Claim: Caesium bisulfate or cesium hydrogen sulfate, obtained by combining cesium sulfate and sulfuric acid, is considered as an inorganic compound that composes most of the Earth's crust.
Evidence: Caesium bisulfate or cesium hydrogen sulfate is an inorganic compound with the formula CsHSO4. Caesium sulfate or cesium sulfate is the inorganic compound and salt with the formula Cs2SO4. Sulfuric acid (American / IUPAC spelling) or sulphuric acid (traditional British spelling), also known as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with molecular formula H2SO4. The caesium salt of bisulfate, it is a colorless solid obtained by combining Cs2SO4 and H2SO4. Inorganic compounds comprise most of the Earth's crust, although the compositions of the deep mantle remain active areas of investigation.