Water of crystallization degree of hydration can be critical to the resulting chemical properties. For example, anhydrous RhCl is not soluble in water and is relatively useless in organometallic chemistry whereas RhCl•3HO is versatile. Similarly, hydrated AlCl is a poor Lewis acid and thus inactive as a catalyst for Friedel-Crafts reactions. Samples of AlCl must therefore be protected from atmospheric moisture to preclude the formation of hydrates. Crystals of hydrated copper(II) sulfate consist of [Cu(HO)] centers linked to SO ions. Copper is surrounded by six oxygen atoms, provided by two different sulfate groups and four molecules of water. A fifth water resides elsewhere
Water pollution in the United States which started to increase after the restriction to ocean dumping, helps reduce pollution particularly in areas where the surface water is not capable of assimilating elements such as nitrogen and phosphorus. The excessive amount of these chemical elements lead to pollution. With the widespread implementation of secondary treatment technology, water quality has greatly improved in many watersheds nationwide. However, many municipal plants are being challenged to confront some significant remaining problems: A growing body of water research during the late 1970s and 1980s indicated that stormwater runoff was a significant cause of water quality impairment in many parts of the