Sesquioxides high temperature

This paper reviews data on certain thermodynamic aspects of the nonstoichiometric Pu-0 system, which may serve as a basis for use In reactor safety analysis. Emphasis Is placed on phase relationships, vaporization behavior, oxygen-potential measurements, and evaluation of pertinent thermodynamic quantities. Limited high temperature oxygen potential data obtained above the fluorite, diphasic, and sesquioxide phases In the Pu-0 system are presented. 

It should be emphasized that very little is quantitatively known about how the total pressures of plutonium-bearing species vary with oxygen potential, stoichiometry, and temperature in the bivariant region of oxygen-deficient plutonia between the phase limits at very high temperatures. New (though limited) oxygen potential data have been obtained in our laboratory above the fluorite, diphasic, and sesquioxide phases in the Pu-0 system at 1750, 2050, and 2250 K. 

Bismuth sesquioxide, BijOj, exhibits a high oxide ion conductivity at high temperature without doping of aliovalent cations. The oxide transforms from the monoclinic... 

Gallium sesquioxide is precipitated in hydrated form upon neutralization of acidic or basic solution of gallium salt. Also, it is prepared by thermal decomposition of gallium salts. Gallium oxide hydroxide, GaOOH [20665-52-5] on calcinations at high temperatures yields beta- Ga203. 

Analysis of the product obtained at high temperatures in air led both Berzelius and Wilm 4 to conclude that an oxide of composition represented by the formula RhO is produced but Claus 5 adduced evidence in favour of the,assumption that it is not a separate chemical entity, but a mixture of unoxidised metal and its sesquioxide. Leidie 6 in 1889 repeated the experiments of former investigators, obtaining somewhat similar results. He wisely pointed out that these cannot be regarded as conclusive evidence either way, and for the present the existence of rhodium monoxide must be regarded as uncertain. 

The sesquioxide (Rh203) adopts the corundum stracture at low temperatures and the perovskite structure at high temperatures. The latter form is usually obtained by heating the element or various compounds at 900-1000 °C. Prolonged heating of Rh(N03)3 at 730 °C yields the low-temperature form. 

As shown in Table I, lanthanum and lutetium oxides have Sq ground states and consequently their heat capacities should be attributed to lattice vibration. Data on these substances may be used to represent the lattice contribution to a first approximation for neighboring isostructural (and nearly so) sesquioxides. Cubic gadolinium oxide provides a midseries lattice heat capacity approximation at relatively high temperatures... 

Semiempirical calculations of free energies and enthalpies of hydration derived from an electrostatic model of ions with a noble gas structure have been applied to the ter-valent actinide ions. A primary hydration number for the actinides was determined by correlating the experimental enthalpy data for plutonium(iii) with the model. The thermodynamic data for actinide metals and their oxides from thorium to curium has been assessed. The thermodynamic data for the substoicheiometric dioxides at high temperatures has been used to consider the relative stabilities of valence states lower than four and subsequently examine the stability requirements for the sesquioxides and monoxides. Sequential thermodynamic trends in the gaseous metals, monoxides, and dioxides were examined and compared with those of the lanthanides. A study of the rates of actinide oxidation-reduction reactions showed that, contrary to previous reports, the Marcus equation ... 

The metal oxides thus far considered belong, in general, to the class of those which are reducible at moderately high temperatures in the presence of water or of alcohol. To the class of the so-called irreducible oxides of the metals and non-metals belong those of zinc, aluminum, molybdenum, silicon, and vanadium and chromium sesquioxide. The last has been described by Sabatier and Mailhe 06 as affording an excellent... 

Diyttrium trioxide EINECS 215-233-5 YO 3-245 Yttria Yttrium oxide Yttrium oxide (Y2O3) Yttrium sesquioxide Yttrium trioxide Yttrium(3 ) oxide. Phosphors for color TV tubes, yttrium-iron garnets for microwave filters, stabilizer for high-temperature service materials. Powder d = 5.03 LDso (rat ip) = 500 mg/kg. Atomergic Chemetals New Metals Chems. Ltd Noah Chem. Rhone-Poulenc Shin-Etsu Chem,... 

The high temperature heat capacity of the rare-earth sesquioxides is derived from measurements of the enthalpy increment H (T) H (298.15 K) using so-called... 

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