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

Journal Article · Sun Jul 01 04:00:00 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), Journal Name: J. Chem. Phys.; (United States) Vol. 81:1; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

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