Densities and apparent molal volumes of some aqueous rare earth solutions at 25.deg.. II. Rare earth perchlorates

Apparent molar heat capacities and apparent molar volumes ofY2(SO4)3(aq),La2(SO4)3(aq),Pr2(SO4)3(aq),Nd2(SO4)3(aq),Eu2(SO4)3(aq),Dy2(SO4)3(aq),Ho2(SO4)3(aq), andLu2(SO4)3(aq)atT= 298.15 K andp= 0.1 MPa

“…(10,50) However, these properties then begin to show some gradual shifts in the location of the initial break from Nd 3+ (aq) to some higher atomic number R 3+ (aq) at higher molalities where water sharing between ions or increasing complex formation may partially alter the hydration trends. In contrast, for the R(NO 3 ) 3 (aq) solutions, this two-series effect has already started to disappear by m = 0.1 mol · kg −1 , (51) apparently as a result of formation of significant amounts of rare-earth nitrate complexes.…”

“…Fairly extensive density information is available for most of the RCl 3 (aq), R(ClO 4 ) 3 (aq), and R(NO 3 ) 3 (aq) at T = 298.15 K. (9,10,12,17,(49)(50)(51)(52)(53)(54) Because these electrolytes are either essentially uncomplexed {R(ClO 4 ) 3 (aq)}, slightly complexed {RCl 3 (aq)}, or moderately complexed {R(NO 3 ) 3 (aq)} at the lower molalities, their V φ can be extrapolated to infinite dilution to obtain values of V • φ (R 3+ , aq, 298.15 K). Some of these densities were measured with pycnometers, (10,12,(49)(50)(51) others with a magnetically controlled float, (9,52) and the remainder with vibrating-tube densimeters.…”

“…Some of these densities were measured with pycnometers, (10,12,(49)(50)(51) others with a magnetically controlled float, (9,52) and the remainder with vibrating-tube densimeters. (17,53,54) The latter two types of measurements are capable of much greater precision than pycnometric measurements, and thus may yield much more reliable values of V • φ {R 3+ , aq, 298.15 K}.…”

The thermodynamics of aqueous trivalent rare earth elements. Apparent molar heat capacities and volumes of Nd(ClO4)3(aq), Eu(ClO4)3(aq), Er(ClO4)3(aq), and Yb(ClO4)3(aq) from the temperatures 283 K to 328 K

“…The non-Born term contributions to the HKF heat capacity model (C°p ,2 − vTX) are plotted in figure 8. (2) to (10) (2) to (10) Apparently, the discrepancies are not caused by differences in the solutions themselves because our solutions were prepared with a procedure identical to that used by Spedding et al (2) and the agreement between our values for V f,2 and Spedding's results (4) is excellent. Small systematic errors in the heat capacities measured by adiabatic solution calorimetry may account for the large discrepancies at low molalities.…”

“…Spedding and co-workers systematically studied various properties of the lanthanide salts in aqueous solution at T = 298.15 K. Among the properties studied were apparent molar volumes, (2,4) apparent molar heat capacities, (3,(22)(23)(24) enthalpies of dilution, (5) electrical conductivities, (7) and relative viscosities. (6) With the exception of the lanthanide nitrates, (22) the variation of each of these properties as a function of ionic radius across the lanthanide series exhibited a discontinuity consistent with the ''gadolinium break''.…”