0041 (3) | 0.0004 (3) | −0.0061 (3) |
C3 | 0.0131 (3) | 0.0171 (4) | 0.0241 (4) | −0.0063 (3) | 0.0025 (3) | −0.0073 (3) |
C4 | 0.0157 (4) | 0.0184 (4) | 0.0214 (4) | −0.0069 (3) | 0.0024 (3) | −0.0046 (3) |
C5 | 0.0148 (3) | 0.0184 (4) | 0.0233 (4) | −0.0056 (3) | 0.0010 (3) | −0.0047 (3) |
C6 | 0.0136 (3) | 0.0195 (4) | 0.0260 (4) | −0.0064 (3) | 0.0038 (3) | −0.0096 (3) |
C7 | 0.0177 (4) | 0.0260 (4) | 0.0224 (4) | −0.0078 (3) | 0.0058 (3) | −0.0036 (3) |
C8 | 0.0292 (5) | 0.0314 (5) | 0.0272 (5) | −0.0109 (4) | 0.0061 (4) | −0.0093 (4) |
Geometric parameters (Å, º) top
O1—N1 | 1.3358 (9) | C3—C6 | 1.5079 (11) |
O2—C7 | 1.2107 (12) | C4—C5 | 1.3859 (11) |
O3—C7 | 1.3231 (12) | C4—H4 | 0.9500 |
O3—H3 | 0.8400 | C5—H5 | 0.9500 |
N1—C5 | 1.3506 (12) | C6—C6i | 1.5410 (17) |
N1—C1 | 1.3530 (12) | C6—H6A | 0.9900 |
C1—C2 | 1.3811 (12) | C6—H6B | 0.9900 |
C1—H1 | 0.9500 | C7—C8 | 1.5021 (14) |
C2—C3 | 1.3950 (13) | C8—H8A | 0.9800 |
C2—H2 | 0.9500 | C8—H8B | 0.9800 |
C3—C4 | 1.3951 (12) | C8—H8C | 0.9800 |
| | | |
O1—N1—C1 | 119.76 (8) | C1—C2—H2 | 119.7 |
C5—N1—C1 | 120.99 (8) | C2—C1—H1 | 119.8 |
O1—N1—C5 | 119.24 (7) | C3—C2—H2 | 119.7 |
N1—C1—C2 | 120.31 (8) | C3—C4—H4 | 119.6 |
N1—C5—C4 | 120.00 (8) | C3—C6—H6A | 109.3 |
C1—C2—C3 | 120.58 (8) | C3—C6—H6B | 109.3 |
C2—C3—C4 | 117.43 (8) | C4—C5—H5 | 120.0 |
C3—C4—C5 | 120.70 (8) | C5—C4—H4 | 119.6 |
C4—C3—C6 | 122.07 (8) | C6i—C6—H6A | 109.3 |
C2—C3—C6 | 120.50 (8) | C6i—C6—H6B | 109.3 |
C3—C6—C6i | 111.43 (8) | C7—C8—H8A | 109.5 |
O2—C7—O3 | 123.73 (10) | C7—C8—H8B | 109.5 |
O2—C7—C8 | 124.14 (9) | C7—C8—H8C | 109.5 |
O3—C7—C8 | 112.13 (8) | H6A—C6—H6B | 108.0 |
N1—C1—H1 | 119.8 | H8A—C8—H8B | 109.5 |
N1—C5—H5 | 120.0 | H8A—C8—H8C | 109.5 |
C7—O3—H3 | 109.5 | H8B—C8—H8C | 109.5 |
Symmetry code: (i) −x+2, −y+1, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3···O1ii | 0.84 | 1.72 | 2.5393 (11) | 164 |
C1—H1···O2ii | 0.95 | 2.68 | 3.3915 (12) | 132 |
C2—H2···O3iii | 0.95 | 2.45 | 3.3489 (11) | 158 |
C5—H5···O1iv | 0.95 | 2.48 | 3.3341 (12) | 149 |
C6—H6B···O1v | 0.99 | 2.66 | 3.6309 (12) | 168 |
C8—H8C···O1vi | 0.98 | 2.52 | 3.3655 (13) | 145 |
Symmetry codes: (ii) −x+1, −y+2, −z+1; (iii) −x+2, −y+1, −z+1; (iv) −x, −y+2, −z; (v) x+1, y−1, z; (vi) x+1, y, z. |