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γ-MnO2is a material formed by random intergrowth of two phases, β-MnO2andR-MnO2. It is demonstrated here on seven γ-MnO2samples that pair distribution function analysis using a conventional X-ray diffraction setup (Bragg–Brentano geometry with a molybdenum anode) allows the quantification of this intergrowth simplyviaa simulation of the actual material by a mixture of β-MnO2andR-MnO2phases. Although this method does not take into account specifically the relaxed distances in the vicinity of the intergrowth zone, it is found to be very robust, accurate and in full agreement with the widely used quantification based on the empirical approach of Chabre & Pannetier [Prog. Solid State Chem.(1995),23, 1–130].

The Rietveld method has proved to be a very effective means to characterize and quantify the crystalline phases and the amorphous phase in glass ceramic materials using X-ray powder diffraction data. The technique was applied to a borosilicate glass of the type used for high-level nuclear-waste containment, in order to measure the proportions of the crystallized phases after heat treatment and, thus, to qualify the thermal stability of the glass. Six crystalline phases were analysed in this way in an almost entirely (>95 wt%) amorphous material after adding a known proportion of an internal standard (TiO2). The quantitative analyses were corrected to allow for microabsorption effects resulting from grain-size and absorption-contrast effects. In addition to the quantitative data, unit-cell parameters and site-occupancy refinements revealed solid-solution and substitution phenomena in the crystal.

The INEL diffractometer, equipped with a CPS120 curved detector and set up in a Debye-Scherrer geometry, is a unique tool for carrying out powder diffraction studies on air-sensitive and/or small-volume samples. Although it has routinely been used in powder diffractometry because of its minute acquisition times, its accuracy in d-spacing and intensity measurements has not been clearly demonstrated before now. Concerning the d spacings, proper linearization of the CPS120 with a cubic Na2Ca3Al2F14 standard allowed a mean δ2θ difference of 0.006°. Intensity accuracy was measured with different highly and poorly absorbing samples. The accuracy is fairly good for the latter but poor for the former, except when special procedures such as the dilution of the sample with boron powder are used. A Rietveld calculation carried out on TI4V207 showed a very good agreement between the INEL Debye-Scherrer-geometry results and those obtained with a Philips diffractometer and Bragg-Brentano geometry.

A new triclinic polymorphic form of N,N'-diphenyl-1,4-phenylenediamine (C(6)H(5)NHC(6)H(4)NHC(6)H(5)) has been obtained through appropriate recrystallization of the orthorhombic form. It crystallized in the centrosymmetric space group P$\overline 1$, with two half molecules as the asymmetric unit.