Conglomerate‐to‐True‐Racemate Reversible Solid‐State Transition in Crystals of an Organic Disulfide‐Based Iodoplumbate

Switch over: All the disulfide moieties in the cations of an iodoplumbate display the same chiral conformation in a single crystal; however, during a phase transition (75 °C) half of these molecules undergo a conformational change, from the left- to the right-handed helical form, and a true racemate is formed. This transition is reversible, and thus this compound can act as a second harmonic generation switch.