Intercalation in transition metal hexathiohypodiphosphates (MPS3), which proceeds by a unique ion-exchange route, is not well understood because it is difficult to follow the process in real time. Using a recently developed technique that allows the X-ray diffraction pattern of a suspension of an inorganic host lattice in a solution of guest molecules to be recorded in as little as 10 s, the intercalation of cationic species into MnPS3 has been investigated. The analysis of the kinetics at various temperatures is presented.