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Ammonium chloride or Sal Ammoniac (chemically ammonium chloride (NH4Cl); also zalmiak, sal armagnac, sal armoniac, and salt armoniack) is, in its pure form, a clear white water-soluble crystalline salt with a biting taste.
In nature, the substance occurs in volcanic regions, forming on volcanic rocks near fume-releasing vents. The crystals deposit directly from the gaseous state, and tend to be short-lived, as they dissolve easily in water.
It is easy to produce artificially and is often created as a byproduct of other industries.
Uses
Historically it was considered one of the four alchemical "spirits". The way that it dissociates into two corrosive materials (ammonia and hydrochloric acid) which attack metals convinced eager alchemists that it might hold the key to converting one metal to another.
It is sold in blocks at hardware stores for use in cleaning the tip of a soldering iron and can also be included in solder as flux.
Other uses include a feed supplement for cattle, in hair shampoo, in textile printing, in the glue that bonds plywood, as an ingredient in nutritive media for yeast, in cleaning products, and as cough medicine. Its expectorant action is caused by irritative action on the bronchial mucosa. This causes the production of excess respiratory tract fluid which presumably is easier to cough up.
In several countries sal ammoniac is used to spice up liquorice-type dark candies (Finland's salmiakki is a popular example), and as a flavoring for vodkas.
In history
Sal Ammoniac was named after it was observed in the Temple of Zeus-Ammon in Egypt; its name means "salt of Ammon". It was the white crystalline substance that remained on the cieling and walls after camel dung was burnt. The modern name "ammonium" comes from sal ammoniac. There are a few stories of Alexander the Great finding such crystals in the coal seams of Tajikistan. The substance was known as naosha (Chinese: 硇砂; pinyin: náoshā) in China, nao sadar in India, and nushadir in Persia and Arabic-speaking countres.
See also
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