The high-pressure chemistry of potassium–copper mixtures

The chemistry of various potassium-copper mixtures placed in a Mao-Bell diamond anvil cell have been investigated up to pressures near 50 GPa. Characterization of these mixtures via X-ray diffraction suggests that several novel K–Cu phases form at these high-pressure conditions. The formation of intermetallic compounds with transition metals is illustrative of an entirely new body of chemistry for the heavy alkali metals, and has profound ramifications on geophysical research suggesting the presence of potassium in Earthʹs core. Additionally, such alkali metal–transition metal compounds may possess interesting electronic and structural properties, and this research serves as a welcome addition to the study of the K–Cu phase diagram.