Sigrid Furuseth

Structural properties of Ni1−tRhtBi3

Abstract Complete solid miscibility is found for Ni 1− t Rh t Bi 3 (0.00 ⩽ t ⩽ 1.00). The crystal structure is of the NiBi 3 type and the positional parameters are found to vary insignificantly with composition t . The decomposition temperature decreases with increasing rhodium content from 753 ± 10 K for NiBi 3 to 445 ± 10 K for RhBi 3 .

Crystal structure and phase relations for Mn3Sn2 and non-stoichiometric Mn2−xSn

Abstract Ordered Mn3Sn2 appears as a distinct low-temperature phase in the binary MnSn system. On heating it decomposes peritectoidally around 813 K into the grossly non-stoichiometric Mn2−xSn phase and MnSn2. Phase relations are described for Mn3Sn2 and Mn2−xSn on the basis of samples where great care has been taken during synthesis to minimize inhomogeneity owing to manganese evaporation and/or transportation. Mn2−xSn exists between 753 and 1157 K. The non-stoichiometry of Mn2−xSn is strongly temperature dependent. At 1073 K, the homogeneity range is 0.18≤x≤0.23, whereas at 873 K 0.28≤x≤0.34. The crystal structure of Mn2−xSn is of the partly filled-up NiAs-type. The crystal structure of the ordered Mn3Sn2 phase was solved on the basis of powder X-ray and neutron diffraction data. Mn3Sn2 is isostructural to Co3Sn2 and Ni3Sn2. Phase transformation and structural relationships are discussed.

Polymorphism of chloroquine diphosphate

Abstract Chloroquine diphosphate was investigated by differential scanning calorimetry, thermogravimetric analysis, infrared spectroscopy, X-ray powder diffraction and by scanning electron microscopy for the indication of differences between anhydrous and hydrous polymorphs. The experiments clearly showed that the transition of anhydrous chloroquine diphosphate into hydrated compounds is possible by storing the drug at high relative humidity. Compression of the raw material did result in the formation of a new polymorph. This emphasizes the necessity for standardization of the manufacturing process of chloroquine diphosphate as well as a closer characterization of the solid drug as a part of the quality control.

Structural properties of the Ti1−xNbxS2 phase

Abstract The Ti 1−x Nb x S 2 phase crystallizing with the CdI 2 (1T) type of structure has been investigated. At 1000 °C and with a sulphur pressure of 6–8 atm the range of homogeneity is given by 0 x z parameter increases from the previously known value of 0.2501 in TiS 2 , through 0.2559 for x = 0.50 to 0.2611 for x = 0.95. The trigonal distortion of the metallic coordination polyhedron increases strongly and the interlayer distance of the structure decreases as titanium is substituted by the electron-richer niobium.

Low-temperature oxidative degradation of low-dimensional zirconium and hafnium tellurides

Abstract The penta-, tri- and ditellurides of zirconium and hafnium easily take up oxygen and become partly oxidized at and below room temperature. Complete oxidation of these phases to (amorphous) ZrO 2 or HfO 2 and (crystalline) Te is attained at some 320 to 500K (depending on compound, sample characteristics and experimental conditions) provided sufficient amounts of oxygen are available. Explanations for the different anomalies in ZrTe 5 are advanced as adsorbed/absorbed oxygen in the voids of the structure, partial oxidation, partial destruction of the Te III -Te III zig-zag chains in the structure and decomposition to the corresponding tritelluride and Te.