Claim: Caesium bisulfate, obtained by combining Cs2SO4 and H2SO4, is considered as an inorganic compound that composes most of the Earth's crust.
Evidence: The caesium salt of bisulfate, it is a colorless solid obtained by combining Cs2SO4 and H2SO4. Caesium bisulfate or cesium hydrogen sulfate is an inorganic compound with the formula CsHSO4. Inorganic compounds comprise most of the Earth's crust, although the compositions of the deep mantle remain active areas of investigation.