[mər′kyu̇r·ik ′bar·ē·əm ′ī·ə‚dīd] (inorganic chemistry) HgI2·BaI2·5H2O Crystals that are yellow or reddish and deliquescent; soluble in alcohol and water; used in aqueous solution as Rohrbach's solution for mineral separation on the basis of density. Also known as barium mercury iodide; mercury barium iodide.