W.W. Wendlandt

The detection of quadruple points in metal salt hydrate systems by electrical conductivity measurements

Abstract The application of electrical conductivity measurements to the detection of liquid water and/or the quadruple point in metal salt hydrate systems is discussed. The apparatus used for the electrical conductivity measurements is described. The application of the technique is discussed for the CuSO 4 ·5H 2 O, BaCl 2 ·2H 2 O, and BaBr 2 ·2H 2 O systems.

A new look at the thermal properties of copper sulfate 5-hydrate

Abstract The dehydration of CuSO 4 · 5H 2 O was studied by sealed and open-tube DTA, QDTA, and by microreflectance and transmittance spectroscopy. By use of sealed-tube DTA, only two endothermic peaks were observed during the dehydration process; the first peak was due to the transition: while the second was probably the transition of the From QDTA, the heat of reaction of the first peak was found to be 12.9±0.6 kcal/mole; for the second peak a ΔH of 6.3±0.3 kcal/mole was found. The microreflectance and transmittance curves of single crystals of CuSO 4 · 5H 2 O also showed the formation of the 3-hydrate at elevated temperatures.

The deaquation and anation reactions of some anionoaquobis-(ethylenediamine)cobalt (III) complexes

The thermal deaquation and anation reactions of severai cisand trculs[Co(en)z(H10)z]X3-nH,0, (X = Cl-, Br-, and NO,-) complexes have previously been investigated by Chang and Wendlandt’. It was found that the chIoride complexes generally deaquated to give the c&[Co(en),C1,]CI complexes while the bromide complexes either gave the c&product or a mixture of cisand tramcomplexes. We wish to report here additional thermai deaquation studies of the cti-[Co(en),XY]Y Hz0 and cis-[Co(en),(H,O)X]Y. -H,O complexes, where X is Clor Brand Y is Bror N03-.

The high-temperature reflectance spectra of [Co(NH3)5H2O]X3 and [Cr(NH3)5H2O]X3 complexes

Abstract The HTRS and DRS of [Co(NH 3 ) 5 H 2 O]X 3 and [Cr(NH 3 ) 5 H 2 O]X 3 complexes were determined. The complexes undergo deaquation and anation reactions in the temperature range from 60 to 150°C. A reflectance minima shift to longer wavelengths was observed on heating the aquopentammine complexes.

High temperature reflectance spectroscopy: application to thermochromic compounds☆

Abstract The thermochromic behavior of Cu2[HgI4], Ag2[HgI4], Tl2[HgI4], Pb[HgI4], and Hg[HgI4] was investigated by the techniques of HTRS and DRS. The latter techniques are uniquely suitable for this type of atudy due to the dramatic color changes that the compounds exhibit during the thermochromic transitions.

The deltatherm dynamic adiabatic calorimeter: some applications

Abstract The Deltatherm dynamic adiabatic calorimeter is described. The operation and calibration of the instrument are discussed and its application to the determination of the C p of several metals and the Δ H of several dehydration reactions. The accuracy and precision of the calorimeter are about ± 1%.

Simultaneous gas evolution detection—dynamic reflectance spectroscopy: a new simultaneous thermal technique

Abstract A DRS—GED system in which the diffuse reflectance and the gas-evolution detection curves of the same sample are recorded simultaneously is described. The new system was used to study the dehydration of CuSO 4 ·5H 2 O and the deaquation and anation of [Co(NH 3 ) 5 H 2 O]Cl 3 .

The solid-state polymerization of cyanotetramminecobalt(III)-μ-cyanoaquotetrammine- cobalt(III) perchlorate: Effect of water vapor pressure

Abstract The effect of the water vapor pressure on the solid-state polymerization reaction of cyanotetramminecobalt(III)-μ-cyanoaquotetramminecobalt(III) perchlorate was investigated. The reaction temperature increased with increasing water vapor pressure. At a constant water vapor pressure, the reaction temperature increased as the heating rate increased. A reaction mechanism for these phenomena is postulated.

Thermal reactions of coordination compounds part III. Diaquotetrammine-, anionoaquotetrammine-, and dianionotetrammine-cobalt (III) complexes

Abstract The solid—solid and gas—solid reactions of [Co(NH 3 ) 4 X 2 ]Y 3−n ( n = 1, 2) complexes with NH 4 X and HX were studied by various thermoanalytical techniques. The trans -preferred products were formed in most cases provided that NH + 4 (H + ) and NO − 3 were both present in the reaction mixtures. With an excess of NO − 3 ion present, such as HNO 3 , the completely nitrated product was obtained, according to the equation: