Incommensurately modulated structure of ZnSiO(OH)·HO at high pressure.

High-resolution single-crystal X-ray diffraction experiments on ZnSiO(OH)·HO hemimorphite were conducted at high pressure using diamond anvil cells at several different synchrotron facilities (ESRF, Elettra, DESY). Experimental data confirmed the existence of a previously reported phase transition and revealed the exact nature of the incommensurate modulation. We report the incommensurately modulated structure described in the (3+1)D space group Pnn2(0, β, 0)000.

Charge density redistribution with pressure in a zeolite framework.

As a result of external compression applied to crystals, ions relax, in addition to shortening the bond lengths, by changing their shape and volume. Modern mineralogy is founded on spherical atoms, i.e.

Charge density studies of single and transient (single to double) boron-oxygen bonds in (NH)BO(OH)·2HO.

A HBO ion which makes up the (NH)BO(OH)·2HO crystal structure has two types of boron-oxygen bonds, single B-O bonds and an intermediate between single and double BO bonds. Differences between these two bond types are visible not only because they differ by their lengths but also a topology of electron density distribution differs. This also gives a hint as to how to distinguish between these two bond types.

Accurate crystal structure of ice VI from X-ray diffraction with Hirshfeld atom refinement.

Water is an essential chemical compound for living organisms, and twenty of its different crystal solid forms (ices) are known. Still, there are many fundamental problems with these structures such as establishing the correct positions and thermal motions of hydrogen atoms. The list of ice structures is not yet complete as DFT calculations have suggested the existence of additional and - to date - unknown phases.

Tracing electron density changes in langbeinite under pressure.

Pressure is well known to dramatically alter physical properties and chemical behaviour of materials, much of which is due to the changes in chemical bonding that accompany compression. Though it is relatively easy to comprehend this correlation in the discontinuous compression regime, where phase transformations take place, understanding of the more subtle continuous compression effects is a far greater challenge, requiring insight into the finest details of electron density redistribution. In this study, a detailed examination of quantitative electron density redistribution in the mineral langbeinite was conducted at high pressure.

Experimental charge density of grossular under pressure - a feasibility study.

X-ray diffraction studies of crystals under pressure and quantitative experimental charge density analysis are among the most demanding types of crystallographic research. A successful feasibility study of the electron density in the mineral grossular under 1 GPa pressure conducted at the CRISTAL beamline at the SOLEIL synchrotron is presented in this work. A single crystal was placed in a diamond anvil cell, but owing to its special design (wide opening angle), short synchrotron wavelength and the high symmetry of the crystal, data with high completeness and high resolution were collected.

Differences and similarities among hypoxanthinium nitrate hydrate structures.

Crystals of hypoxanthinium (6-oxo-1H,7H-purin-9-ium) nitrate hydrates were investigated by means of X-ray diffraction at different temperatures. The data for hypoxanthinium nitrate monohydrate (CHNO·NO·HO, Hx1) were collected at 20, 105 and 285 K. The room-temperature phase was reported previously [Schmalle et al.

Pressure-Dependent Structural and Luminescence Properties of 1-(Pyren-1-yl)but-2-yn-1-one.

The crystal structure of 1-(pyren-1-yl)but-2-yn-1-one ( 1 a , a polynuclear aromatic hydrocarbon displaying enhanced luminescence in the solid state, has been re-determined at several pressures ranging from atmospheric up to 3 GPa using a Diamond Anvil Cell (DAC). These experiments were augmented by periodic DFT calculations at pressures up to 4.4 GPa.

Ruthenium Complexes Bearing Thiophene-Based Unsymmetrical N-Heterocyclic Carbene Ligands as Selective Catalysts for Olefin Metathesis in Toluene and Environmentally Friendly 2-Methyltetrahydrofuran.

Three mono-N-heterocyclic carbene (NHC) ruthenium 2-isopropoxybenzylidene (10 a-c) and one bis(NHC) indenylidene complex (8) bearing an unsymmetrical N-heterocyclic carbene ligand were synthesized and structurally characterized by single-crystal X-ray diffraction. The catalytic activity of the newly obtained complexes were evaluated in ring-closing metathesis (RCM) and ene-yne (RCEYM) reactions in toluene and environmentally friendly 2-MeTHF under air. The results confirmed that although all tested reactions can be successfully mediated by catalysts 10 a-c, their general reactivity is lower than the benchmark all-purpose Ru catalysts with symmetrical NHC ligands.

An insight into real and average structure from diffuse X-ray scattering - a case study.

Two-dimensional diffuse X-ray scattering from an organic salt [N-(3-(2,6-dimethylanilino)-1-methylbut-2-enylidene)-2,6-dimethylanilinium chloride, C21H27N2(+)Cl(-)] was interpreted with the help of an analytical model of diffuse scattering. An analysis of the relationship between symmetry and diffuse scattering for the studied system has been undertaken. The symmetry of the system explains the extinction pattern, taking the form of curves, on the diffuse scattering planes.

Electrostatic matching versus close-packing molecular arrangement in compressed dimethyl sulfoxide (DMSO) polymorphs.

Single crystals of dimethyl sulfoxide (DMSO, (CH3)2SO) were in situ frozen at isochoric conditions in a diamond-anvil cell and their structures determined at 0.37, 0.56, and 2.

Pressure-freezing with conformational conversion of 3-aminopropan-1-ol molecules.

3-Aminopropan-1-ol, NH(2)(CH(2))(3)OH, was pressure-frozen and its structure determined at 0.2, 0.9 and 1.

Compressed hydrogen-bond effects in the pressure-frozen chloroacetic acid.

The competing effects of squeezed OH...

In-situ high-pressure study of the ordered phase of ethyl propionate.

Ethyl propionate, C5H10O2 (m.p. 199 K), has been in-situ pressure-frozen and its structure determined at 1.

Absence of halogen...halogen interactions in chlorotrimethylsilane polymorphs.

The structures of in situ pressure-frozen chlorotrimethylsilane crystals, (CH3)3SiCl, have been determined at 0.23, 0.30 and 0.