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The title compounds are prepared by melting and quenching of stoichiometric amounts of Rb2CO3, SiO2, and NiO or MnO (1573 K, 1.5 h for the Ni compound; 1673 K, 2 h for the Mn compound) followed by crystallization at 1193 K (12 h).

Sr2TiO(Si2O7), the Sr analogue of the mineral fresnoite Ba2TiO(Si2O7), is prepared by quenching a stoichiometric melt of SrCO3, TiO2, and SiO2 followed by annealing at 1323 K (7 d).

Analysis of a high-resolution synchrotron X-ray powder direction pattern of a dry-synthesized rubidium zinc silicate, leucite analogue Rb 2 ZnSi 5 O 12 , showed that this material has a cubic Ia3d structure. The structure of this material has been refined by the Rietveld method. Si and Zn atoms are disordered on tetrahedral framework sites and Rb occupies large channel sites along the [111] direction

Analyses of high-resolution synchrotron X-ray powder diffraction patterns of dry-synthesized MFe III Si 2 O 6 leucites (M=K, Rb, Cs) showed that the K- and Rb-containing leucites (iron potassium silicate, KFeSi 2 O 6 , and iron rubidium silicate, RbFeSi 2 O 6 ) each have a tetragonal I4 1 /a structure and the Cs-containing leucite (caesium iron silicate, CsFeSi 2 O 6 ) has a cubic Ia3d structure. The structures of these materials have been refined by the Rietveld method. In CsFeSi 2 O 6 leucite, Fe III and Si are disordered on tetrahedral framework sites as required by space-group constraints

It is shown by magnetometry and μSR spectroscopy that short-range magnetic interactions between the Mn cations in the nonmetallic K2NiF4-like phase La0.8Sr1.2Mn0.6Rh0.4O4 become significant below ∼200 K. Negative magnetoresistance (ρ/ρ(0) ∼ 0.5 in 14 T at 108 K) is apparent below this temperature. Neutron diffraction has shown that an applied magnetic field of 5 T is sufficient to induce saturated (3.38(7)μB per Mn) long-range ferromagnetic ordering of the atomic moments at 2 K, and that the induced ordering persists up to a temperature of 50 K in 5 T. Spin glass behavior is observed below 20 K in the absence of an applied field. The induced magnetic ordering is attributed to the subtle changes in band structure brought about by the external field, and to the controlling influence of Rh3+ over the relative strength of competing magnetic exchange interactions.

We have been using atomistic simulation for the last 10 years to study properties of imidazolium-based ionic liquids. Studies of dissolved molecules show the importance of electrostatic interactions in both aromatic and hydrogen-bonding solutes. However, the local structure strongly depends upon ion–ion and solute–solvent interactions. We find interesting local alignments of cations at the gas–liquid and solid–liquid interfaces, which give a potential drop through the surface. If the solid interface is charged, this charge is strongly screened over distances of a few nanometres and this screening decays on a fast time scale. We have studied the sensitivity of the liquid structure to force-field parameters and show that results from ab initio simulations can be used in the development of force fields.

We summarize results obtained by a combination of ab initio and classical computer simulations of dialkylimidazolium ionic liquids in different states of aggregation, from crystals to liquids and clusters. Unusual features arising from the competition between electrostatic, dispersion, and hydrogen-bonding interactions are identified at the origin of observed structural patterns. We also discuss the way Bronsted acids interact with ionic liquids leading to the formation of hydrogen-bonded anions.

[YC12(H20)6]C1, Mr = 303.356, monoclinic, P2/n, a = 7.8346 (25), b = 6.4729 (26), c = 9.5817 (50) angstroms, beta = 93.768 (35) °, V = 484.86 cubic angstroms, Z = 2, Dx = 2.0776 g cm -3, Mo Kalpha (A = 0.71069 angstroms),/z = 68.66 cm- 1, F(000) = 300, room temperature, final R = 0.0449 for 940 unique observed reflexions. The yttrium is coordinated, as expected, by two chlorines and six water molecules in a square antiprismatic arrangement.

The adducts formed between various aryl-substituted nitrones and aryl isocyanates have been shown, using 15N n.m.r. spectroscopy and X-ray crystallography, to be substituted 1,2,4-oxadiazolidinones and not the previously reported 1,3,4-oxadiazolinones.