Release Of H2O Research Articles

Über die Thermische Zersetzung von Zink- und Cadmiumhexafluorosilikat

The simultaneous dehydration and decomposition of zinc and cadmium fiuorosilicates leads to the release of gaseous H2O and SiF4, which form amorphous SiO2. The difference of the weight loss measured by thermogravimetry from the calculated value can be accounted for on the basis of the reaction mechanism given. The reaction of H2O with SiF4 affects the thermal dehydration and decomposition of the fluorosilicates studied, and complicated energy effects also occur.

Scattering Properties of Ice Particles Formed by Release of H2O in Vacuum

Scattering Properties of Ice Particles Formed by Release of H2O in Vacuum

On the infra-red spectrum and thermal decomposition products of thaumasite, Ca3H2(CO3/SO4)SiO4.13H2O

SummaryThe infra-red spectrum of untreated thaumasite Ca3H2(CO3/SO4)SiO4.13H2O, as well as the spectra and X-ray diffraction patterns of thaumasite heated in air at 200, 360, 550, 725, 800, 900, and 1150° C were investigated. The release of CO2 and H2O upon heating was followed. It was established that thaumasite changes between 200 and 550° C to a glass-like, amorphous state. Ca2SiO4-polymorphs and anhydrite are formed upon heating at temperatures up to 800° C. From 900° C calcium silicosulphate and anhydrite are the thermal decomposition products. These results are used in the assignment of the IR-absorption bands under 1400 cm−1 of untreated thaumasite, which are shown to be of a composite nature, i.e. attributable to overlapping vibrations of both sulphate and silicate tetrahedra.

正方晶四塩化トリウムの高温における異常性について

Properties of ThCl4 were studied by means of X-ray powder diffraction, pressure measurement by the Burdon gauge and gravimetric analysis by a thermobalance. To prevent the hygroscopic chloride from hydration, all samples were treated in dry atmosphere.The X-ray pattern of ThCl4 powder prepared by chlorination showed a body-centered tetragonal type, in good agreement with the known structure as anhydrous chloride. But in the case of the vapor pressure measurement below 900°C, a markedly irreversible change in pressure was observed on heating and cooling, and retained gas of considerable pressure was found even at room temperature. On gravimetric analysis of tetrachloride in vacuum, a weight loss of 6∼10% was seen below 400°C, where sublimation of chloride was scarcely observed. After sublimation proceeded above 500°C, the weight loss finally ceased and an insoluble residue was formed. Moreover, the gas release of H2O and HCl, and the formation of ThOCl2 and ThO2 were confirmed in the course of heating the ThCl4 powder in vacuum. It is considered from the above results that body-centered tetragonal ThCl4 is not of the anhydrous but the hydrated phase containing a considerable amount of H2O in the crystalline state. Anomalous behaviors of ThCl4 can be attributed to dehydration and hydrolysis. In the course of stndies, the phase of ThOCl2 was identified and its X-ray diffraction data was established.