Calcium hydrosulfide is the chemical compound with the formula or . It is formed from the reaction of calcium hydroxide or calcium carbonate with hydrogen sulfide:
Ca(OH)<sub>2</sub> + 2 H<sub>2</sub>S â Ca(HS)<sub>2</sub> + 2 H<sub>2</sub>O
CaCO<sub>3</sub> + 2 H<sub>2</sub>S â Ca(HS)<sub>2</sub> + H<sub>2</sub>O + CO<sub>2</sub>
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