Web site 'Thermodynamics of natural processes': radionuclides and toxic elements

Full text of publication follows: At present reliability and validity of the best thermodynamic data selection for chemical systems do not correspond to up-to-date experimental and theoretical studies of chemical thermodynamics. This is mainly due both to a wealth of those data and to labor consuming consistency procedure (global and local as well). The use of the modern-day information technologies developed in Internet could considerably improve this matter, particularly in the case when a special purpose site could be made. In this connection, a start has been made on the development of the web site 'Thermodynamics of natural processes' (www.tnpdata.ru) in 2004 by the 'DiaNIK' scientific group of Ecological-analytical Center of 'Dubna' University. The web site is designed for two users group: experts and users. The mentioned web site incorporates now results of our best values selection (Cp, S0, ΔfH0, ΔfG0, equilibria constants of the dissolution, hydrolysis, and complex formation reactions in aqueous solutions) for chemical systems containing radionuclides and toxic elements: MepOq-H2O and Me- C-N-P-H2O (Me = U, Th, Pu, Np, Se, As, Pb, Zn, Cd, Hg, Cu, Be). The selection is based on experimental thermodynamic data published up to the early 2004. To improve the recommended values one should reveal essential discrepancies between those incorporated in different reference books. The discrepancies clearly show the need for new experimental measurements [1]. Results obtained in this study permit us to revise some of the IAEA and NEA-TDB recommendations. Accepted as key values, new values of the NpO2+, NpO22+, PuO22+-ions thermodynamic properties provide excellent consistency of experimental thermochemical data and equilibria constants of dissolution reactions in the Np2O5-H2O, NpO3-H2O-CO2 and PuO3-H2O-CO2. This study was funded by Russian Foundation of Basic Research (projects N 04-05-64829, 01- 05-64352) and U.S. DOE (R60-20100-RW40USDOE-RAS; 2002-2003). [1] Medvedev, V. A., Khodakovsky, I.L., Bull. Chem. Thermod., 1977, 20, p. 564-566. (authors)