Hydration of lithium. beta. -alumina

Journal Article · Mon Nov 15 04:00:00 EST 1982 · J. Chem. Phys.; (United States)

OSTI ID:6809320

Dudney, N J; Bates, J B; Wang, J C

The hydration reaction of Li ..beta..-alumina has been studied using infrared measurements of large single crystals equilibrated at controlled water vapor pressure (2--80 kPa) and temperature (250--450 /sup 0/C) conditions. The equilibrium H/sub 2/O concentrations in the conduction plane can be carried continuously and reversibly up to a saturation limit of about 1.8 H/sub 2/O per unit cell. Values of the enthalpy and entropy for the hydration reaction at 300--450 /sup 0/C were determined to be ..delta..H = -102 kJ/mol and ..delta..S = -167 J/mol K. In Li ..beta..-alumina, some of the H/sub 2/O dissociates to form OH/sup -/ ions and H/sup +/ ions which are bound to lattice oxygen ions; the enthalpy for the dissociation reaction is approx.10 kJ/mol. In addition to OH/sup -/, H/sub 3/O/sup +/ and H/sub 5/O/sup +//sub 2/ species have been identified from the observed change in the equilibrium concentration with the water vapor pressure. The relative concentrations of the different types of OH/sup -/ species depend on the sample age. The hydration enthalpy for Na ..beta..-alumina of approx.-84 kJ/mol was determined from a similar study.

• Research Organization: Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
• OSTI ID: 6809320
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 77:10; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
640300 -- Atomic
Molecular & Chemical Physics
74 ATOMIC AND MOLECULAR PHYSICS
ALKALI METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
ENTHALPY
HYDRATION
INFRARED SPECTRA
LITHIUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REACTION HEAT
SOLVATION
SPECTRA
THERMODYNAMIC PROPERTIES