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 Republic of Ireland six-years from 2009 to 2015. In 2017 there was significant disruption to water supply services in parts of County Meath, County Louth and Drogheda, with 70,000 people without water for some time during July. The proportion of waste water discharges where secondary treatment facilities have been provided increased significantly from 26% between 1998–1999 to 93% by 2011. This was due predominantly to the new wastewater treatment plants at Ringsend (Dublin) (which, at the time, was believed to be the largest construction of a new water treatment facility in Europe serving 1.5million people), Cork City, Limerick City, Galway City and Dundalk.