Hydrogen cyanide in the context of Boiling

Organic compounds are a subclass of chemical compounds of carbon. Little consensus exists among chemists on the exact definition of organic compound; the only universally accepted definition is the quasi-tautological "organic compounds are the subject matter of organic chemistry".

Generally, any large chemical compound containing a carbon–hydrogen or carbon–carbon bond is accepted as an organic compound. Thus alkanes (e.g. ethane, CH₃−CH₃) and their derivatives are typically considered organic. For historical and disciplinary reasons, small molecules containing carbon are generally not accepted: cyanide ion (CN), hydrogen cyanide (HCN), chloroformic acid (ClCO₂H), carbon dioxide (CO₂), and carbonate ion (CO2−3) may all be excluded.

Hydrogen sulfide (preferred IUPAC name and American English) or hydrogen sulphide (Commonwealth English) is a chemical compound with the formula H₂S. It is a colorless hydrogen chalcogenide gas, and is toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist Carl Wilhelm Scheele is credited with having discovered the chemical composition of purified hydrogen sulfide in 1777.

Hydrogen sulfide is toxic to humans and most other animals by inhibiting cellular respiration in a manner similar to hydrogen cyanide. When it is inhaled or its salts are ingested in high amounts, damage to organs occurs rapidly with symptoms ranging from breathing difficulties to convulsions and death. Despite this, the human body produces small amounts of this sulfide and its mineral salts, and uses it as a signalling molecule.

A gas chamber is an apparatus for killing humans or animals with gas, consisting of a sealed chamber into which a poisonous or asphyxiant gas is introduced. Poisonous agents used include hydrogen cyanide and carbon monoxide. High concentration carbon dioxide is typically used in gas chambers for animals.

Triatomic molecules are molecules composed of three atoms, of either the same or different chemical elements. Examples include H₂O, CO₂ (pictured), HCN, O₃ (ozone) and NO₂.

Smoke is an aerosol (a suspension of airborne particulates and gases) emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires (including stoves, candles, internal combustion engines, oil lamps, and fireplaces), but may also be used for pest control (fumigation), communication (smoke signals), defensive and offensive capabilities in the military (smoke screen), cooking, or smoking (tobacco, cannabis, etc.). It is used in rituals where incense, sage, or resin is burned to produce a smell for spiritual or magical purposes. It can also be a flavoring agent and preservative.

Smoke inhalation is the primary cause of death in victims of indoor fires. The smoke kills by a combination of thermal damage, poisoning and pulmonary irritation caused by carbon monoxide, hydrogen cyanide and other combustion products.

The cyano radical (or cyanido radical) is a radical with molecular formula CN, sometimes written CN. The cyano radical was one of the first detected molecules in the interstellar medium, in 1938. Its detection and analysis was influential in astrochemistry. The discovery was confirmed with a coudé spectrograph, which was made famous and credible due to this detection. ·CN has been observed in both diffuse clouds and dense clouds. Usually, CN is detected in regions with hydrogen cyanide, hydrogen isocyanide, and HCNH, since it is involved in the creation and destruction of these species (see also Cyanogen).

The atmosphere of Titan is the dense layer of gases surrounding Titan, the largest moon of Saturn. Titan is the only natural satellite of a planet in the Solar System with an atmosphere that is denser than the atmosphere of Earth and is one of two moons with an atmosphere significant enough to drive weather (the other being the atmosphere of Triton). Titan's lower atmosphere is primarily composed of nitrogen (94.2%), methane (5.65%), and hydrogen (0.099%). There are trace amounts of other hydrocarbons, such as ethane, diacetylene, methylacetylene, acetylene, propane, PAHs and of other gases, such as cyanoacetylene, hydrogen cyanide, carbon dioxide, carbon monoxide, cyanogen, acetonitrile, argon and helium. The isotopic study of nitrogen isotopes ratio also suggests acetonitrile may be present in quantities exceeding hydrogen cyanide and cyanoacetylene. The surface pressure is about 50% higher than on Earth at 1.5 bars (147 kPa). This is higher than the pressure at the triple point of methane, which allows there to be liquid methane on the surface in addition to the gaseous methane in the atmosphere. The orange color as seen from space is produced by other more complex chemicals in small quantities, possibly tholins, tar-like organic precipitates.

Cyanide poisoning is poisoning that results from exposure to any of a number of forms of cyanide. Early symptoms include headache, dizziness, fast heart rate, shortness of breath, and vomiting. This phase may then be followed by seizures, slow heart rate, low blood pressure, loss of consciousness, and cardiac arrest. Onset of symptoms usually occurs within a few minutes. Some survivors have long-term neurological problems.

Toxic cyanide-containing compounds include hydrogen cyanide gas and cyanide salts, such as potassium cyanide. Poisoning is relatively common following breathing in smoke from a house fire. Other potential routes of exposure include workplaces involved in metal polishing, certain insecticides, the medication sodium nitroprusside, and certain seeds such as those of apples and apricots. Liquid forms of cyanide can be absorbed through the skin. Cyanide ions interfere with cellular respiration, resulting in the body's tissues being unable to use oxygen.

The linear molecular geometry describes the geometry around a central atom bonded to two other atoms (or ligands) placed at a bond angle of 180°. Linear organic molecules, such as acetylene (HC≡CH), are often described by invoking sp orbital hybridization for their carbon centers.

According to the VSEPR model (Valence Shell Electron Pair Repulsion model), linear geometry occurs at central atoms with two bonded atoms and zero or three lone pairs (AX₂ or AX₂E₃) in the AXE notation. Neutral AX₂ molecules with linear geometry include beryllium fluoride (F−Be−F) with two single bonds, carbon dioxide (O=C=O) with two double bonds, hydrogen cyanide (H−C≡N) with one single and one triple bond. The most important linear molecule with more than three atoms is acetylene (H−C≡C−H), in which each of its carbon atoms is considered to be a central atom with a single bond to one hydrogen and a triple bond to the other carbon atom. Linear anions include azide (N=N=N) and thiocyanate (S=C=N), and a linear cation is the nitronium ion (O=N=O).

Tetraethylammonium cyanide is the organic compound with the formula [(CH₃CH₂)₄N]CN. It is a "quat salt" of hydrogen cyanide. It consists of tetraethylammonium cations [(CH₃CH₂)₄N] and cyanide anions CN. This salt is a colorless, deliquescent solid that is soluble in polar organic media. It is used in the synthesis of cyanometallates.

Tetraethylammonium cyanide is prepared by ion exchange from tetraethylammonium bromide. The corresponding tetraphenylarsonium salt is prepared similarly.

In organic chemistry, cyanopolyynes are a family of organic compounds with the chemical formula HC_nN (n = 3,5,7,…) and the structural formula H−[C≡C−]_nC≡N (n = 1,2,3,…). Structurally, they are polyynes with a cyano group (−C≡N) covalently bonded to one of the terminal acetylene units (H−C≡C).

A rarely seen group of molecules both due to the difficulty in production and the unstable nature of the paired groups, the cyanopolyynes have been observed as a major organic component in interstellar clouds. This is believed to be due to the hydrogen scarcity of some of these clouds. Interference with hydrogen is one of the reasons for the molecule's instability due to the energetically favorable dissociation back into hydrogen cyanide and acetylene.