Dynamic properties of P4O6S and P4O7:31P spin-echo and 31P MAS-NMR investigations

The rotational dynamics of P4O6S and P4O7 in the solid state were studied by means of 31P NMR spectra of spinning and static powder samples in the temperature range of 153-295 K and 295-388 K, respectively. All spectra were simulated to confirm the type of the motion and to extract the time scales as a function of the temperature. Good agreement between experimental and theoretical data was obtained on the basis of a three-site jump model. For P4O6S, the activation energy and the pre-exponential factor derived from the lineshape simulations amount to 51(2) kJ/mol and 6(3) x 10(15) s(-1). For P4O7, the spectral analysis yields an activation energy of 67(1) kJ/mol and a pre-exponential factor of 6(2) x 10(14) s(-1). The dynamic behavior was checked independently by lineshape analyses under both MAS and static conditions. Activation energies are consistent within the errors for the lineshape analyses. Additionally, we have analyzed spin-lattice relaxation measurements, which show the correct trends for the activation energies.