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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

cif

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

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Portable Document Format (PDF) file https://doi.org/10.1107/S0021889809043210/cg5117sup2.pdf
characterization information (powder X-ray diffraction, TGA)

Computing details top

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
C12H12N2O2·2C2H4O2Z = 1
Mr = 336.34F(000) = 178
Triclinic, P1Dx = 1.370 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.1109 (6) ÅCell parameters from 3794 reflections
b = 7.1562 (6) Åθ = 3.2–30.5°
c = 9.2888 (7) ŵ = 0.11 mm1
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 tube2228 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.011
ω scansθmax = 30.5°, θmin = 2.3°
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
h = 1010
Tmin = 0.944, Tmax = 0.962k = 109
4857 measured reflectionsl = 1313
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)] = 0.044Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.133H-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 parametersΔρmax = 0.39 e Å3
0 restraintsΔρmin = 0.25 e Å3
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
O10.13750 (10)0.89616 (12)0.18453 (8)0.02574 (15)
O20.65037 (13)1.15878 (12)0.46617 (9)0.03371 (18)
O30.86230 (12)0.87364 (12)0.65134 (8)0.02891 (16)
H30.84700.96930.69250.043*
N10.32388 (11)0.79711 (12)0.13545 (9)0.019
C10.48607 (14)0.64120 (15)0.23478 (10)0.022
H10.46740.60450.33910.026*
C20.67866 (13)0.53522 (15)0.18518 (10)0.02148 (17)
H20.79190.42670.25580.026*
C30.70835 (13)0.58611 (14)0.03222 (10)0.01794 (15)
C40.53728 (13)0.74729 (14)0.06672 (10)0.01899 (16)
H40.55200.78600.17170.023*
C50.34614 (13)0.85159 (14)0.01355 (10)0.01970 (16)
H50.23080.96140.08190.024*
C60.91767 (13)0.46745 (14)0.02202 (10)0.01940 (16)
H6A0.90220.50040.13290.023*
H6B0.96620.30950.02220.023*
C70.76154 (14)0.96654 (16)0.51521 (10)0.02359 (18)
C80.80145 (17)0.80587 (18)0.42910 (12)0.0301 (2)
H8A0.69250.86860.34560.045*
H8B0.79930.67410.49630.045*
H8C0.93860.77000.38920.045*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0129 (3)0.0322 (4)0.0298 (3)0.0051 (3)0.0056 (2)0.0140 (3)
O20.0348 (4)0.0244 (4)0.0278 (4)0.0039 (3)0.0014 (3)0.0014 (3)
O30.0253 (3)0.0244 (3)0.0276 (4)0.0027 (3)0.0033 (3)0.0063 (3)
N10.0120.0200.0240.0050.0030.008
C10.0170.0240.0210.0060.0010.006
C20.0149 (4)0.0216 (4)0.0235 (4)0.0041 (3)0.0004 (3)0.0061 (3)
C30.0131 (3)0.0171 (4)0.0241 (4)0.0063 (3)0.0025 (3)0.0073 (3)
C40.0157 (4)0.0184 (4)0.0214 (4)0.0069 (3)0.0024 (3)0.0046 (3)
C50.0148 (3)0.0184 (4)0.0233 (4)0.0056 (3)0.0010 (3)0.0047 (3)
C60.0136 (3)0.0195 (4)0.0260 (4)0.0064 (3)0.0038 (3)0.0096 (3)
C70.0177 (4)0.0260 (4)0.0224 (4)0.0078 (3)0.0058 (3)0.0036 (3)
C80.0292 (5)0.0314 (5)0.0272 (5)0.0109 (4)0.0061 (4)0.0093 (4)
Geometric parameters (Å, º) top
O1—N11.3358 (9)C3—C61.5079 (11)
O2—C71.2107 (12)C4—C51.3859 (11)
O3—C71.3231 (12)C4—H40.9500
O3—H30.8400C5—H50.9500
N1—C51.3506 (12)C6—C6i1.5410 (17)
N1—C11.3530 (12)C6—H6A0.9900
C1—C21.3811 (12)C6—H6B0.9900
C1—H10.9500C7—C81.5021 (14)
C2—C31.3950 (13)C8—H8A0.9800
C2—H20.9500C8—H8B0.9800
C3—C41.3951 (12)C8—H8C0.9800
O1—N1—C1119.76 (8)C1—C2—H2119.7
C5—N1—C1120.99 (8)C2—C1—H1119.8
O1—N1—C5119.24 (7)C3—C2—H2119.7
N1—C1—C2120.31 (8)C3—C4—H4119.6
N1—C5—C4120.00 (8)C3—C6—H6A109.3
C1—C2—C3120.58 (8)C3—C6—H6B109.3
C2—C3—C4117.43 (8)C4—C5—H5120.0
C3—C4—C5120.70 (8)C5—C4—H4119.6
C4—C3—C6122.07 (8)C6i—C6—H6A109.3
C2—C3—C6120.50 (8)C6i—C6—H6B109.3
C3—C6—C6i111.43 (8)C7—C8—H8A109.5
O2—C7—O3123.73 (10)C7—C8—H8B109.5
O2—C7—C8124.14 (9)C7—C8—H8C109.5
O3—C7—C8112.13 (8)H6A—C6—H6B108.0
N1—C1—H1119.8H8A—C8—H8B109.5
N1—C5—H5120.0H8A—C8—H8C109.5
C7—O3—H3109.5H8B—C8—H8C109.5
Symmetry code: (i) x+2, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3···O1ii0.841.722.5393 (11)164
C1—H1···O2ii0.952.683.3915 (12)132
C2—H2···O3iii0.952.453.3489 (11)158
C5—H5···O1iv0.952.483.3341 (12)149
C6—H6B···O1v0.992.663.6309 (12)168
C8—H8C···O1vi0.982.523.3655 (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, y1, z; (vi) x+1, y, z.
 

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