Thermodynamic stability of CdMoO4 was determined
by measuring the vapor pressures of Cd and MoO3 bearing
gaseous species. Th vaporization reaction could be described as CdMoO4(s)+MoO2(s)
(n=3, 4 and 5). The vapor pressures of
the cadmium (pCd)
and trimer (p(MoO3)3)
measured in the temperature range 987≤T/K≤1111
could be expressed, respectively, as ln (pCd/Pa)
= –32643.9/T+29.460.08 and
ln(p(MoO3)3/Pa) = –32289.6/T+29.280.08. The standard molar Gibbs free
energy of formation of CdMoO4(s),
derived from the vaporization results could be expressed by the equations:
(s)0= –1002.0+0.267T14.5 kJ mol–1
(987≤T/K≤1033) and fGCdMoO4 (s)0
= –1101.9+0.363T14.4 kJ mol–1
(1044≤T/K≤1111). The standard enthalpy
of formation of CdMoO4(s)
was found to be –1015.414.5 kJ mol–1
Authors:N. Morozova, P. Semyannikov, S. Trubin, P. Stabnikov, A. Bessonov, K. Zherikova, and I. Igumenov
Volatile compounds of iridium(I): (acetylacetonato)(1,5-cyclooctadiene)iridium(I) Ir(acac)(cod), (methylcyclopentadienyl)
(1,5-cyclooctadiene)iridium(I) Ir(Cp’)(cod), (pentamethylcyclopentadienyl)(dicarbonyl) iridium(I) Ir(Cp*)(CO)2 and (acetylacetonato)(dicarbonyl)iridium(I) Ir(acac)(CO)2 were synthesized and identified by means of element analysis, NMR-spectroscopy, mass spectrometry.
Thermal properties in solid phase for synthesized iridium(I) complexes were studied by means of thermogravimetric analysis
in inert atmosphere (He). By effusion Knudsen method with mass spectrometric registration of gas phase composition the temperature
dependencies of saturated vapor pressure were measured for iridium(I) compounds and the thermodynamic characteristics of vaporization
processes enthalpy ΔHT* and entropy ΔST0 were determined. The energy of intermolecular interaction in the crystals of complexes was calculated.
Authors:N. Morozova, K. Zherikova, P. Semyannikov, S. Trubin, and I. Igumenov
Complexes of ruthenium(III) with the following beta-diketones: 2,4-pentanedione (Ru(acac)3), 1,1,1-trifluoro-2,4-pentanedione (Ru(tfac)3), 2,2,6,6-tetramethyl-3,5-heptanedione (Ru(thd)3), 2,2,6,6–tetramethyl-4-fluoro-3,5-heptanedione (Ru(tfhd)3) and 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione (Ru(ptac)3) were synthesized and identified by means of mass spectrometry. By effusion Knudsen method with mass spectrometric registration
of gas phase composition the temperature dependencies of saturated vapor pressure were measured for ruthenium(III) compounds
and the thermodynamic characteristics of vaporization processes enthalpy ΔHT* and entropy
Authors:N. Lahav, D. Ovadyahu, A. Gutkin, E. Mastov, T. Menjeritzki, A. Adin, L. Rubinstein, D. Tropp, and S. Yariv
A device was constructed in which a clay suspension is hermetically heated at 220°C for a few minutes. This thermal treatment
is accompanied by a pressure increase in the cell. Once the valve is opened, there is a fast release of the pressure inside
the cell and a sudden evolution of the interparticle water. This shock leads to a quasi explosion of the clay particle. This
technique was named thermal vapour pressure shock explosion (TSE). The effect of TSE treatment on the properties of palygorskite
suspensions was investigated. Palygorskite suspensions in water are rather unstable and particles smaller than 3 μm in size
are not found before a TSE treatment. Stabilization of the suspension can be obtained by TSE treatments and/or by using a
dispersing agent such as pyrophosphate, or both. As a result of TSE treatments smaller particles are obtained, the dispersiveness
of the particles is improved and electrophoretic mobility is increased. Electron microscopy scans showed that the aggregates
of needles which form the palygorskite fibres, disintegrate to separated thin needles as a result of the TSE treatment.
The effect of the water vapor pressure on the thermal dehydration of manganese(II) formate dihydrate was studied by means
of isothermal gravimetry under various water vapor pressure, ranging from 4.6 to 24.4 torr.
The kinetics of dehydration was described by a two-dimensional phase-boundary model,R2. The rate of dehydration decreased with increasing atmospheric water vapor pressure, but the Smith-Topley phenomenon was
not observed for the present dehydration. The activation energy and the frequency factor for the dehydration were 110–170
kJ·mol−1 and 1010–1016 cm·s−1, respectively. These values increased with increasing water vapor pressure, and were much larger than those reported for
the dehydration in vacuum.
Authors:V. I. Belevantsev, K. V. Zherikova, N. B. Morozova, V. I. Malkova, and I. K. Igumenov
[ 1 – 3 ]. In this aspect, complex investigations of the thermal properties of these compounds are important. Data on the saturated vaporpressure for crystal hafnium(IV) acetylacetonate, trifluoroacetylacetonate, pivaloyltrifluoroacetonate, and
Authors:A. Niskanen, T. Hatanpää, M. Ritala, and M. Leskelä
Normal pressure thermogravimetry (TG) measurements were used to study the sublimation behavior of several volatile metal compounds,
used as metal precursors in thin film fabrication by chemical vapor phase methods, like atomic layer deposition (ALD) and
chemical vapor deposition (CVD). The results indicated that dynamic TG measurements may be used to find correct source temperatures
to be used in an ALD reactor: a good correlation between the source temperatures used in ALD and temperatures corresponding
to mass losses of 10 and 50% in TG was verified. It was also found that isothermal TG measurements offer a simple way for
the vapor pressure measurements which otherwise are not trivial for solids with only moderate volatility.
Authors:Shekhar Kumar, M. Muthukumar, P. Sinha, U. Kamachi Mudali, and R. Natarajan
Phenyl trifluoromethyl sulfone (FS-13) is a polar diluent, proposed in literature as an alternate to nitrobenzene, in UNEX/HCCD-PEG
processes for better physical properties. Its PVT properties and accurate expression for estimation of its vapour pressure
are not available in the literature. Recently PVT properties of FS-13 were estimated by authors and its vapour pressure was
experimentally measured at temperatures ranging from 263.15 to 363.15 K. In this paper, results of these studies are presented.
Authors:J. Rouland, A. Thorén, J. Fournival, and R. Céolin
A theoretical temperature-specific volume-molar fraction (T-v-x) phase diagram of the binary systemA-H2O presenting a hydrateH with congruent melting is studied. The phase diagram is divided into two subsystems by the one-component phase diagram of
the hydrateH. The eutectic invariant planes which occur in both subsystems are described. The relationships between the invariants are
Isochoric and isoplethal theoretical sections are given. The one-component phase diagram of the hydrateH is described. It is pointed out that the triple line solid-liquid-vapour which relates the congruent melting is not necessarily
perpendicular to the molar fraction axis. The means that the three phases, solid, liquid and vapour, have not necessarily
the same composition.
TheT-v-x representation gives an explanation to the deviation between the maximum of the melting curve and the stoichiometric composition
of the hydrate which is often observed in theT-x binary diagramA-H2O.