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 management in the Metropolitan Region of São Paulo rivers, creeks and other tributaries is declining by the year given that only half of the dwellings have some sort of solid waste collection system and most of the solid waste collected continues to be disposed of in the reservoir as many poor households still have no formal wastewater collection and disposal at all. Water management in the Metropolitan Region of São Paulo Water management in the Metropolitan Region of São Paulo, Brazil faces several challenges, including pollution of drinking water reservoirs that are surrounded by slums, water scarcity leading to conflicts with the Campinas Metropolitan area to the north,