Rare earth hydrides formed by reaction of rare earth metals with water vapor

Journal Article · Tue Apr 01 04:00:00 EST 1980 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(80)90572-1· OSTI ID:6812504

Smith, H K; Moldovan, A G; Craig, R S; Wallace, W E; Sankar, S G

The reaction of Pr, Gd, Dy, and Er with water vapor has been studied in the temperature interval 100 to 140/sup 0/C. There was corroboration of the earlier observations of J. Dexpert-Ghys. et al. (J. Less Common Metals, 41, 105, 1975) to the effect that (1) DyH/sub 2/ forms when Dy is treated with water vapor and (2) there is no evidence by x-ray diffraction of the formation of Dy(OH)/sub 3/ and Dy/sub 2/O/sub 3/. Since the free energy change involved in forming DyH/sub 2/ and O/sub 2/ from Dy and H/sub 2/O is about + 17 kcal, the reaction was carried out under radiation in an effort to ascertain whether the missing energy was being photochemically supplied. Results were negative. Mass spectrometric examinations of the reacting system using O/sup 18/-enriched water showed no oxygen in the gaseous products. Study of the solid using Auger spectroscopy gave clear indication of large amounts of oxygen in the sample after reaction with water. Presumably the incorporation of oxygen in the lattice permits the thermodymamic requirements to be satisfied. Oxygen is not present in Dy in a phase with sufficient long-range order to give a detectable x-ray diffraction pattern. Pr and Gd in the form of filings react with H/sub 2/O to give dihydride and hydroxide. Er is unreactive as judged from x-ray diffraction measurements. 2 figures, 1 table.

• Research Organization: Univ. of Pittsburgh, PA
• OSTI ID: 6812504
• Journal Information: J. Solid State Chem.; (United States), Journal Name: J. Solid State Chem.; (United States) Vol. 32:2; ISSN JSSCB
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AUGER ELECTRON SPECTROSCOPY
CHEMICAL REACTORS
COHERENT SCATTERING
DIFFRACTION
DYSPROSIUM
DYSPROSIUM COMPOUNDS
DYSPROSIUM HYDRIDES
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY
ERBIUM
EVEN-EVEN NUCLEI
FLUIDS
FREE ENERGY
GADOLINIUM
GADOLINIUM COMPOUNDS
GADOLINIUM HYDRIDES
GADOLINIUM HYDROXIDES
GASES
HIGH TEMPERATURE
HYDRIDES
HYDROGEN COMPOUNDS
HYDROXIDES
ISOTOPES
LIGHT NUCLEI
MASS SPECTROSCOPY
MEDIUM TEMPERATURE
METALS
NONMETALS
NUCLEI
OXYGEN
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PHYSICAL PROPERTIES
PRASEODYMIUM
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM HYDRIDES
PRASEODYMIUM HYDROXIDES
RARE EARTH COMPOUNDS
RARE EARTHS
SCATTERING
SPECTROSCOPY
STABLE ISOTOPES
SYNTHESIS
THERMODYNAMIC PROPERTIES
THERMODYNAMICS
VAPORS
WATER VAPOR
X-RAY DIFFRACTION