Reactions of Negative Ions in the Gas Phase. II. NH2−

In mixtures of ammonia with carbon disulfide and carbonyl sulfide the NH2− ion is formed with considerable abundance and reacts to form several other negative ions. The principal products of reaction with CS2 were HS−, CS2−, and SCN. The principal products of reaction with COS were HS−, NH2S−, and OCN−. The rates of the various reactions are similar to those of many positive-ion-molecule reactions. The heats of formation of SCN− and OCN− ions were determined from appearance potentials of these ions from CH3NCS and CH3NCO to be − 4 and − 19 kcal/mole, respectively.