It is an ammonium salt composed of methylamine and hydrogen chloride. ... Methylammonium iodide is the most commonly used, whereas using the chloride instead of, or as minor substituent to, the iodide provides the ability to tune the absorption, conductivity, and apparent bandgap.
Methylammonium halides are organic halides with a formula of CH3NH3X, where X is Cl for methylammonium chloride, Br for methylammonium bromide, or I for methylammonium iodide. Generally they are white or light colored powders.