Clare Bakewell
Angewandte Chemie International Edition,
August 1, 2022, Volume:
61, Issue:
31
Journal Article
Peer reviewed
“I'm always in a good mood when I get a really nice crystal structure. I think for an inorganic chemist, this never gets old … My first experiment was probably a complete disaster. And that's fine. ...Learning to cope with failure is an important part of research …” Find out more about Clare Bakewell in her Introducing … Profile.
The quality of diffraction data obtained using silver and molybdenum microsources has been compared for six model compounds with a wide range of absorption factors. The experiments were performed on ...two 30 W air‐cooled Incoatec IµS microfocus sources with multilayer optics mounted on a Bruker D8 goniometer with a SMART APEX II CCD detector. All data were analysed, processed and refined using standard Bruker software. The results show that Ag Kα radiation can be beneficial when heavy elements are involved. A numerical absorption correction based on the positions and indices of the crystal faces is shown to be of limited use for the highly focused microsource beams, presumably because the assumption that the crystal is completely bathed in a (top‐hat profile) beam of uniform intensity is no longer valid. Fortunately the empirical corrections implemented in SADABS, although originally intended as a correction for absorption, also correct rather well for the variations in the effective volume of the crystal irradiated. In three of the cases studied (two Ag and one Mo) the final SHELXL R1 against all data after application of empirical corrections implemented in SADABS was below 1%. Since such corrections are designed to optimize the agreement of the intensities of equivalent reflections with different paths through the crystal but the same Bragg 2θ angles, a further correction is required for the 2θ dependence of the absorption. For this, SADABS uses the transmission factor of a spherical crystal with a user‐defined value of μr (where μ is the linear absorption coefficient and r is the effective radius of the crystal); the best results are obtained when r is biased towards the smallest crystal dimension. The results presented here suggest that the IUCr publication requirement that a numerical absorption correction must be applied for strongly absorbing crystals is in need of revision.
The program Mercury, developed at the Cambridge Crystallographic Data Centre, was originally designed primarily as a crystal structure visualization tool. Over the years the fields and scientific ...communities of chemical crystallography and crystal engineering have developed to require more advanced structural analysis software. Mercury has evolved alongside these scientific communities and is now a powerful analysis, design and prediction platform which goes a lot further than simple structure visualization.
An overview of Mercury 4.0, an analysis, design and prediction platform that acts as a hub for the entire Cambridge Structural Database software suite, is presented.
A new microwave dielectric ceramic Zn2V2O7 with low sintering temperature was synthesized. The Zn2V2O7 exhibited a monoclinic structure with a densification temperature of 720 °C. The microwave ...dielectric properties, relative density, full width at half maximum (FWHM) of Raman spectra and packing fraction have been examined as a function of sintering temperature. Typically, the Zn2V2O7 ceramic possessed optimum microwave dielectric properties of εr = 9.67, Q × f = 23,968 GHz and τf = -19.87 ppm/°C.
Great interest has been attracted to enhancing the photoelectrochemical performances of BiVO.sub.4. However, there have rarely been reported about addressing their PEC stability. Herein, it is ...proposed that Fe ions doping could enhance the stability and PEC performances of BiVO.sub.4, which may because it could improve the crystalline structure and eliminates the crystal defects of BiVO.sub.4. Moreover, it is found that metal-organic framework can play a co-catalyst role during the PEC experiments. We designed and fabricated nanoporous Fe-doped BiVO.sub.4 modified with MIL-53(Fe), which exhibits much higher PEC performance and stability than pristine BiVO.sub.4 and Fe-doped BiVO.sub.4. It is believed that MIL-53(Fe) can capture the photogenerated holes and thus facilitates the charge separation efficiency. Graphical
The Inorganic Crystal Structure Database (ICSD) is the world's largest database of fully evaluated and published crystal structure data, mostly obtained from experimental results. However, the purely ...experimental approach is no longer the only route to discover new compounds and structures. In the past few decades, numerous computational methods for simulating and predicting structures of inorganic solids have emerged, creating large numbers of theoretical crystal data. In order to take account of these new developments the scope of the ICSD was extended in 2017 to include theoretical structures which are published in peer‐reviewed journals. Each theoretical structure has been carefully evaluated, and the resulting CIF has been extended and standardized. Furthermore, a first classification of theoretical data in the ICSD is presented, including additional categories used for comparison of experimental and theoretical information.
The article discusses how theoretical crystal data are supplementing experimental data for simulation and prediction of structures of inorganic solids in the Inorganic Crystal Structure Database.
The fabrication of multiple heterojunctions with tunable photocatalytic reactivity in full-range BiOBr–BiOI composites based on microstructure modulation and band structures is demonstrated. The ...multiple heterojunctions are constructed by precipitation at room temperature and characterized systematically. Photocatalytic experiments indicate that there are two types of heterostructures with distinct photocatalytic mechanisms, both of which can greatly enhance the visible-light photocatalytic performance for the decomposition of organic pollutants and generation of photocurrent. The large separation and inhibited recombination of electron–hole pairs rendered by the heterostructures are confirmed by electrochemical impedance spectra (EIS) and photoluminescence (PL). Reactive species trapping, nitroblue tetrazolium (NBT, detection agent of •O2 –) transformation, and terephthalic acid photoluminescence (TA-PL) experiments verify the charge-transfer mechanism derived from the two types of heterostructures, as well as different enhancements of the photocatalytic activity. This article provides insights into heterostructure photocatalysis and describes a novel way to design and fabricate high-performance semiconductor composites.
•Yb3+/Er3+ doped Mg-TCP upconversion materials have been synthesized via a two-step method.•Mg-TCP-8 %Yb3+/Er3+@800 °C samples show excellent upconversion luminescence.•Mg-TCP-8 %Yb3+/Er3+@800 °C ...samples are suitable for cellular endocytosis, demonstrating the potential application of bioimaging.
Yb3+ and Er3+ co-doped Mg-substituted tricalcium phosphate (Mg-TCP) upconversion particles were synthesized using a two-step process: Single-phase Mg-TCP-Yb3+/Er3+ materials with an average particle size ∼ 130.2 nm can be obtained by the hydrothermal reaction at 180 °C for 24 h, followed by heat treatment at 800 °C for 4 h, which demonstrated excellent upconversion green luminescence around the 520/550 nm wavelength. The culture of MC3T3-E1 cells with the extraction medium from Mg-TCP-8%Yb3+/Er3+@800°C materials showed obvious proliferation with increase of culture time and noncytotoxicity. Additionally, the intracellular imaging of Mg-TCP-8%Yb3+/Er3+@800°C through endocytosis by cells demonstrated that the particles can be significantly degraded within 24 h, which showed great potential for bioimaging applications.
Quan‐Ming Wang
Angewandte Chemie International Edition,
November 19, 2018, Volume:
57, Issue:
47
Journal Article
Peer reviewed
“The natural talent I would like to be gifted with is the ability to see crystal structures with the naked eye. When I was eighteen I wanted to be a mathematician …” Find out more about Quan‐Ming ...Wang in his Author Profile.
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