Henry's Law vaporization studies and thermodynamics of einsteinium-253 metal dissolved in ytterbium

Journal Article · Sun Jul 01 00:00:00 EDT 1984 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.447328· OSTI ID:6694786

Kleinschmidt, P D; Ward, J W; Matlack, G M; Haire, R G

The cohesive energy of metallic einsteinium determines whether einsteinium is a trivalent or divalent metal. The enthalpy of sublimation, a measure of the cohesive energy, is calculated from the partial pressures of einsteinium over an alloy. The partial pressure of /sup 253/Es has been measured over the range 470--870 K, using combined target and mass spectrometric Knudsen effusion techniques. An alloy was prepared with einsteinium dissolved in a ytterbium solvent to produce a very dilute solution. Partial pressure measurements on the alloy were amenable to the experimental technique and a data analysis using a Henry's law treatment of the data. Vapor pressure data are combined with an estimated crystal entropy S/sup 0//sub 298/ and ..delta..C/sup 0//sub p/ for ytterbium, to produce enthalpy, entropy, and free energy functions from 298 to 1300 K. The vapor pressure of einsteinium in a dilute einsteinium--ytterbium alloy is described by the equation log P(atm) = -(6815 +- 216)/T+2.576 +- 0.337, from which we calculate for the enthalpy of sublimation of pure einsteinium ..delta..H/sup 0//sub 298/ (second law) = 31.76 kcal/mol. The value of the enthalpy of sublimation is consistent with the conclusion that Es is a divalent metal.

• Research Organization: Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 6694786
• Journal Information: J. Chem. Phys.; (United States), Vol. 81:1
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
EINSTEINIUM 253
SUBLIMATION HEAT
THERMODYNAMIC PROPERTIES
ALLOYS
EVAPORATION
VAPOR PRESSURE
YTTERBIUM
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
EINSTEINIUM ISOTOPES
ELEMENTS
ENTHALPY
HEAVY NUCLEI
ISOTOPES
METALS
NUCLEI
ODD-EVEN NUCLEI
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
RADIOISOTOPES
RARE EARTHS
TRANSITION HEAT
360104* - Metals & Alloys- Physical Properties