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Hydrogen cyanide
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<p>Hydrogen cyanide (formerly known as prussic acid) is a <a href="/facts/Chemical_compound/37FXqqtv">chemical compound</a> with the <a href="/facts/Chemical_formula/hghUtthl">formula</a> HCN and <a href="/facts/Structural_formula/XRTmvINB">structural formula</a> H−C≡N. It is a highly <a href="/facts/Toxic/qa96rs60">toxic</a> and <a href="/facts/Flammable/1QexTQ4T">flammable</a> liquid that <a href="/facts/Boiling/BHxWzT2k">boils</a> slightly above <a href="/facts/Room_temperature/YHwUIUTE">room temperature</a>, at 25.6 °C (78.1 °F). HCN is produced on an industrial scale and is a highly valued <a href="/facts/Precursor_(chemistry)/dUw8Mx2Y">precursor</a> to many chemical compounds ranging from <a href="/facts/Polymers/eF32E50K">polymers</a> to pharmaceuticals. Large-scale applications are for the production of <a href="/facts/Potassium_cyanide/xcoXn4I8">potassium cyanide</a> and <a href="/facts/Adiponitrile/h3RFognU">adiponitrile</a>, used in mining and plastics, respectively. It is more toxic than solid cyanide compounds due to its <a href="/facts/Volatility_(chemistry)/90r3ep6w">volatile</a> nature. A solution of hydrogen cyanide in <a href="/facts/Water_(molecule)/FFsl65l1">water</a>, represented as HCN(<a href="/facts/Aqueous/eRNr3MH2">aq</a>), is called <i>hydrocyanic acid</i>. The <a href="/facts/Salt_(chemistry)/lsSKwGpn">salts</a> of the cyanide anion are known as <a href="/facts/Cyanide/t0o8FMKI">cyanides</a>. </p><p>Whether hydrogen cyanide is an <a href="/facts/Organic_compound/gqCNaN45">organic compound</a> or not is a topic of debate among chemists, and opinions vary from author to author. Traditionally, it is considered <a href="/facts/Inorganic_compound/TfFfzxSz">inorganic</a> by a significant number of authors. Contrary to this view, it is considered organic by other authors, because hydrogen cyanide belongs to the class of organic compounds known as <a href="/facts/Nitriles/Gz7RCnC6">nitriles</a> which have the formula R−C≡N, where R is typically <a href="/facts/Organyl_group/RgeaN5jm">organyl group</a> (e.g., <a href="/facts/Alkyl/vmEk8X4v">alkyl</a> or <a href="/facts/Aryl/M3z7QRXd">aryl</a>) or <a href="/facts/Hydrogen/BoYHjl0J">hydrogen</a>. In the case of hydrogen cyanide, the R group is hydrogen H, so the other names of hydrogen cyanide are methanenitrile and formonitrile. </p>