A generalized analytic correlation is presented for activity coefficient. osmotic coefficient, enthalpy, and heat capacity of single and multicomponent strong aqueous solutions. A good correlation for each salt to an ionic strength of six is obtained by assigning a single parameter "B" value to each salt. These B values are well approximated by assigning two parameters for each ion. Values presented for the common ions at 25OC allow the estimation of activity and osmotic coefficients of many unmeasured salt solutions. CONCLUSIONS AND SIGNIFICANCEThe activity coefficients of strong aqueous electrolytes are well correlated by the single parameter Equation (4)to an ionic strength of about six. Equations derived from this for other thermodynamic properties are given by Equations (5) through (13).Individual '3'' values are found to be well represented by Equation (14) which involves two parameters per ion. This implies that for strong electrolytes only physical interactions are involved.Equations ( Inspection of Meissner's curves at high concentration indicates that, to a first approximation at high ionic strength, ( l / ( Z + Z -) ) log y r is linear with ionic strength and that a single parameter per salt provides a fair approximation to the activity coefficient variation over the entire range of ionic strength. Meissner also showed that the functional dependence is essentially temperature independent, although the parameter (equivalent to B) may be temperature dependent. March, 1973
Based on new experimental data presented for the boiling point elevation of natural sea water solutions, smoothed tabular values are presented for boiling point elevation (BPE), osmotic coefficient, water activity, osmotic pressure, and minimum separation energy to 2OOOC and 12oJ, sea salt.The concentration of sodium chloride solutions having the same water activities as sea salt solutions is also presented.Rigorous thermodynamics and the equations for strong electrolytes by Bromley (1973) were used for the correlation together with previously obtained heat capacity and enthalpy data and equations. A simplified equation is presented for boiling point elevation.
Since lattice energy calculations have indicated that the most stable sulfides of the periodic system could be expected in the neighborhood of the elements of the rare earth and actinide series, a thorough study of the sulfides of typical representatives of these elements was made. This paper describes the results of the study of the sulfides of thorium and uranium.The earliest careful study of thorium and uranium sulfides is that of Picon4r6sB who studied methods of preparation of ThS2 and US2 and the properties and reactions of these compounds. Strotzer and Zumbusch7 and Strotzer, Schneider and Biltz8 extended the study to polysulfides above the MS2 compounds and to oxidation states below the four plus state. However, due to very extensive oxygen contamination during preparation, the compositions and composition ranges given for the various phases below MS2 were greatly in error.In the present work both uranium and thorium were found to have compounds of the 2f oxidation state, US and ThS, which have the NaCl crystal structure. No compounds below the 2+ oxidation state were found. The solid solution ranges for these compounds appear to be relatively small. The next phase found above the MS phase was a M& phase corresponding to the 3f oxidation state. Both U2S3 and Th&s were found to have the same orthorhombic structure with apparently relatively small solid solution ranges. Th83 is an unusual thorium compound as i t is the only definitely established compound observed to date which contains thorium in the 3+ oxidation state. ThSz prepared by conversion of the oxide by H2S in a graphite container had the orthorhombic PbCt structure. US2 was prepared in a similar manner. Upon heating under reduced pressures, both lost sulfur through a solid solution range. US2 was less stable than ThSz and lost sulfur a t lower temperatures. A compound, Th&, of hexagonal structure, has been prepared by heating liquid ThS2 above 1950' under reduced pressures. It has a homogeneity range of approximately ThS1.71--1.,6. Because of the ready loss of sulfur, the study of the uranium sulfide range down (1) This work was performed under Manhattan District Contract to a composition corresponding to Th&2 did not give definite results. Experimental I. Preparation of the Sulfides of Uranium and Thorium.-Four different methods of preparation will be described below. The first three methods were also used for the preparation of the cerium sulfides and the apparatus used and details of the procedures may be obtained from the paper by Eastman, Brewer, Bromley, Gilles and Lofgreno on the cerium sulfides.Method 1.-This method is suited only for ThS2 and US2 since it involves the treatment of the oxides with excess H2S in a carbon system. Thus one obtains the highest sulfide stable at the temperature of the preparation. The temperature of the reaction should be varied between 1200-1300°; the rate of reaction a t these temperatures is fairly rapid. During the course of the reaction, the oxysulfides ThOS and UOS are first formed at lower temperature ...
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