Sodium amide, commonly called sodamide (systematic name sodium azanide), is the inorganic compound with the formula . It is a salt composed of the sodium cation and the azanide anion. This solid, which is dangerously reactive toward water, is white, but commercial samples are typically gray due to the presence of small quantities of metallic iron from the manufacturing process. Such impurities do not usually affect the utility of the reagent. conducts electricity in the fused state, its conductance being similar to that of NaOH in a similar state. has been widely employed as a strong base in organic synthesis. Preparation and structure Sodium amide can be prepared by the reaction of sodium with ammonia gas, but it is usually prepared by the reaction in liquid ammonia using iron(III) nitrate as a catalyst. The reaction is fastest at the boiling point of the ammonia, c. −33 °C. An electride, , is formed as a reaction intermediate. is a salt-like material and as such, crystallizes as an infinite polymer. The geometry about sodium is tetrahedral. In ammonia, forms conductive solutions, consistent with the presence of and ions. Uses Sodium amide is mainly used as a strong base in organic chemistry, often in liquid ammonia solution. It is the reagent of choice for the drying of ammonia (liquid or gaseous). One of the main advantages to the use of sodium amide is that it mainly functions as a nucleophile. In the industrial production of indigo, sodium amide is a component of the highly basic mixture that induces cyclisation of N-phenylglycine. The reaction produces ammonia, which is recycled typically. Dehydrohalogenation Sodium amide induces the loss of two equivalents of hydrogen bromide from a vicinal dibromoalkane to give a carbon–carbon triple bond, as in a preparation of phenylacetylene. Usually two equivalents of sodium amide yields the desired alkyne. Three equivalents are necessary in the preparation of a terminal alkynes because the terminal CH of the resulting alkyne protonates an equivalent amount of base. Hydrogen chloride and ethanol can also be eliminated in this way, as in the preparation of 1-ethoxy-1-butyne. Cyclization reactions Where there is no β-hydrogen to be eliminated, cyclic compounds may be formed, as in the preparation of methylenecyclopropane below. Cyclopropenes, aziridines and cyclobutanes may be formed in a similar manner. Deprotonation of carbon and nitrogen acids Carbon acids which can be deprotonated by sodium amide in liquid ammonia include terminal alkynes,