Two internal rearrangement processes can be deduced from the temperature dependences of the 1H and 19F nuclear magnetic resonance (n.m.r.) spectra of the asymmetric puckered five-membered ring compounds (AsCH3)5, (AsCF3)5, and (PCF3)5. The first is a fast "butterfly" motion of the ring puckering which yields a time-averaged plane of symmetry perpendicular to the ring through the puckered atom. This motion could not be stopped in any of the three compounds by cooling, even to −130 °C in the case of (AsCF3)5. The second is a slow pseudo-rotation, or a rotation of the perpendicular symmetry plane around the ring yielding a time-averaged fivefold rotation axis. There is a choice between two mechanisms for this second rearrangement, either a "clickstop" process in which the puckering progresses around the ring by one position at a time, or a "pancake" process in which the puckering drops randomly into any one of the five ring positions from a planar transition state. This choice can be resolved for this cyclic permutation process by appeal to the n.m.r. lineshapes. The present data for (AsCH3)5 favor the "clickstop" mechanism in spite of a competing intermolecular process at elevated temperatures with other components in the system which are in equilibrium with the ring compound.