Ca[CO][CO] is a pyrocarbonate which can be formed at p, T-conditions prevalent in the Earth's transition zone.

Understanding the fate of subducted carbonates is a prerequisite for the elucidation of the Earth's deep carbon cycle. Here we show that the concomitant presence of Ca[CO] with CO in a subducting slab very likely results in the formation of an anhydrous mixed pyrocarbonate, , at moderate pressure ( ≈ 20 GPa) and temperature ( ≈ 1500 K) conditions. We show that at these conditions can be obtained by reacting Ca[CO] with CO in a laser-heated diamond anvil cell.

The adsorption of nitrobenzene over an alumina-supported palladium catalyst: an infrared spectroscopic study.

As part of an on-going programme of development of an aniline synthesis catalyst suitable for operation at elevated temperatures, the geometry of the adsorption complex for nitrobenzene on a 5 wt% Pd/AlO catalyst is investigated by infrared (IR) spectroscopy. an appreciation of the reduced site symmetry resulting from adsorption, application of the metal surface selection rule, and observation of in-plane modes only, the adsorption complex (Pd-nitrobenzene) at 28 °C is assigned as occurring vertically or tilted with respect to the metal surface, adopting () symmetry. Moreover, adsorption occurs a single Pd-O bond.

Phonon mechanism for the negative thermal expansion of zirconium tungstate, ZrWO.

Negative thermal expansion (NTE) in ZrWO was investigated using a flexibility analysis of phonons. It was shown that no previously proposed mechanism adequately describes the atomic-scale origin of NTE in this material. Instead it was found that the NTE in ZrWO is driven, not by a single mechanism, but by wide bands of phonons that resemble vibrations of near-rigid WO units and Zr-O bonds at low frequency, with deformation of O-W-O and O-Zr-O bond angles steadily increasing with increasing NTE-phonon frequency.

The contribution of phonons to the thermal expansion of some simple cubic hexaboride structures: SmB, CaB, SrB and BaB.

We have performed first-principles calculations of the structure and lattice dynamics in the metal hexaborides SmB, CaB, SrB and BaB using Density Functional Theory in an attempt to understand the negative thermal expansion in the first of these materials. The focus is on the role of Rigid Unit Modes involving rotations of the B octahedra similar to the rotations of structural polyhedra connected by bonds in Zn(CN), Prussian Blue and Si(NCN). However, it was found that there is very low flexibility of the network of connected B octahedra, and the lattice dynamics do not support negative thermal expansion except possibly at very low temperature.

Unique features of the structural phase transition in acetylene showing simultaneous characteristics of reconstructive, displacive and order-disorder.

We have studied the two phases of the molecular crystal acetylene, CH, using calculations of the lattice dynamics by Density Functional Theory methods. together with the use of classical molecular dynamics (MD) simulation methods. The two phases share the same simple face-centred cubic lattice arrangement of the molecular centres of mass, but with different molecular orientations.