Complex Compounds

Certain compounds can appear in multiple forms yet mean the same thing. A common example is hydrates: water molecules bond to another compound or element. When this happens, a dot is shown between H₂O and the other part of the compound. Because the H₂O molecules are embedded within the compound, the compound is not necessarily "wet". When hydrates are heated, the water in the compound evaporates and the compound becomes anhydrous. These compounds can be used to attract water such as CoCl₂. When CoCl₂ is dry, CoCl₂ is a blue color wherease the hexahydrate (written below) is pink in color.

Ex. CoCl₂ ·6 H₂O