Sublimation properties of CoF3: mass spectrometric and quantum chemical studies

The sublimation of cobalt trifluoride was studied using the Knudsen effusio n method combined with mass spectrometry. The pressure of F was directly me asured for decomposition of CoF3(s) into CoF2(s). The average kinetic energ y of CoF2+, CoF+ and Co+ fragment ions was determined and the relative ioni sation cross section curves measured from 6 eV to 100 eV. Thermodynamic fun ctions of gaseous CoF3 and Co2F6, were evaluated from geometrical and vibra tional parameters provided from theoretical calculations. Heats of formatio n of CoF3(s), CoF3(g), Co2F6(g) were established as (-784 +/- 6) kJ/mol, (- 565 +/- 11) kJ/mol and (-1289 +/- 22) kJ/mol, respectively. Copyright (C) 2 001 John Wiley & Sons, Ltd.