Ammonia or azane is a compound of nitrogen and hydrogen with the formula NH3. It is a colourless gas with a characteristic pungent smell. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or indirectly, is also a building-block for the synthesis of many pharmaceuticals and is used in many commercial cleaning products. Although in wide use, ammonia is both caustic and hazardous. The global production of ammonia for 2012 is anticipated to be 198 million tonnes, a 35% increase over the estimated 2006 global output of 146.5 million tonnes.

Ammonia, as used commercially, is often called anhydrous ammonia. This term emphasizes the absence of water in the material. Because NH3 boils at −33.34 °C (−28.012 °F) at a pressure of 1 atmosphere, the liquid must be stored under high pressure or at low temperature. "Household ammonia" or "ammonium hydroxide" is a solution of NH3 in water. The concentration of such solutions is measured in units of the Baumé scale (density), with 26 degrees baumé (about 30% w/w ammonia at 15.5 °C) being the typical high-concentration commercial product. Household ammonia ranges in concentration from 5 to 10 weight percent ammonia.

Read more about Ammonia:  Structure and Basic Chemical Properties, History, Synthesis and Production, Biosynthesis, Properties, Ammonia's Role in Biological Systems and Human Disease, Liquid Ammonia As A Solvent, Detection and Determination, Astronomical Observations and Research Applications, Safety Precautions