Heats of Formation of H3O+, H3S+, and NH4+ by Electron Impact

Abstract
Electron impact fragmentations of some simple organic molecules have been investigated, making use of excess energy measurements. The results give values for the heats of formation to be 143, 191, and 148 kcal/mole for H3O+, H3S+, and NH4+, respectively. These values are consistent with limitations imposed by ion–molecule reactions and with crystal‐lattice calculations.