Table 1. NICS(0) values (ppm) and relative energies (E_rel, kcal mol^–1) of model compounds X and Y in the pyramidal and planar structures.

Compound (structure)	NICS(0) (ppm)			E rel (kcal mol–1)
	a	b	c
X (pyramidal)	+0.20	–1.12	–9.45	0
X (planar)	–10.15	–11.99	–17.71	7.8
Y (pyramidal)	+5.52	+5.59	–2.91	9.4
Y (planar)	+3.67	+3.62	–4.35	28.5