Spectroscopies of magnesium sulfate double salts and their implication for Mars

Magnesium sulfate have been detected at multiple locations on Mars. The existence and distribution of magnesium sulfate and mixed cationic sulfate can be used as indicators of the sedimentary environment, and reveal the hydrological history and climate evolution of Mars. In this study, seven magnesium sulfate double salts were synthesized in the laboratory. These samples were performed by XRD to confirm their phase and homogeneity, and then the Raman, mid-infrared spectra, and visible near-infrared spectra of these samples were collected and analyzed. All of these spectra with different samples have their unique features that can be used to identify them on Mars and Earth. Generally speaking, these spectral data are helpful for the data processing of payloads with the same spectrum used in Mars exploration and can assist in the identification of Martian sulfates in the future (e.g., Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC), SuperCam, and ExoMars Raman Laser Spectrometer (RLS).