Heat of formation of silicon tetrachloride

Abstract

The standard enthalpy of formation of silicon tetrachloride has been measured by reacting silicon with chlorine gas in the presence of an excess of liquid chlorine in a glass combustion vessel inside a calorimeter at 298 K. Under the conditions employed, complete reaction was achieved. Separate measurements were made to correct for the heat of evaporating part of the chlorine into the previously evacuated bulb and for that of mixing the remainder with liquid silicon tetrachloride. A value of ΔH°_f298(SiCl₄,l)=–165.49 ± 0.16 kcal/mol (–692.41 ± 0.67 kJ/mol) was found for the enthalpy of formation of liquid silicon tetrachloride.