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

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

“…The effects of the overall hydration increase on thermodynamic and transport properties have been discussed in detail previously. (11,54,66,68,69,73) Values of C p,φ for these R X 3 (aq) electrolytes exhibit slightly more complicated behavior. At constant lower molalities, the values of C p,φ for the RCl 3 (aq) (15,16) and R(ClO 4 ) 3 (aq) (56) at T = 298.15 K are nearly constant from lanthanum to neodymium, increase with atomic number between neodymium and terbium, and then remain nearly constant for the remaining RCl 3 (aq) or increase slowly with increasing atomic number for the R(ClO 4 ) 3 (aq).…”

“…However, Xiao and Tremaine (54) have discussed the effect of changes in the hydration of the rare-earth ion on values of C • p,φ (R 3+ , aq, T ). Marcantonatos et al (74) analyzed the coupling between an inner-sphere hydration number equilibrium and an equilibrium for the formation of outer-sphere ion-pair complexes.…”

“…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}. a The experimental properties in these two columns, (ρ s − ρ w ) and 10 Available values of V φ for the RCl 3 (aq), R(ClO 4 ) 3 (aq), and R(NO 3 ) 3 (aq) were represented by the following extended Debye-Hückel equation:…”

“…Values of V φ determined with a magnetically controlled float (9,52) or a vibrating-tube densimeter (17,53,54) are generally significantly more precise and may be more accurate than results from pycnometric measurements. In some cases, pycnometric V φ values were also included in the least-squares calculations.…”

“…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.…”