Laboratory production of monophase pyrrhotite grains using solid–solid reaction and their characteristic infrared spectra

A new method of producing pyrrhotite grains, which are most commonly found in cometary material and interplanetary dust particles, was developed. Pyrrhotite grains in the monophase having a 7C structure were predominately produced using a solid–solid reaction between iron and sulfur grains at room temperature. The characteristic infrared peaks were observed at 602, 563, and 397 cm−1 (16.6, 17.8, and 25.2 μm).