Hydrogen cyanide is a linear molecule, with a triple bond between carbon and nitrogen. Hydrogen cyanide is approximately 25 times more toxic than carbon monoxide through the formation of the cyanide ion formed by hydrolysis in the blood. Download preview. [46] Further, the HNC/HCN ratio has been shown to be an excellent method for distinguishing between PDRs and X-ray-dominated regions (XDRs). [47], On 11 August 2014, astronomers released studies, using the Atacama Large Millimeter/Submillimeter Array (ALMA) for the first time, that detailed the distribution of HCN, HNC, H2CO, and dust inside the comae of comets C/2012 F6 (Lemmon) and C/2012 S1 (ISON). In the chemical world, it is a simple molecule, one atom of carbon, one atom of nitrogen and one atom of hydrogen. At further depths, photodissociation by cosmic rays dominate, producing CN (HCN + cr → CN + H). Data compiled as indicated in comments: TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Kenneth Kroenlein director DH - Eugene S. Domalski and Elizabeth D. Hearing AC- William E. Acree, Jr., James S. Chickos [48][49], In February 2016, it was announced that traces of hydrogen cyanide were found in the atmosphere of the hot Super-Earth 55 Cancri e with NASA's Hubble Space Telescope.[50]. Hydrogen cyanide has been absorbed into a carrier for use as a pesticide. Hydrogen cyanide is used primarily in the production of substances such as adiponitrile, methyl methacrylate, chelating agents, cyanuric chloride, methionine and its hydroxylated analogues, and sodium and potassium cyanide. Hydrogen cyanide or Formonitrile is a chemical compound with the chemical formula HCN. Hydrogen cyanide (HCN), also known as hydrocyanic acid, is a colorless gas or liquid with a characteristic faint odor of bitter almonds. The dissociative recombination pathway is dominant by 30%; however, the HCNH+ must be in its linear form. HCN is destroyed in interstellar clouds through a number of mechanisms depending on the location in the cloud. [32], The vasodilatation caused by sodium nitroprusside has been shown to be mediated not only by NO generation, but also by endogenous cyanide generation, which adds not only toxicity, but also some additional antihypertensive efficacy compared to nitroglycerine and other non-cyanogenic nitrates which do not cause blood cyanide levels to rise. In English, it became known popularly as prussic acid. In this paper we explore the atmospheric behavior of HCN by examining its chemical and photochemical properties. Hydrogen cyanide, sometimes called prussic acid, is a chemical compound[8] with the chemical formula HCN. Royalty-Free Illustration. Answer to: Write the Lewis structures for the following compound: Hydrogen cyanide (HCN). [53] A hydrogen cyanide concentration of 2000 ppm (about 2380 mg/m3) will kill a human in about one minute. They have also shown that neuronal production of HCN activates NMDA receptors and plays a role in signal transduction between neuronal cells (neurotransmission). [29][30] Ultraviolet radiation breaks HCN up into CN + H; however, CN is efficiently recycled back into HCN via the reaction CN + CH4 → HCN + CH3. Cyanide is also found in combustion products of x-ray film, wool, silk, nylon, paper, ... Other heterocyclic structures like indoloquinazolines were also obtained via the elimination of HCN by treatment with DBU <2002RCB(E)1869>. Hydrogen cyanide was first isolated from a blue pigment (Prussian blue) which had been known since 1704 but whose structure was unknown.It is now known to be a coordination polymer with a complex structure and an empirical formula of hydrated ferric ferrocyanide. HCN has been used to analyze a variety of species and processes in the interstellar medium. The large demand for cyanides for mining operations in the 1890s was met by George Thomas Beilby, who patented a method to produce hydrogen cyanide by passing ammonia over glowing coal in 1892. HCN has a faint bitter almond-like odor that some people are unable to detect owing to a recessive genetic trait. [54] It is listed under Schedule 3 of the Chemical Weapons Convention as a potential weapon which has large-scale industrial uses; manufacturing plants in signatory countries that produce more than 30 metric tons per year must be declared to, and can be inspected by, the Organisation for the Prohibition of Chemical Weapons. Except where otherwise noted, data are given for materials in their, CS1 maint: multiple names: authors list (, Macquer, Pierre-Joseph (presented: 1752; published: 1756), Berthollet, C. L. (presented: 1787 ; published: 1789), Atacama Large Millimeter/Submillimeter Array (ALMA), Organisation for the Prohibition of Chemical Weapons, National Institute for Occupational Safety and Health, Ullmann's Encyclopedia of Industrial Chemistry, "Wolfram-Alpha: Computational Knowledge Engine", "Försök, beträffande det färgande ämnet uti Berlinerblå", "De materia tingente caerulei berolinensis", "Extrait d'un mémoire sur l'acide prussique", "Claude Louis Berthollet: A Great Chemist in the French Tradition", Non-confidential 2006 IUR Records by Chemical, including Manufacturing, Processing and Use Information, "Cyanogenesis in Cassava, The Role of Hydroxynitrile Lyase in Root Cyanide Production", "HCN Production in Titan's Atmosphere: Coupling Quantum Chemistry and Disequilibrium Atmospheric Modeling", "Making Sense of the Chemistry That Led to Life on Earth", "Submillimeter‐ and Millimeter‐Wavelength Observations of SiO and HCN in Circumstellar Envelopes of AGB Stars", "RELEASE 14-038 – NASA's 3-D Study of Comets Reveals Chemical Factory at Work", "First detection of super-earth atmosphere", "Documentation for Immediately Dangerous to Life or Health Concentrations (IDLHs) – 74908", Cyanure d'hydrogène et solutions aqueuses, National Pollutant Inventory: Cyanide compounds fact sheet, Octamethylene-bis(5-dimethylcarbamoxyisoquinolinium bromide), 2-Ethoxycarbonyl-1-methylvinyl cyclohexyl methylphosphonate, https://en.wikipedia.org/w/index.php?title=Hydrogen_cyanide&oldid=1004806286, Articles with changed ChemSpider identifier, Pages using collapsible list with both background and text-align in titlestyle, Articles containing unverified chemical infoboxes, Articles containing Ancient Greek (to 1453)-language text, All articles with specifically marked weasel-worded phrases, Articles with specifically marked weasel-worded phrases from December 2020, All articles with vague or ambiguous time, Vague or ambiguous time from October 2020, Articles with unsourced statements from April 2020, Creative Commons Attribution-ShareAlike License, Institut national de recherche et de sécurité (1997). Hydrogen bond polymerization of the gas in chains of indefinite length, J. I. [43] In photon-dominated regions (PDRs), photodissociation dominates, producing CN (HCN + ν → CN + H). ", This page was last edited on 4 February 2021, at 14:01. It is colorless light low boiling liquid; associated by hydrogen bonds (at room temperature the degree of … HCN is formed in interstellar clouds through one of two major pathways:[43] via a neutral-neutral reaction (CH2 + N → HCN + H) and via dissociative recombination (HCNH+ + e− → HCN + H). Hydrogen cyanide is contained in the exhaust of vehicles, and in smoke from burning nitrogen-containing plastics. Hey Guys !In this video we are going to learn the Lewis Structure of Hydrogen Cyanide. CopyCopied, LELOWRISYMNNSU-UHFFFAOYSA-N [17] The radical cyanide in hydrogen cyanide was given its name from cyan, not only an English word for a shade of blue but the Greek word for blue (Ancient Greek: κύανος), again owing to its derivation from Prussian blue. Heat capacity, heat of vaporization and vapor pressure. It has been suggested as a tracer for dense molecular gas[44][45] and as a tracer of stellar inflow in high-mass star-forming regions. 6 Two mechanisms have been identified for the toxic effects of cyanide. As such, hydrogen cyanide is commonly listed among chemical weapons as a blood agent. [37], HCN has been detected in the interstellar medium[38] and in the atmospheres of carbon stars. Hydrogen cyanide is a colourless or pale blue liquid or gas with a faint bitter almond-like odour. [9] HCN is produced on an industrial scale and is a highly valuable precursor to many chemical compounds ranging from polymers to pharmaceuticals. propane, are reacted with ammonia. Following Macquer's lead, it was first prepared from Prussian blue by the Swedish chemist Carl Wilhelm Scheele in 1782,[13] and was eventually given the German name Blausäure (lit. As Carbon is bonded to two atoms, it follows the molecular geometry of AX2. Hydrogen cyanide is a linear molecule, with a triple bond between carbon and nitrogen. These properties combine to make its use in the field impractical. In the dark core, two competing mechanisms destroy it, forming HCN+ and HCNH+ (HCN + H+ → HCN+ + H; HCN + HCO+ → HCNH+ + CO). One of the original Czech producers continued making Zyklon B under the trademark "Uragan D2"[56] until recently.[when?] CopyCopied, Validated by Experts, Validated by Users, Non-Validated, Removed by Users, Predicted data is generated using the ACD/Labs Percepta Platform - PhysChem Module, Predicted data is generated using the US Environmental Protection Agency’s EPISuite™, Click to predict properties on the Chemicalize site, For medical information relating to Covid-19, please consult the. [31], Some authors[who?] [11] Cyanide ions interfere with iron-containing respiratory enzymes. Hydrogen cyanide is a linear molecule, with a triple bond between carbon and nitrogen. : TWA 10 ppm (11 mg/m 3 ) [skin], A one-carbon compound consisting of a methine group triple bonded to a nitrogen atom. The molecular structure is based on structures generated from information available in ECHA’s databases. In 1752, the French chemist Pierre Macquer made the important step of showing that Prussian blue could be converted to an iron oxide plus a volatile component and that these could be used to reconstitute it. Royalty-Free Illustration. In the Shawinigan Process, hydrocarbons, e.g. Hydrogen cyanide molecular structure isolated on white. Chromatogr., 481, 1989, 45-54. ass: Standard non-polar; Column type: Capillary; CAS no: 74908; Active phase: Polydimethyl siloxane; Data type: Normal alkane RI; Authors: Staples, E.J., Creating a compound library for chemical warfare agents for the ZNose, 2006. [34], HCN is a constituent of tobacco smoke. In 1787, the French chemist Claude Louis Berthollet showed that prussic acid did not contain oxygen,[14] an important contribution to acid theory, which had hitherto postulated that acids must contain oxygen[15] (hence the name of oxygen itself, which is derived from Greek elements that mean "acid-former" and are likewise calqued into German as Sauerstoff). Cyanamide is a nitrile that is hydrogen cyanide in which the hydrogen has been replaced by an amino group. [18], The most important process is the Andrussow oxidation invented by Leonid Andrussow at IG Farben in which methane and ammonia react in the presence of oxygen at about 1,200 °C (2,190 °F) over a platinum catalyst:[19]. have shown that neurons can produce hydrogen cyanide upon activation of their opioid receptors by endogenous or exogenous opioids. HCN - HYDROGEN CYANIDE. [23] Some millipedes release hydrogen cyanide as a defense mechanism,[24] as do certain insects, such as some burnet moths. Perhaps the most infamous of these is Zyklon B (German: Cyclone B, with the B standing for Blausäure – prussic acid; also, to distinguish it from an earlier product later known as Zyklon A),[55] it was used in Nazi German extermination camps during World War II to kill en masse as part of their Final Solution genocide program. Soc., 1939, 61, 2626-2633. Hydrogen adsorption on cyanide-modified Pt(1 1 1) surfaces Hence Hydrogen Cyanide has linear molecular geometry. ], Skin: Prevent skin contact Eyes: Prevent eye contact Wash skin: When contaminated Remove: When wet (flammable) Change: No recommendation Provide: Eyewash, Quick drench, NIOSH REL : ST 4.7 ppm (5 mg/m 3 ) [skin] OSHA PEL ? It is a colorless, extremely poisonous and flammable liquid that boils slightly above room temperature, at 25.6 °C (78.1 °F). It is a highly toxic substance that interferes with energy pro-duction in our cells. "Blue acid") because of its acidic nature in water and its derivation from Prussian blue. Hydrogen cyanide is a colorless gas with a faint, bitter, almondlike odor. And as per VSEPR theory, molecules covered under AX2 have a linear molecular geometry. [25][26], HCN has been measured in Titan's atmosphere by four instruments on the Cassini space probe, one instrument on Voyager, and one instrument on Earth. So-called "bitter" roots of the cassava plant may contain up to 1 gram of HCN per kilogram. It is a conjugate acid of a cyanamide(2-). [51][52] The gas is lighter than air and rapidly disperses up into the atmosphere; this is in contrast to denser agents such as phosgene or chlorine which tend to remain at ground level and sink into the trenches of the Western Front's battlefields. [8] In 2006 between 500 million and 1 billion pounds (between 230,000 and 450,000 t) were produced in the US. The energy needed for the reaction is provided by the partial oxidation of methane and ammonia. [29], It has been postulated that carbon from a cascade of asteroids (known as the Late Heavy Bombardment), resulting from interaction of Jupiter and Saturn, blasted the surface of young Earth and reacted with nitrogen in Earth's atmosphere to form HCN. In the laboratory, small amounts of HCN are produced by the addition of acids to cyanide salts of alkali metals: This reaction is sometimes the basis of accidental poisonings because the acid converts a nonvolatile cyanide salt into the gaseous HCN. It is now known to be a coordination polymer with a complex structure and an empirical formula of hydrated ferric ferrocyanide. Dissociative recombination with its structural isomer, H2NC+, exclusively produces hydrogen isocyanide (HNC). A cyanide is a chemical compound that contains the group C≡N. Hydrogen cyanide molecular structure isolated on grey. [16] In 1815, Gay-Lussac deduced Prussic acid's chemical formula. It is a colorless, extremely poisonous and flammable liquid that … It was distilled once through calcium chloride and phosphorus pentoxide and once under vacuum. Procedure/Use Scale Engineering Controls/Equipment PPE (eye, face, gloves, clothing) Procedure Steps and Precautions 3. Hydrogen cyanide (HeN)is a colorless, odorless gas. [27] One of these measurements was in situ, where the Cassini spacecraft dipped between 1,000 and 1,100 km (620 and 680 mi) above Titan's surface to collect atmospheric gas for mass spectrometry analysis. Hydrogen Cyanide Chemical Specific Standard Operating Procedure Rev. Analysis of low-molecular-weight hydrocarbons and nitriles with a CP-Sil-5 CB WCOT capillary column, J. HCN concentrations (volume mixing ratios) of (1.5–1.7) × 10 −10 appear to characterize the stratosphere and the northern hemisphere's nonurban troposphere. Hydrogen Cyanide has geometry like AX2 molecule, where A is the central atom and X is the number of atoms bonded with the central atom. It is a nitrile and a one-carbon compound. Under the name prussic acid, HCN has been used as a killing agent in whaling harpoons, although it proved quite dangerous to the crew deploying it, and thus it was quickly abandoned. Chem. [12] The new component was what is now known as hydrogen cyanide. Moreover, increased endogenous neuronal HCN production under opioids was seemingly needed for adequate opioid analgesia, as analgesic action of opioids was attenuated by HCN scavengers. Hydrogen cyanide gas is produced in blast furnaces, gas works, and coke ovens. [10] The volatile compound has been used as inhalation rodenticide and human poison, as well as for killing whales. It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at 25.6 °C (78.1 °F). Of lesser importance is the Degussa process (BMA process) in which no oxygen is added and the energy must be transferred indirectly through the reactor wall:[20]. ACD/Labs Percepta Platform - PhysChem Module, US Environmental Protection Agency’s EPISuite™, Compounds with the same molecular formula, Search Google for structures with same skeleton, Colorless or pale-blue liquid or gas (above 78F) with a bitter, almond-like odor. Compared to such agents it must also be present in higher concentrations in order to be fatal. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom.. The reaction with HCO+ dominates by a factor of ~3.5. It partially ionizes in water solution to give the cyanide anion, CN−. It has a role as an EC 1.2.1.3 [aldehyde dehydrogenase (NAD(+))] inhibitor. HCN is produced on an industrial scale and is a highly valuable precursor to many chemical compounds ranging from polymers to pharmaceuticals. Analysis of low-molecular-weight hydrocarbons and nitriles with a PoraPLOT Q porous polymer coated open-tubular capillary column, J. They considered endogenous HCN to be a neuromodulator. Go To: Top, References, Notes Data compilation copyrightby the U.S. Secretary of Commerce on behalf of the U.S.A.All rights reserved. ... HYDROCYANIC ACID, AQUEOUS SOLUTION (HYDROGEN CYANIDE, AQUEOUS SOLUTION) with not more than 20% hydrogen cyanide . … But this little guy packs one heck of a punch! [8], HCN is obtainable from fruits that have a pit, such as cherries, apricots, apples, and bitter almonds, from which almond oil and flavoring are made. Molecular structure. Salts such as sodium cyanide and potassium cyanide are highly toxic. Hydrogen cyanide is a colorless, extremely poisonous liquid that boils slightly above room temperature at 26 °C (79 °F). 3.2. HCN is the precursor to sodium cyanide and potassium cyanide, which are used mainly in gold and silver mining and for the electroplating of those metals. Experimental Pure anhydrous hydrogen cyanide was prepared by dropping 18 M-sulfuric acid on solid sodium cyanide and condensing the gas after it had passed through a drying line. Hydrogen cyanide or Formonitrile is a chemical compound with the chemical formula HCN. Hydrogen cyanide is a very small, linear molecule. III. Hydrogen cyanide forms in at least limited amounts from many combinations of hydrogen, carbon, and ammonia. Adenine). This reaction is akin to steam reforming, the reaction of methane and water to give carbon monoxide and hydrogen. 10 Unlike carbon monoxide which remains primarily in the blood (as COHb), the cyanide ion is distributed throughout the extracellular fluid of tissues and organs. Am. A minor tautomer of HCN is HNC, hydrogen isocyanide. [36] Although the relationship of these chemical reactions to the origin of life theory remains speculative, studies in this area have led to discoveries of new pathways to organic compounds derived from the condensation of HCN (e.g. The salts of the cyanide anion are known as cyanides. As for the zig-zag structure, although the cavity in this case is quite similar to that of the experimentally observed structure, in the presence of counter-ions the CN groups probably tend to rearrange, rendering a distribution less stable than the (2 3 × 2 3) structure. Hydrogen cyanide is currently produced in great quantities by several processes, as well as being a recovered waste product from the manufacture of acrylonitrile. Structure, properties, spectra, suppliers and links for: Hydrogen cyanide. Via the hydrocyanation process, HCN is added to butadiene to give adiponitrile, a precursor to Nylon-6,6. [21][22] One hundred grams of crushed apple seeds can yield about 70 mg of HCN. [28] HCN initially forms in Titan's atmosphere through the reaction of photochemically produced methane and nitrogen radicals which proceed through the H2CN intermediate, e.g., (CH3 + N → H2CN + H → HCN + H2). ], Organic Compound; Cyanide Compound; Nitrile; Pollutant; Food Toxin; Metabolite; Industrial/Workplace Toxin; Natural Compound, Eye: Irrigate immediately Skin: Water flush immediately Breathing: Respiratory support Swallow: Medical attention immediately, inhalation, skin absorption, ingestion, skin and/or eye contact, Asphyxia; lassitude (weakness, exhaustion), headache, confusion; nausea, vomiting; increased rate and depth of respiration or respiration slow and gasping; thyroid, blood changes, central nervous system, cardiovascular system, thyroid, blood, Amines, oxidizers, acids, sodium hydroxide, calcium hydroxide, sodium carbonate, caustics, ammonia [Note: Can polymerize at 122-140F. Cyanide and hydrogen cyanide are used in electroplating, metallurgy, organic chemicals production, photographic developing, manufacture of plastics, fumigation of ships, and some mining processes. [33], Leukocytes generate HCN during phagocytosis, and can kill bacteria, fungi, and other pathogens by generating several different toxic chemicals, one of which is hydrogen cyanide. The carbon atom is connected to the nitrogen by a strong triple bond, whereas the hydrogen is much more weakly attached. A solution of hydrogen cyanide in water, represented as HCN, is called hydrocyanic acid. [53] The toxicity is caused by the cyanide ion, which halts cellular respiration by acting as a non-competitive inhibitor for an enzyme in mitochondria called cytochrome c oxidase. A minor tautomer of HCN is HNC, hydrogen isocyanide. Bond formation, hydrogen cyanide molecule. It is a relative dwarf in the world of organic chemistry. [40] The J=1→0, J=3→2, J= 4→3, and J=10→9 pure rotational transitions have all been observed.[38][41][42]. [35], Hydrogen cyanide has been discussed as a precursor to amino acids and nucleic acids, and is proposed to have played a part in the origin of life. Hydrogen cyanide (HCN), sometimes called prussic acid, is a chemical compound with the chemical formula HCN. Since 1981, three groups have reported spectroscopic detections and measurements of hydrogen cyanide in the atmosphere. Hydrogen cyanide. , The entropy of hydrogen cyanide. Cyanide (as hydrogen cyanide), originating in vivo by dissociation of potassium cyanide, sodium cyanide, and other cyanogenic compounds or arising from catabolism of cyanogenic glycosides, exerts its acute toxic effects by complexing with the ferric iron atom in metalloenzymes, resulting in histotoxic anoxia through inhibition of cytochrome c oxidase, metalloenzymes that function as the terminal oxidase of … [39] Since then, extensive studies have probed formation and destruction pathways of HCN in various environments and examined its use as a tracer for a variety of astronomical species and processes. Many of these pits contain small amounts of cyanohydrins such as mandelonitrile and amygdalin, which slowly release hydrogen cyanide. Chromatogr., 591, 1992, 297-301. umn class: Semi-standard non-polar; Column diameter: 0.32 mm; Column length: 10 m; Column type: Capillary; Start T: 160 C; CAS no: 74908; Active phase: PoraPLOT Q; Carrier gas: H2; Phase thickness: 10 um; Data type: Kovats RI; Authors: Do, L.; Raulin, F., Gas chromatography of Titan's atmosphere. It is a colorless, extremely poisonous and flammable liquid that … Hydrogen cyanide was also used in the camps for delousing clothing in attempts to eradicate diseases carried by lice and other parasites. It is simply H-C-N. Hydrogen cyanide gas in air is explosive at concentrations over 5.6%. Hydrogen cyanide was first isolated from a blue pigment (Prussian blue) which had been known since 1706, but whose structure was unknown. Download preview. Molecular Formula CHN; Average mass 27.025 Da; Monoisotopic mass 27.010899 Da; ChemSpider ID 748 [58] This is far above its toxicity level. In 1811, Joseph Louis Gay-Lussac prepared pure, liquified hydrogen cyanide. In World War I, hydrogen cyanide was used as a chemical weapon against the Central Powers by the French from 1916, and by the United States and Italy in 1918, but it was not found to be effective enough due to weather conditions. [32], It has also been shown that, while stimulating muscarinic cholinergic receptors in cultured pheochromocytoma cells increases HCN production, in a living organism (in vivo) muscarinic cholinergic stimulation actually decreases HCN production. Date: 09Sept2016 10 Notes Any deviation from this SOP requires approval from PI. Draw the Lewis dot structure of Hydrogen cyanide (HCN) molecule . [11] From the middle of the 18th century it was used in a number of poisoning murders and suicides.[57]. Illustration of the sharing of electrons (dots and crosses) between a hydrogen (H), carbon (C) and nitrogen (N) atom to form a molecule of hydrogen cyanide … In inorganic cyanides, the cyanide group is present as the anion CN −. A hydrogen cyanide concentration in the range of 100–200 ppm in air will kill a human within 10 to 60 minutes. Hydrogen cyanide was also the agent employed in judicial execution in some U.S. states, where it was produced during the execution by the action of sulfuric acid on sodium or potassium cyanide. Hydrogen cyanide(with the historical common name of Prussic acid) is a chemical compound with chemical formula HCN. Via the intermediacy of cyanohydrins, a variety of useful organic compounds are prepared from HCN including the monomer methyl methacrylate, from acetone, the amino acid methionine, via the Strecker synthesis, and the chelating agents EDTA and NTA. HCN can be observed from ground-based telescopes through a number of atmospheric windows. This method was used until Hamilton Castner in 1894 developed a synthesis starting from coal, ammonia, and sodium yielding sodium cyanide, which reacts with acid to form gaseous HCN. CopyCopied, CSID:748, http://www.chemspider.com/Chemical-Structure.748.html (accessed 21:47, Feb 13, 2021) umn class: Standard non-polar; Column diameter: 0.15 mm; Column length: 25 m; Column type: Capillary; Start T: 20 C; CAS no: 74908; Active phase: CP Sil 5 CB; Carrier gas: H2; Phase thickness: 2 um; Data type: Kovats RI; Authors: Do, L.; Raulin, F., Gas chromatography of Titan's atmosphere. Hydrogen cyanide, also called formonitrile (HCN), a highly volatile, colourless, and extremely poisonous liquid (boiling point 26° C [79° F], freezing point-14° C [7° F]).A solution of hydrogen cyanide in water is called hydrocyanic acid, or prussic acid.It was discovered in 1782 by a Swedish chemist, Carl Wilhelm Scheele, who prepared it from the pigment Prussian blue. Sodium cyanide and potassium cyanide are both white solids with a bitter, almond- like odor in damp air. [Note: Often used as a 96% solution in water. In molecular clouds, formation of formyl cyanide is speculated to result from formaldehyde and the cyanide radical: CH 2 O + CN • → HCOCN + H • In Earth's atmosphere, the pollutant acrylonitrile reacts with hydroxyl radical forming formyl cyanide, hydroperoxyl and formaldehyde: CH 2 =CHCN + OH • + 1.5 O 2 → HO 2 + HCOCN + CH 2 O Reactions