Neodymium heat capacity

Lanthanide (III) Oxides. The lanthanide(III) oxides will be used to illustrate the present breadth of our most extensive knowledge of the chemical thermodynamics of lanthanide compounds. Cryogenic heat capacities of hexagonal (III) lanthanum, neodymium, and samarium oxides, together with those of cubic (III) oxides of gadolinium, dysprosium, holmium, erbium, and ytterbium, have been reported (90, 91, 195). In addition, those of thulium, lutetium, and a composition approaching that of cerium (III) oxide have also been determined, and five well-characterized compositions between PrOi.714 and PrOi.833 are currently under study (J93). 

NOG/PAU] Nogteva, V. V., Paukov, 1. E., Yarembash, E. I., The true heat capacity of rare-earth chalcogenides at low temperatures. II. The true heat capacity of neodymium selenide in the range 12.1-229°K and its standard entropy and enthalpy, Russ. J. Phys. Chem., 42, (1968), 121-122. Cited on page 373. 

A study of the crystal field interaction in NdAlg by heat capacity, susceptibility, and resistivity measurements over the range 4—300K has been reported. Thermal transformations in thiourea compounds of neodymium, samarium, europium, and gadolinium have been shown to take place according to the scheme M(C3H302)3, CS(NH2)2,3H20 M(C3M,02) CSfNH ) NH CNS MO-... 

Heat capacity values for the body-centered cubic and liquid phases for lanthanum to samarium show a poor correlation, but from these, a value of 44 J/(mol K) is selected for both phases for promethium. Based mainly on neodymium, a heat capacity value of 27.5 J/(mol K) is selected for the alpha phase at 298.15 K and 45.5 J/(mol K) at 1163 K based on a heat capacity difference of 1.5 J/(molK) at the transition temperature. An intermediate value of 35.0 J/(mol K) at 750 K is also selected based on the neodymium specific heat curve. These three values were used to represent the heat capacity of the alpha phase as... 

For the two common lanthanides lanthanum and neodymium that there are no quality heat capacity measurements available between 20 and 298 K and the selected entropy values at 298 K are therefore little more than educated guesses. Further measurements are also required on alpha cerium between 20 and 96 K in order to obtain a precision value for the entropy at 298 K. What is woiryingly being shown up by these reviews is that for many of these elements, selected values in a particular region are generally based on only one set of measurements since other measurements differ so significantly that they cannot be considered. It is possible that measurements on the pure metals will become fewer and fewer as there is a concentration oti commercially exploiting the many extraordinary properties of lanthanide compounds. 

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