Carbodiimide – Class A reactions (2). (A) Rb48. (B) Rb50. Gibbs free-energy profiles computed at T_gas = 170 K and P_gas = 5.92 × 10⁻⁴ atm. The ΔG° values are calculated at CCSD(T)-F12/cc-pVTZ-F12, with their respective ZPVE corrected. Here, min = minimum (intermediate), ts = transition state, pw = pathway, prod = products; and charge and spin multiplicity are shown in parentheses. The energy units are given in kcal mol⁻¹. PES surfaces (lines and horizontal bars related to stationary points) are black when the energy of the next stationary point is submerged with respect to the energy of the reactants, and gray when this energy is lower. Atoms: gray = H, light blue = C, blue = N, red = O.