Rietveld refinement of dry-synthesized Rb2ZnSi5O12 leucite by synchrotron X-ray powder diffraction. Erratum

Rietveld refinement of KLaTiO4 from X-ray powder data

Potassium lanthanum titanate(IV), KLaTiO(4), has been synthesized by conventional solid-state reaction. It crystallizes isotypically with the NaLnTiO(4) (Ln = La, Pr, Nd, Sm, Eu, Gd, Y and Lu) family. Five of the six atoms in the asymmetric unit (one K, one La, one Ti and two O atoms) are situated on sites with 4mm symmetry, whereas one O atom has 2mm. site symmetry. The crystal structure can b...

Clarithromycin form I determined by synchrotron X-ray powder diffraction.

The structure of the metastable form I polymorph of the macrolide antibiotic clarithromycin, C(38)H(69)NO(13), was determined by a powder diffraction method using synchrotron radiation. The space group of form I is P2(1)2(1)2. The initial model was determined by a molecular replacement method using the structure of clarithromycin form 0 as a search model, and the final structure was obtained th...

Automated parametric Rietveld refinement and its application to two- dimensional X-ray powder diffraction experiments

Identification of Polymorphic Forms of Active Pharmaceutical Ingredient in Low-Concentration Dry Powder Formulations by Synchrotron X-Ray Powder Diffraction

BACKGROUND The identification of different (pseudo) polymorphs of an active pharmaceutical ingredient in dry powder formulations is of importance during development and entire product lifecycle, e.g., quality control. Whereas determination of polymorphic differences of pure substances is rather easy, in dry powder formulations, it is generally difficult and the difficulties increase particularl...

Sr–fresnoite determined from synchrotron X-ray powder diffraction data

The fresnoite-type compound Sr2TiO(Si2O7), distrontium oxidotitanium disilicate, has been prepared by high-temperature solid-state synthesis. The results of a Rietveld refinement study, based on high-resolution synchrotron X-ray powder diffraction data, show that the title compound crystallizes in the space group P4bm and adopts the structure of other fresnoite-type mineral samples with general...