High-pressure study of neptunium and plutonium compounds

Abstract

Neptunium and plutonium monopnictides and monochalcogenides were studied by x-ray diffraction at pressures up to 57 GPa. All of them exhibit structural phase transitions under pressure. The arsenides and tellurides have a CsCl (B2) type high-pressure structure. Sb as an anion favours a tetragonal high-pressure structure. The compressibilities were determined for all of the compounds studied. The results are compared to those obtained for the corresponding thorium and uranium compounds.     

General diagram of the phase remtions of actinide metals under pressure

Abstract

The proposed diagram is based on the results of high-pressure X-ray diffraction work and visualizes the general trends in phase relations of actinide metals under pressure. The transition from dhcp to ccp, which occurs under the action of pressure in heavy actinides and light lanthanides, also occurs with decreasing atomic number at ambient pressure. The same structural sequence is found in the lanthanide and the actinide metals, but its first two members, hcp and Sm-type, are missing in the actinide metals, and the phase transitions are shifted to lower pressures and higher atomic numbers in the actinides.     

Bulk moduli and high-pressure phases of the uranium rocksalt structure compounds: II. The monopnictides

Abstract

The high-pressure crystal structures of the compounds UX, where X = N, P, As and Sb, have been studied using X-ray diffraction in the pressure range up to about 60 GPa Rhornbohedral distortions are observed for UN and Up above 29 GPa and lO GPa, respectively. In Up a further transformation to an orthorhombic phase occurs at 28 GPa. UAs and USb transform to the CsCl structure at 20 GPa and 9 GPa, respectively. The latter transformations show a considerable hysteresis when the pressure is released. The scaling behaviour of the bulk modulus has been studied. It is confirmed that a log-log plot of bulk modulus versus specific volume for the cubic phases gives a straight line with a slope near ? 5/3.     

Temperaturmessung

Ohne Zusammenfassung     

Enhancing the Photo and Thermal Stability of Nicotine through Crystal Engineering with Gentisic Acid

The use of crystal engineering to convert liquids into crystalline solids remains a powerful method for inhibiting undesired degradation pathways. When nicotine, a liquid sensitive to both light and air, is combined with the GRAS-listed compound, gentisic acid, the resulting crystalline solid, exhibits enhanced photo and thermal stability. Despite a modest ΔT_m of 42.7 °C, the melting point of 155.9 °C for the nicotinium gentisate salt is the highest reported for nicotine-containing crystalline solids. An analysis of the crystal packing and thermodynamic properties provides context for the observed properties.     

Neuere Methoden zum Nachweis, zur Isolierung und quantitativen Bestimmung des Eiwei?es sowie seiner h?heren und tieferen Abbauprodukte

Ohne Zusammenfassung     

Schwefel- und Phosphorbestimmung

Ohne Zusammenfassung     

Die Destillation von Ammoniak bei der Stickstoffbestimmung

Ohne Zusammenfassung