Low-energy ball milling associated with a monomode microwave: a new route to synthesize manganese hexathiohypodiphosphate and to intercalate ionic species

Abstract

To synthesize manganese hexathiohypodiphosphate, stoichiometric mixtures of manganese, red phosphorus, and α-sulfur, together with potassium chloride, underwent low-energy ball milling under ambient conditions followed by exposure to the electromagnetic beam of a monomode microwave. X-ray diffraction patterns show that Mn 2P 2S 6 (structure MI, or H) has formed, as well as small amounts of intercalated KCl [these findings are supported by infrared (IR) observation]. Also some α-MnS have been formed. Electron diffraction patterns show the existence of structure H. They also reveal the emergence of the (up to now hypothetical) orthohexagonal structure and of some «turbostratic» layered material whose nature is not yet understood. Superconducting quantum interference device (SQUID) measurements show a ferromagnetic behavior, which can be assigned to the formation of some manganese monophosphide. Tetraethyl chloride ammonium is then easily intercalated as revealed by X-ray patterns and IR measurements. Finally, it has been shown that all three parameters (ball milling, microwave exposure, and presence of KCl as a catalyst) are necessary to form manganese hexathiophosphate. Filtrations and decantations lead to a pure hexathiophosphate compound.