A new approach to the reverse Monte Carlo analysis of total scattering data from polycrystalline materials is presented. The essential new feature is the incorporation of an explicit analysis of the Bragg peaks using a profile refinement, taking account of the instrument resolution function. Other new features including fitting data from magnetic materials, modelling lattice site disorder and new restraint and constraint options. The new method is demonstrated by a brief review of studies carried out during its development. The new program RMCProfile represents a significant advance in the analysis of polycrystalline total scattering data, especially where the local structure is to be explored within the true constraints of the long-range average structure.

We report a study of the displacive phase transition in SrTiO 3 using neutron total scattering with analysis by the reverse Monte Carlo method. The resultant configurations have been analysed in terms of bond distance and bond angle distribution functions, and using recently developed methods based on geometric algebra (GA). The resultant picture is that the short-range order in SrTiO 3 closely follows the long-range order, with very little disorder in the high-temperature phase. This result is in contrast to similar work carried out on the displacive phase transition in quartz (Tucker et al 2000 J. Phys.: Condens. Matter. 12 L723-30). The differences between these two systems arises from the fact that there are many more Rigid Unit Modes in quartz, a point that is quantified by the GA analysis.

The high-temperature dehydroxylation and structural change of talc, Mg 3 (Si 2 O 5 ) 2 (OH) 2 , has been investigated in detail using infrared (IR) spectroscopy. The data (in the region of 20-12000 cm -1 ) on quenched samples show that absorptions from structurally incorporated OH and OD, as well as NH 4 -like species, have similar temperature dependences in dehydroxylation. The OH species exhibit weak variation in frequency on heating, which is inconsistent with thermally induced weakening of O-H bonds. Dehydroxylation in talc is a complex process that involves proton migrations and formation of new OH species. Additional fundamental OH bands near 3665 and 3745 cm -1 became detectable near 900 °C. On further heating the former disappear near 1200 °C, whereas the latter became undetectable near 1350 °C. The occurrence of CO 2 is observed in samples quenched between 600 and 1250 °C. The phonon spectrum (20-1500 cm -1 ) of the dehydroxylate (obtained by annealing the sample at 1000 °C) gives features signifi cantly different from that of talc, indicating the loss of the original layer structure. The IR data imply that the talc dehydroxylate consists of disordered SiO 2 and enstatite (MgSiO 3 ). Although MgSiO 3 exists dominantly in the form of orthoenstatite, the characteristic bands of clinoenstatite phase are found to coexist in the samples treated at 1000 °C. The IR data from in situ measurements show that protons become mobile at temperatures below the dehydroxylation and an extra OH species near 3500 cm -1 develops on heating. This new species is not quenchable, and it decreases intensity on cooling and disappears at room temperature. The in situ results also indicate external carbon-related substances can diffuse into talc during dehydroxylation.

A practical, one‐pot protocol is described for the conversion of carboxylic acids into amides through carboxyl activation by the reagent combination of trimethyl phosphite and iodine. This method integrates several advantages: (1) it allows amines to be chemoselectively acylated with excellent results in the presence of sulfur and oxygen nucleophiles; (2) the method shows wide generality in respect of solvent, base, and substrate; (3) the reagents used are widely available and much less expensive than common coupling reagents, and (4) the process is remarkably convenient, permitting extraction, recrystallization, and column chromatography as optional work‐up procedures. The chemoselectivity and generality of the method, the low cost, and wide availability of reagents combined with the ease of use make it a very favorable process.

We use neutron total scattering measurements with reverse Monte Carlo analysis methods incorporating an atom-swapping algorithm to identify the short-range Ca/Sr cation ordering within the Ca(x)Sr(1-x)TiO(3) solid solution (compositions x = 0.2,0.5,0.8). Our results show that nearest-neighbour pairs have a strong tendency for unlike Ca/Sr first-neighbour coordination in the x = 0.2 and 0.5 cases. In the x = 0.5 case the Ca/Sr ordering results in a structure with space group P 2(1)nm. In contrast, there is much less short-range cation ordering in the x = 0.8 case.