Zirconium selenites

Nesterenko, Pinaev, and Pechkovskii [73NES/P1N] measured the vapour pressure of Se02(g) over zirconium(l V) selenite, Zr(Se03)2, in the temperature range 763 to 813 K by a membrane manometer. The equilibria were sluggish, but appear to be reversible, and 7 to 30 days were needed to reach a steady state. From the data furnished 

No data are available for a proper extrapolation of these data to standard conditions. On the assumption that for the reaction equals 2( C (Se02(g)) - 

Pashinkin and Gospodinov [94PAS/GOS] calculated the standard entropy of Zr(Se03)2 to be (196.5 33.5) J-K -mol from the same data. The auxiliary data used are not included in the paper. The mean value of the two entropy estimates is A° (Zr(Se03)2, cr, 298.15 K) = (210.0 25.0) J-K -mol. Being an estimate, this value is not selected. 

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The only zirconium selenite compound for which reliable chemical thermodynamic data are available is Zr(Se03)2(cr). Nesterenko et al. [73NES/PINJ investigated the dissociation of zirconium selenite via the reaction ... 

Using the solid zirconium selenite, labelled with Se by reactor irradiation, trace fluoride ion may be determinedusing the reaction ... 

The highly-insoluble selenite is mixed with PTFE powder in a small column. The solution containing F " is poured through the column and the released Se eluted with 0.25N-HC1. The activity of the eluate represents the amount of F " reacted. The method, which gives results with a precision of 5%, is applicable in the range 20—100 gg, the lower level being defined by the small, but finite, solubility of the zirconium selenite. 

Boisson, F., M. Gnassia-Barelli, and M. Romeo. 1995. Toxicity and accumulation of selenite and selenate in the unicellular marine algae Cricosphaera elongata. Arch. Environ. Contamin. Toxicol. 28 497-493. Bovee, E.C. and T.L. O Brien. 1982. Some effects of selenium, vanadium and zirconium on the swimming rate of Tetrahymena pyriformis a bioassay study. Univ. Kans. Sci. Bull. 52 (4) 39 44. 

Elements of Group VI up to 0.07 mole% Se02 into the gas phase. The low-temperature decomposition of the selenite ion is thought to involve the participation of the water of hydration since these water molecules are strongly distorted by the field of the cations and anions. The dissociation pressure of zirconium diselenite has been measured.316... 

Zirconium nisi forms n suUiie, ZrSo> 711,<. n wleimle, ZrfHi<>,)2 1 ll30, mill it selenite, Zr SeO,, 11,0. it Well le- various silll ile mid double Jilumlilllltes, If a 1 hi form salt. Willi i tie-, tait ine, citric, salicylic, and other tirnmiie acids... 

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