An investigation of arsenic and antimony additives in unseeded and potassium-seeded [formula omitted] flames

Abstract

Studies have been completed of the reactions involved with arsenic and antimony additives in H 2 O 2 flames and H 2 O 2 flames seeded with potassium. The flame was atmospheric and a molecular beam of the frozen species was introduced into the mass spectrometer through a four-stage differential pumping system operating from 1 to 10 −11 atm. Arsenic compounds found in the flame included AsO(g), HAsO 3(g) and H 3AsO 4(g). Heat of formation values, ΔH f298 , were calculated as −145.4±5 kcal/mole for HAsO 3(g) and −259.7±5 kcal/mole for H 3AsO 4(g). Antimony compounds included Sb(g), SbO(g), HSbO 3(g) and H 3SbO 4(g), yielding ΔH f298 values of 18.7±5 kcal/mole for SbO(g), −137.4±5 kcal/mole for HSbO 3(g), and −262.9±5 kcal/mole for H 3SbO 4(g). The formation of the potassium compounds KH 2AsO 4(g) and KH 2SbO 4(g) was also established. Heats of formation values, ΔH f298, obtained for the K-substituted compounds were −299.5±5 and −303.7±5 kcal/mole for KH 2AsO 4(g) and KH 2SbO 4(g), respectively.