These salts are components ofperovskite solar cells, which are being evaluated for commercialization.[1] The iodide is the most commonly used. Magneto-optical data storage concepts are also being testing based on various ammonium halides.[2]
These compounds are usually prepared by combining equimolar amounts ofmethylamine with the appropriatehalide acid. For instance methylammonium iodide is prepared by combining methylamine andhydrogen iodide at 0 °C for 120 minutes followed by evaporation at 60 °C, yielding crystals of methylammonium iodide.[3]
These compounds' crystallography has been the subject of much investigation. J.S. Hendricks published an early paper on them in 1928.[4] Methylammonium chloride was investigated again in 1946[5] and methylammonium bromide in 1961.[6]
^Hughes, Edward W.; Lipscomb, William N. (1946), "The Crystal Structure of Methylammonium Chloride",J. Am. Chem. Soc.,68 (10):1970–1975,doi:10.1021/ja01214a029
