Tris(bipyridine)ruthenium(II) chloride is the chloride salt coordination complex with the formula [Ru(bpy)]Cl.  This polypyridine complex is a red crystalline salt obtained as the hexahydrate, although all of the properties of interest are in the cation [Ru(bpy)], which has received much attention because of its distinctive optical properties.  The chlorides can be replaced with other anions, such as PF.