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 crisis in the Democratic Republic of the Congo including Beni, Bunia, Lisala, Lubumbashi, Kisangani and Mbuji-Mayi. Water supply from deep-drilled wells is limited to a small percentage of the population. Most of the approximately 1,000 wells were constructed between the 1960s and 1990s and have yields between 15 and 80 m³/h. Hand and mechanical pump wells and dug wells account for around 10 percent of the drinking water supply. In 2015, there were still around 1 million people without access to "improved" water. In 2015, 76% of the population had access to an "improved" water source, 96% and 40% in urban and rural areas, respectively. Water withdrawals per