The crystal and molecular structure of 1,1'-ferrocenedicarboxylic acid (triclinic modification): neutron and X-ray diffraction studies at 78 K and 298 K

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A neutron diffraction study of the crystal structure of ferrocene

This is the publisher's version, also available electronically from http://scripts.iucr.org/cgi-bin/paper?S0567740879005604.See article for abstract.Research carried out at Brookhaven National Laboratory under contract with the US Department of Energy and supported by its Office of Basic Energy Sciences

A study of the charge density in putrescine diphosphate at 85 K

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A refinement of the crystal structure of quinolinic acid at 100 K with neutron diffraction data

This is the publisher's version, also available electronically from http://scripts.iucr.org/cgi-bin/paper?S0567740878005117.The crystal structure of quinolinic acid (pyridine-2,3-dicarboxylic acid: C7H3N04 ) has been refined, based upon neutron diffraction data measured at 100 K. Crystal data: space group P2l/cm, a — 7-415 (5), b = 12-396 (9), c = 7-826 (6) A, P = 117-05 (4)°, Z = 4. The final unweighted R value based on F2 is 0-048 for all 1643 unique reflections, and bond distances have been determined with precision better than 0-003 A. The major temperature dependence in the cell constants is observed for the b axis, which is perpendicular to the molecular planes. Rigid-body analyses of the thermal parameters determined here at 100 K and those found in a prior study at 297 K indicate that the translational motion changes with temperature more along the b axis than in other directions. Significant differences between the structure at 100 and 297 K are observed in the intramolecular O • • • H • • • O hydrogen bond, where the H atom shifts towards the midpoint of the bond when the crystal is cooled. This temperature effect is discussed in the light of results of the rigid-body thermalmotion analyses

Neutron diffraction study of quinolinic acid recrystallized from D2O: evaluation of temperature and isotope effects in the structure

This is the publisher's version, also available electronically from http://scripts.iucr.org/cgi-bin/paper?S0567740879008591.The structure of quinolinic acid recrystallized from D2 0 (2,3-pyridinedicarboxylic acid; C7H3D2N04 ) has been refined based on neutron diffraction data measured at four temperatures: 35, 80, 100 and 298 K. The principal temperature dependence in cell constants is observed for the b axis, which is perpendicular to the molecular planes. The refined thermal parameters have been extrapolated by a least-squares procedure, to yield values for T = 0 K which provide estimates of the combined effects of static disorder and zero-point motion. The D atom shifts toward the midpoint of the short intramolecular 0 - - - 0 hydrogen bond when the crystal is cooled, just as was found in an earlier study to occur for the H atom in the undeuterated material. At 100 and 298 K, the D atom is displaced significantly further from the bond midpoint than is the H atom at the same temperature. The magnitude of this isotope effect appears to be independent of temperature. The exchangeable protons in the crystal have not been completely replaced by D; refinement of the D scattering lengths indicates the presence of approximately 2-7% H attached to N(l) and 4-4% H in the short hydrogen bond.Research carried out at Brookhaven National Laboratory under contract with the US Department of Energy and supported by its Division of Basic Energy Sciences

Neutron diffraction study of lithium hydrogen phthalate monohydrate: A material with two very short intramolecular O⋅⋅⋅H⋅⋅⋅O hydrogen bonds

Copyright 1985 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in The Journal of Chemical Physics and may be found at http://dx.doi.org/10.1063/1.448550.The structure of lithium hydrogen phthalate monohydrate has been refined based upon neutron diffraction data obtained at three temperatures: 15, 100, and 298 K. All bond distances have been determined with precision better than 0.002 Å. The two crystallographically independent hydrogen phthalate anions in the unit cell both possess very short intramolecular O⋅⋅⋅H⋅⋅⋅O hydrogen bonds with O⋅⋅⋅O≊2.4 Å and ∠O⋅⋅⋅H⋅⋅⋅O≊170°. One of these linkages is very decidedly asymmetric, with O⋅⋅⋅H=1.122(1) Å and H⋅⋅⋅O=1.294(1) Å at 15 K, reflecting the fact that the two O atoms have quite different environments in the crystal. The second O⋅⋅⋅H⋅⋅⋅O bond is more nearly symmetric, with O⋅⋅⋅H=1.195(1) Å and H⋅⋅⋅O=1.205(1) Å at 15 K, but the difference between the two distances is still significant. The asymmetry of the short hydrogen bonds appears somewhat more pronounced at 298 K than at the lower temperatures. A corresponding shift with temperature of the H atom in the short intramolecular hydrogen bond was found previously in 2,3‐pyridinedicarboxylic acid, which has a molecular geometry similar to that found here

Hydrogen bond studies. 85. A very short, asymmetrical, intramolecular hydrogen bond: A neutron diffraction study of pyridine‐2,3‐dicarboxylic acid (C7H5NO4)

This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/60/10/10.1063/1.1680831.A neutron diffraction study of pyridine‐2,3‐dicarboxylic acid (quinolinic acid) has been carried out. The intensities for 3780 reflexions were measured at the Brookhaven High Flux Beam Reactor. The structure was refined to an R(F 2) of 0.054 using starting parameters from a previous x‐ray study. The short intramolecular hydrogen bond [O ··· O: 2.398(3) Å] has no symmetry restriction operating on the hydrogen atom position and is asymmetric. The two O ··· H distances are 1.163(5) and 1.238(5) Å, respectively, and the O–H–O angle is 174.4(4)°. The asymmetry of the bond can be explained by the intramolecular environment. The strain in the molecule caused by the short hydrogen bond results in long carbon‐carbon bonds to the carboxyl groups [1.516(2) and 1.541(2) Å]. The C–O bond lengths [1.219(3), 1.263(2), 1.222(3), and 1.270(2) Å] vary depending on the hydrogen‐bond involvement of the oxygen atoms. The mean C–H distance is 1.087 Å and the N–H distance is 1.036(4) Å. The nitrogen atom is involved in an intermolecular N–H ··· O hydrogen bond [N ··· O: 2.725(2), H ··· O: 1.845(4) Å and angle N–H ··· O: 140.5(2)°]. There are a number of short intermolecular O ··· H–C contacts. The refined neutron scattering length for the nitrogen atom is b̄ N=0.925(4)×10−12 cm

Neutron diffraction study at 37 K of sodium triaqua(ethylenediaminetetraacetato)samarate(III) pentahydrate, Na[Sm(C10H12N2O8)(H2O)3].5H2O

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C-H...O interactions and stacking of water molecules between pyrimidine bases in 5-nitro-1-([beta]-D-ribosyluronic acid)-uracil monohydrate [1-(5-nitro-2,4-dioxopyrimidinyl)-[beta]-D-ribofuranoic acid monohydrate]: a neutron diffraction study at 80 K

This is the publisher's version, also available electronically from http://scripts.iucr.org/cgi-bin/paper?S0567740879006506.See article for abstract.Research carried out at Brookhaven National Laboratory under contract with the US Department of Energy, and supported by its Office of Basic Energy Sciences

Crime and Delinquency in Nevada

Crime and justice system have received much attention from American scholars and politicians in the last than 50 years, with issues in adult criminality, delinquency, and penology emerging at the center stage of criminological inquiry. While scholarly literature now includes many studies focused on different regions and cities, there are no large-scale empirical examinations of crime and delinquency in Nevada. One exception is the Social Health of Nevada report issued in 2006 by University of Nevada, Las Vegas (UNLV) Center for Democratic Culture (CDC)