Two polymorphs of LaTaTiO6, i.e. monoclinic and orthorhombic, were synthesized by solid-state reaction technique. Both were found to be isostructural with analogous niobium compounds which were used as structural models. Structural characterization was performed on X-ray powder data by Rietveld refinement procedure which resulted in final Rwp values of 7.01 and 7.52% for orthorhombic and monocl...

Advance Access publication 21 May 2014 may be very difficult to go much <1%, even with the additional use of the Rietveld refinement in X-ray diffraction (LOQ = 0.76%). We are unaware of any method that has been published for the determination of crystalline silica in bulk materials that can measure down to 0.1%. If the laboratory used by Radnoff and Kutz has been able to modify NIOSH 7500 to a...

Oxygen vacancy (VO) strongly affects the properties of oxides. In this study, we used X-ray diffraction (XRD) to study changes in the VO concentration as a function of the Co-doping level of ZnO. Rietveld refinement yielded a different result from that determined via X-ray photoelectron spectroscopy (XPS), but additional maximum entropy method (MEM) analysis led it to compensate for the differe...

When solving the crystal structure of complex molecules from powder data, accurately locating the global minimum can be challenging, particularly where the number of internal degrees of freedom is large. The program Mogul provides a convenient means to access typical torsion angle ranges for fragments related to the molecule of interest. The impact that the application of modal torsion angle co...

A procedure of the structure factor simulation from a continuous electron density representation in combination with the full-profile structure refinement (Rietveld technique) was developed and applied to structural characterization of pure siliceous mesoporous mesophase materials C16SiO2-MMM of the MCM-41 type. An analytical function was exploited to simulate the continuous electron density. T...

Z. Naturforsch. 2009, 64b, 487 – 490; received February 20, 2009 The title compound has been synthesized under 4 GPa and at 500 ◦C from Na2O and MnO as starting materials. Rietveld refinement of the X-ray powder pattern indicates that Na6MnO4 is isostructural to Na6ZnO4 and thus is representing the second manifestation of an “isolated” [MnO4]6− anion after Na14Mn2O9. The compound crystallizes i...

The hydration behaviour of Ca3Al2O6, Ca12Al14O33 and CaAl2O4 with added amorphous silica at 40, 65 and 90 1C has been studied for periods ranging from 1 to 31 days. In hydrated samples crystalline phases like katoite (Ca3Al2(SiO4)3 x(OH)4x) and gibbsite, Al(OH)3, were identified, likewise amorphous phases like Al(OH)x, calcium silicate hydrates, C–S–H, and calcium aluminosilicate hydrates, C–S–...