Single-crystal, time-of-flight, neutron-diffraction structure of hydrogen cis-diacetyltetracarbonylrhenate, [cis-(OC)4Re(CH3CO)2]H: a metallaacetylacetone molecule

Schultz, Arthur J.; Srinivasan, K.; Teller, Raymond G.; Williams, Jack M.; Lukehart, C. M.

doi:10.1021/ja00316a031

Cited by 112 publications

(96 citation statements)

References 1 publication

(1 reference statement)

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“…Numeric absorption corrections were applied using polyhedral models of the individual crystals, and detector efficiencies were accounted for using the AN-VRED3 program. 27 The final reduced dataset was refined to models using SHELXL. 28 Unless otherwise indicated, reciprocal space vectors are indexed using the C2/c monoclinic space group where H is parallel to the long-axis of the unit cell and K is parallel to the unique axis.…”

Section: 24mentioning

confidence: 99%

Doping-driven structural distortion in the bilayer iridate (Sr1−xLax)3Ir2O

et al. 2017

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Neutron single crystal diffraction and rotational anisotropy optical second harmonic generation data are presented resolving the nature of the structural distortion realized in electron-doped (Sr1−xLax)3Ir2O7 with x = 0.035 and x = 0.071. Once electrons are introduced into the bilayer spin-orbit assisted Mott insulator Sr3Ir2O7, previous studies have identified the appearance of a low temperature structural distortion and have suggested the presence of a competing electronic instability in the phase diagram of this material. Our measurements resolve a lowering of the structural symmetry from monoclinic C2/c to monoclinic P 21/c and the creation of two unique Ir sites within the chemical unit cell as the lattice distorts below a critical temperature TS. Details regarding the modifications to oxygen octahedral rotations and tilting through the transition are discussed as well as the evolution of the low temperature distorted lattice as a function of carrier substitution.

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Section: 24mentioning

confidence: 99%

Doping-driven structural distortion in the bilayer iridate (Sr1−xLax)3Ir2O

et al. 2017

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“…Reduction of the raw data including Lorentz corrections, absorption, time-offlight spectrum, and detector efficiency corrections were carried out with anvred3. 27 The raw peaks were integrated using a 3-D ellipsoidal routine, 28 and the reduced dataset was refined using shelxl.…”

Section: Experimental and Computational Detailsmentioning

confidence: 99%

Structural investigation of the bilayer iridateSr3Ir2O7

et al. 2016

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A complete structural solution of the bilayer iridate compound Sr3Ir2O7 presently remains outstanding. Previously reported structures for this compound vary and all fail to explain weak structural violations observed in neutron scattering measurements as well as the presence of a net ferromagnetic moment in the basal plane. In this paper, we present single crystal neutron diffraction and rotational anisotropy second harmonic generation measurements unveiling a lower, monoclinic symmetry inherent to Sr3Ir2O7. Combined with density functional theory, our measurements identify the correct structural space group as No. 15 (C2/c) and provide clarity regarding the local symmetry of Ir 4+ cations within this spin-orbit Mott material.

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“…The intensity measurements were carried out at the IPNS on the SCD, a four-circle single-crystal diffractometer equipped with a position-sensitive area detector and employing the time-of-flight technique (Schultz, Srinivasan, Teller, Williams & Lukehart, 1984). The instrument was used in one fixed configuration, e)= 45, X = 0 and ~ = 90 °, y being the angle between the incident beam and the centre of the 30 x 30 cm detector.…”

Section: Methodsmentioning

confidence: 99%

Determination of the neutron absorption cross section for hydrogen as a function of wavelength with a pulsed neutron source

Howard¹,

Johnson²,

Schultz³

et al. 1987

J Appl Cryst

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The wavelength dependence of the neutron absorption cross section of hydrogen in [ReH3(C2H4) 2-{P(i-Pr)2Ph}2] was investigated by recording the decrease in Bragg peak intensity from a standard NaC1 crystal caused by attenuation of the incident beam by the Re sample. Data were collected on the Single Crystal Diffractometer (SCD) at the Intense Pulsed Neutron Source (IPNS, Argonne National Laboratory) which enabled concurrent measurements at a selection of wavelengths using the time-of-flight technique.To calculate the optimal absorption correction in a single-crystal neutron diffraction experiment, the linear absorption coefficient p of a sample should be determined directly by transmission measurements. In practice, however, it is common to calculate # from tabulated values of atomic absorption cross sections and knowledge of the size and contents of the unit cell.In this context hydrogen poses a problem, since its contribution to the attenuation of intensity is appreciable and not well characterized, although its cross section for true absorption is relatively small. This attenuation effect depends on the chemical environment of the bound hydrogen atom. It is hoped that the new results will be an improvement on the estimates currently used, and thereby be useful for future accurate structure determinations in areas such as electron density deformation experiments, where accurate corrections are of paramount importance (Coppens & Hall, 1983).The linear absorption coefficient is usually calculated from the expressionwhere #(2) is the linear absorption coefficient, V is the volume of the unit cell, n~ is the number of the ith type of atom in the unit cell and a,(2) is the effective absorption cross section (the sum of the true absorption and the incoherent scattering cross sections). The *And Chemistry and Materials Science and Technology Divisions, Argonne National Laboratory, Argonne, Illinois 60439, USA. summation runs over all elements present in the sample. The effective absorption cross section of hydrogen can be removed from this summation to givei~H where nn is the number of hydrogen atoms in the unit cell and a n is the effective absorption cross section of hydrogen. The summation now runs over all non-H elements, whose absorption cross sections are tabulated for a fixed wavelength and taken to be proportional to wavelength (Bacon, 1975) if the incoherent scattering cross sections are small, as is the case here.Hence (2) can be rewritten asi~H where ai (20) is the tabulated absorption cross section for the ith element at a wavelength 2o. Equation (3) is of the form where a = V/n n,i¢H These a and b are constants for a given compound and can be evaluated from crystallographic information and tabulated absorption cross sections.In this experiment p(2) is calculated from the measured attenuation through a known thickness of material using the Beer-Lambert law:where I is the path length in the sample. This principle has been used previously (Koetzle & McMullan, 1980) for crystals of organic molecules ...

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Single-crystal, time-of-flight, neutron-diffraction structure of hydrogen cis-diacetyltetracarbonylrhenate, [cis-(OC)4Re(CH3CO)2]H: a metallaacetylacetone molecule

Cited by 112 publications

References 1 publication

Doping-driven structural distortion in the bilayer iridate (Sr1−xLax)3Ir2O

Doping-driven structural distortion in the bilayer iridate (Sr1−xLax)3Ir2O

Structural investigation of the bilayer iridateSr3Ir2O7

Determination of the neutron absorption cross section for hydrogen as a function of wavelength with a pulsed neutron source

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