Studies of transition metals/metal compounds by high temperature mass spectroscopy and laser vaporization techniques

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1993

OSTI ID:7283772

Thiem, T L

The high temperature/laser vaporization experiment used to obtain thermochemical data for transition metals and metal compounds is described. High-temperature equilibrium reactions involving transition metals and oxygen were studied. Results include the determination of the enthalpy, [Delta]H, for the gaseous equilibrium OsO[sub 4] (g) [r equilibrium] OsO[sub 3] (g) + 1/2 O[sub 2] (g) over 1139-1471 K, resulting in a second-law heat of reaction [Delta]H[sub 305] (II) = 38.5 [+-] 3.3 kcal mol [sup [minus]1], which yields the standard enthalphy [Delta]H[sub 298] (II) = 39.2 [+-] 3.3 kcal mol[sup [minus]1] and a third-law heat of reaction [Delta]H[sub 298] (III) = 45.2 [+-] 1.7 kcal mol[sup [minus]1]. An average standard enthalpy of [Delta]H[sub 298](II) and [Delta]H[sub 298](III), 42 [+-] 7 kcal mol[sup [minus]1] is reported for the equilibrium. The heat of formation for gaseous OsO[sub 3] is [Delta][sub f]H[degrees][sub 298](OsO[sub 3]) = 39 [+-] 7 kcal mol[sup [minus]1], leading to a bond energy for O-OSO[sub 3] of 101 [+-] 7 kcal mol[sup [minus]1]. The ionization potentials for OsO[sub 3] and OsO[sub 4] were found to be 11.4 [+-] 0.2 and 12.3 [+-] 0.2 eV. Equilibrium reactions involving Ni(g) + 1/2O[sub 2](g)[r equilibrium] NiO(g) and Zn(g) + 1/2O[sub 2](g) [r equilibrium] ZnO(g) were studied. The [Delta][sub f]H[degrees][sub 298](II,III)[NiO(g)] and D[degrees][sub 0] (II,III)[NiO (g)] determined reinforce literature values. A lower limit for the standard heat of formation for ZnO(g) is determined based on the detection limit. The laser vaporization experiment replaced the Knudsen cell with a disc of a material is irradiated by a pulsed laser beam, Neutral and ionic atom beams of kinetic energy 3-300 eV are generated. The neutral atom's energy can be controlled with the laser power. Initial results of studies done on copper, nickel, zinc and related oxide, sulfide, bromide, and chloride salts are discussed.

• Research Organization: Massachusetts Univ., Lowell, MA (United States)
• OSTI ID: 7283772
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606 -- Other Materials-- Physical Properties-- (1992-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CHEMICAL REACTION KINETICS
ELECTROMAGNETIC RADIATION
EVAPORATION
KINETICS
LASER RADIATION
MASS SPECTRA
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
RADIATIONS
REACTION KINETICS
SPECTRA
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS