For diamagnetic 1-La, the signal in the Si MAS NMR spectrum at δiso = -102.6 ppm is assigned to the metalbound Si atoms (Figure ). The lineshape of this signal is consistent with an eight-line multiplet owing to the J coupling to 139 La (I = 7/2, 99.9% naturally abundant) where unequal lifetimes of the 139 La Zeeman states, which are on the order of the reciprocal of the J coupling (~290 Hz), cause variable broadening of the multiplet lines (see Supporting