Sulfides, reaction with acids

Barium hydroxide decomposes to barium oxide when heated to 800°C. Reaction with carbon dioxide gives barium carbonate. Its aqueous solution, being highly alkahne, undergoes neutrahzation reactions with acids. Thus, it forms barium sulfate and barium phosphate with sulfuric and phosphoric acids, respectively. Reaction with hydrogen sulfide produces barium sulfide. Precipitation of many insoluble, or less soluble barium salts, may result from double decomposition reaction when Ba(OH)2 aqueous solution is mixed with many solutions of other metal salts. 

In the reactions with carbonyl compounds9 and carboxylic acids,21 molybdenum(VI) fluoride is converted into molybdenum(VI) tetrafluoride oxide (MoOF4), and with the thiocarbonyl compounds24 into molybdenum(IV) sulfide, but with acid chlorides, its fate is not known. 

SAFETY PROFILE A poison by inhalation and ingestion. The powdered sulfide ignites spontaneously in air and some air-powder mixtures may be explosive. Trace carbon lowers the ignition temperature in air to 228°C and increases the sensitivity of air-dust mixtures. Heats up spontaneously and ignites with combustibles. Incompatible with water. When heated to decomposition or in reaction with acid or acid fumes it emits very toxic fumes of SOx. See also... 

BARIUM OXIDE (1304-28-5) BaO Noncombustible solid. The aqueous solution is a medium-strong base. Violent exothermic reaction with acids. Reacts exothermically with water or steam, forming heat and corrosive barium hydroxide may cause spontaneous combustion. Reacts violently with dinitrogen tetraoxide, hydrogen sulfide. 

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