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 supply and sanitation in the Philippines and PEM, domestic wastewater discharges, agricultural wastewater, and industrial wastewater are the three main sources of water pollution. These are also known as "point sources" that emanate toxic substances into "non-point sources" or certain bodies of water. Domestic wastewater consists of sewage containing organic waste, solids, and coliforms produced by domestic activities such as laundry, bathing, cooking, and other kitchen activities. Agricultural wastewater, the major source of pollution in rural areas, contain pollutants resulting from agricultural and livestock activities like the maintenance of piggeries which usually do not have proper wastewater treatment facilities. Different industries also contribute largely to the