The pathway for the formation of carbonates includes four steps: 1) gaseous species are released from halogens and/or per(chlorate); 2) atmospheric ionization or dissociation occurs; 3) a gas phase reaction occurs between free species (CO2+, CO+) and different oxidants to produce different carbonate species; and 4) carbonates are deposited on the surface materials of Mars. The bottom image of a Martian dust storm comes from the Getty Images/Science Photo Library.