High temperature vaporization and thermodynamics of scandium monophosphide

Journal Article · Sat Mar 01 00:00:00 EST 1980 · High Temp. Sci.; (United States)

OSTI ID:6970854

Franzen, H F; Hariharan, A V; Merrick, J A

The high temperature vaporization of ScP was investigated by mass spectrometric and target-collection Knudsen effusion techniques in the temperature range 1767-2209/sup 0/K. ScP/sub 1-x/(0 less than or equal to x less than or equal to 0.04) vaporizes congruently to the gaseous species Sc, P, and P/sub 2/. The equilibrium partial pressure of Sc is given by: log P/sub Sc/(atm) = -(28,159 +- 321)/T + (8.10 +- 0.15). The second-law enthalpy and entropy for the atomization reaction, corrected to 298/sup 0/K, are: ..delta..H/sup 0/ = 258.0 +- 2.3 kcal mol/sup -1/, ..delta..S/sup 0/ = 73.4 +- 1.4 eu; and ..delta..H /sub f/,298//sup 0/(ScP(s)) = -87.9 +- 2.5 kcal mol/sup -1/, S/sup 0/(ScP(s)) = 7.3 +- 1.4 eu. A temperature independent third law enthalpy of atomization (..delta..H = 252.2 +- 2.8 kcal mol/sup -1/) and enthalpy of formation (..delta..H/sub f//sup 0/(ScP(s)) = -82.1 +- 3.0 kcal mol) were obtained.

• Research Organization: Iowa State Univ., Ames
• OSTI ID: 6970854
• Journal Information: High Temp. Sci.; (United States), Vol. 12:1
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
PHOSPHIDES
ENTHALPY
ENTROPY
SCANDIUM COMPOUNDS
CRYSTAL STRUCTURE
EVAPORATION
PHASE TRANSFORMATIONS
PHOSPHORUS COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
360603* - Materials- Properties