These are all different compounds that contain the element Barium (Ba) but have different chemical formulas and properties.

BaO is barium oxide, which is a white solid commonly used in ceramics and as a precursor to other barium compounds.BaCl2 is barium chloride, a white crystalline solid that is soluble in water and commonly used in the production of other barium compounds.Ba(OH)2 is barium hydroxide, a white solid that is highly soluble in water and commonly used in the production of other barium compounds.