Mass spectroscopic investigation of the equilibrium dissociation of gaseous Sb2, Sb3, Sb4, SbP, SbP3, and P2

摘要

Knudsen effusion mass spectroscopic studies of the vapor above a gadolinium antimonidehyphen;molybdenum phosphidehyphen;graphite system led to the determination of the standard enthalpy changes,Dgr; H298deg;lpar;kcalrpar;, for the following reactions:Sb4lpar;grpar;equals;2Sb2lpar;grpar; lpar;71.3 plusmn; 1.8rpar;,Sb4lpar;grpar; equals;4Sblpar;grpar;lpar;215.0 plusmn; 3.0rpar;,Sb2lpar;grpar; equals; 2Sblpar;grpar; lpar;71.8 plusmn; 1.0rpar;,Sb3lpar;grpar;equals;3Sblpar;grpar;lpar;129 plusmn; 4rpar;,P2lpar;grpar; equals;2Plpar;grpar;lpar;117.1 plusmn; 1.1rpar;,Sb2lpar;grpar; plus;P2lpar;grpar; equals; 2SbPlpar;grpar;lpar;17.6 plusmn; 0.4rpar;,SbPlpar;grpar;equals;Sblpar;grpar;plus;Plpar;grpar;lpar;86.0 plusmn; 1.2rpar;, and2SbP3lpar;grpar;equals;Sb2lpar;grpar;plus;3P2lpar;grpar; lpar;149 plusmn; 8rpar;. These reaction enthalpies have been combined with appropriate literature data to obtain the dissociation or atomization energiesDdeg;298and standard heats of formationDgr; Hdeg;f,298of the molecules given.D298deg;kcal molminus;1or kJ molminus;1Dgr; Hf,298deg;kcal molminus;1or kJ molminus;1Sb271.8 plusmn; 1.0300.4 plusmn; 4.854.7 plusmn; 2.2288.7 plusmn; 9.2Sb3129.0 plusmn; 4.0539.7 plusmn; 16.760.7 plusmn; 5.8254.0 plusmn; 24.3Sb4215.0 plusmn; 3.0899.6 plusmn; 12.637.9 plusmn; 5.4158.6 plusmn; 22.6SbP85.7 plusmn; 0.9358.6 plusmn; 3.857.3 plusmn; 1.6239.8 plusmn; 6.7SbP3285.8 plusmn; 5.21195.8 plusmn; 21.816.8 plusmn; 6.070.3 plusmn; 25.1