What is cyanide in a chemical context, and what defines the cyano group?

In chemistry, cyanide is an inorganic compound characterized by the presence of a cyano group. This functional group consists of a carbon atom triple-bonded to a nitrogen atom (C≡N).

What is the chemical formula and charge of the cyanide anion?

The cyanide anion has the chemical formula CN⁻, signifying a carbon atom triple-bonded to a nitrogen atom, carrying an overall negative charge.

What is the systematic IUPAC name for cyanide?

The systematic IUPAC name for cyanide is Nitridocarbonate(II).

What is the molar mass of the cyanide ion?

The molar mass of the cyanide ion is approximately 26.018 grams per mole.

What are the primary hazards associated with the cyanide ion?

The cyanide ion is exceptionally poisonous and can lead to death within minutes of exposure.

How does the cyanide ion's electronic structure compare to carbon monoxide and molecular nitrogen?

The cyanide ion (CN⁻) is isoelectronic with carbon monoxide (CO) and molecular nitrogen (N₂), meaning they share the same number of electrons and exhibit similar bonding, including a triple bond between the constituent atoms.

Where is the negative charge concentrated within the cyanide ion?

In the cyanide ion (CN⁻), the negative charge is primarily concentrated on the carbon atom.

Does cyanide occur naturally, and in what forms?

Yes, cyanides are naturally produced by various organisms, including insects, bacteria, fungi, and algae. They are also found in certain plant seeds and fruit stones, such as those of bitter almonds, apricots, apples, and peaches, often in the form of cyanogenic glycosides.

What is the function of cyanogenic glycosides in plants?

Cyanogenic glycosides are compounds found in plants that can release cyanide. They act as a defense mechanism, serving as an antifeedant to deter herbivores from consuming the plant.

What is cassava, and how is it related to cyanogenic glycosides?

Cassava, also known as manioc, is a vital root vegetable staple in tropical regions. Its roots contain cyanogenic glycosides, necessitating proper processing to remove the toxic cyanide before consumption.

In which biological molecules can cyanide ligands be found?

Cyanide can be found as ligands attached to iron atoms within the active sites of certain enzymes, notably hydrogenases, such as the NiFe hydrogenases.

Has cyanide been detected in interstellar space?

Yes, the cyanide radical (•CN) has been identified in interstellar space. Additionally, cyanogen (CN)₂ is utilized to measure the temperature of interstellar gas clouds.

Under what conditions is hydrogen cyanide (HCN) produced during combustion or pyrolysis?

Hydrogen cyanide is generated when materials containing both carbon and nitrogen undergo combustion or pyrolysis in environments with limited oxygen. Examples include the burning of certain plastics and tobacco smoke.

What are organic compounds containing the -C≡N functional group called?

Organic compounds that feature the -C≡N functional group are classified as nitriles.

How does the toxicity of cyanohydrins differ from that of typical nitriles?

Unlike most nitriles, cyanohydrins possess both a hydroxyl (-OH) and a cyano (-CN) group attached to the same carbon atom. This structure allows them to release poisonous hydrogen cyanide, making them toxic.

What is the basicity of cyanide, and what reaction occurs when acids are added to cyanide salts?

Cyanide is basic, with hydrogen cyanide having a pKa of 9.21. When acids stronger than hydrogen cyanide are added to solutions containing cyanide salts, toxic hydrogen cyanide gas is released.

Describe the hydrolysis of cyanide in water.

Cyanide is unstable in water and undergoes hydrolysis, albeit slowly at room temperature, to produce ammonia and formate. These resulting compounds are considerably less toxic than cyanide. The enzyme cyanide hydrolase catalyzes this reaction.

How is the cyano group typically introduced into organic molecules during synthesis?

Due to the cyanide anion's potent nucleophilicity, it is commonly employed in organic synthesis to introduce cyano groups by displacing halide groups from organic molecules, effectively extending carbon chains.

What is the role of cyanide in redox reactions?

The cyanide ion functions as a reductant and can be oxidized by strong oxidizing agents like chlorine or hydrogen peroxide. These oxidizing agents are utilized to eliminate cyanide from industrial wastewater.

How does cyanide interact with transition metals, and why is this interaction significant?

The cyanide anion forms strong bonds with transition metals, creating M-CN bonds. This strong affinity is the primary reason for cyanide's toxicity, as it can interfere with essential metalloenzymes in biological systems, disrupting cellular functions.

What are some notable cyanide coordination compounds, and why are they considered less toxic?

Potassium ferrocyanide and Prussian blue are significant cyanide coordination compounds. They exhibit lower toxicity because the cyanide ions are tightly bound to the central iron atom, preventing their easy release.

How is sodium cyanide typically manufactured from hydrogen cyanide?

Sodium cyanide is commonly produced by reacting hydrogen cyanide with sodium hydroxide.

Which human tissues are most vulnerable to cyanide poisoning and why?

Tissues with high energy demands that rely heavily on aerobic respiration, such as the central nervous system and the heart, are particularly susceptible to cyanide poisoning. This is because they require a continuous supply of ATP, which is directly impacted by the inhibition of cellular respiration.

What are the risks associated with hydrogen cyanide gas, and what safety precautions are necessary?

Hydrogen cyanide is a volatile and highly toxic gas that can be lethal if inhaled. Handling it requires the use of an air respirator supplied with an external oxygen source to prevent exposure.

Why are alkaline cyanide solutions considered safer to handle than acidic ones?

Alkaline solutions of cyanide are safer because they do not readily release hydrogen cyanide gas, unlike acidic solutions which can liberate this toxic vapor into the air.

What are the common methods for disposing of cyanide waste?

Cyanide waste is typically managed through oxidation using agents like peroxysulfuric acid or hydrogen peroxide, hydrolysis at elevated temperatures, or acidification to recover hydrogen cyanide.

What is the role of hydroxocobalamin in treating cyanide poisoning?

Hydroxocobalamin serves as an antidote for cyanide poisoning by reacting with cyanide ions to form cyanocobalamin (a form of Vitamin B12), which can be safely excreted by the kidneys.

Can you describe the older methods used for cyanide poisoning antidotes?

Older antidote protocols involved inhaling amyl nitrite, followed by intravenous administration of sodium nitrite to convert hemoglobin to methemoglobin (which binds cyanide), and sodium thiosulfate to aid the enzyme rhodanese in converting cyanide to thiocyanate.

What is the function of the rhodanese enzyme in the body's response to cyanide?

Rhodanese is a mitochondrial enzyme that detoxifies cyanide by converting it into the less harmful thiocyanate, utilizing sulfur donors like thiosulfate.

What potential health issues can arise from repeated, low-level exposure to cyanide?

Repeated exposure to sublethal amounts of cyanide may lead to health problems such as hypersensitivity, asthma, or bronchitis, which might not be adequately addressed by standard minimum risk levels.

What is the primary application of cyanide in the mining sector?

Cyanide is predominantly used in the mining industry for the extraction of gold and silver. It facilitates the dissolution of these precious metals by forming soluble complexes, allowing for their separation from the ore.

How does the cyanide process aid in extracting gold and silver from ore?

In the cyanide process, cyanide solutions are used to dissolve gold and silver from finely ground ore by forming soluble complexes like dicyanoargentate(I) and dicyanoaurate(I), which are then separated from the remaining solid material.

What are the environmental concerns associated with using cyanide in gold mining?

Environmental issues include the potential for cyanide contamination of waterways through spills or tailing pond overflows, which can harm aquatic life and humans, and the possibility of mobilizing heavy metals like mercury.

Besides mining, what is another significant industrial use for alkali metal cyanides?

Another major industrial application involves the production of organic compounds, particularly nitriles, as well as other chemicals containing the cyano group, such as cyanogen and cyanuric chloride.

What are some medical applications involving cyanide compounds?

Sodium nitroprusside, a cyanide compound, is used in clinical chemistry for measuring urine ketone bodies and as a rapid hypotensive agent. Additionally, the purification of Vitamin B₁₂ can involve a cyanide ligand.

In what illegal activities is cyanide sometimes employed?

Cyanides are illegally used in methods such as cyanide fishing to capture live fish for the aquarium trade and to poison waterholes, tragically resulting in the deaths of elephants for their ivory.

Provide examples of cyanide's use in pest control.

Cyanide is utilized in M44 devices in the United States to control coyotes and other canids. In New Zealand, it is employed for pest management, targeting possums and wallabies. Cyanide salts also function as insecticides for ship fumigation and were historically used as rat poison.

Can cyanide have any beneficial effects in plant biology?

Interestingly, cyanide and cyanohydrins have been observed to promote seed germination in various plant species.

How are ferrocyanides utilized in the food industry?

Ferrocyanides, such as sodium ferrocyanide (E535) and potassium ferrocyanide (E536), are used as anticaking agents in table salt. Their effectiveness stems from the stable complex formed with iron, which prevents the release of toxic cyanide levels.

What are some chemical methods used to detect cyanide?

Cyanide can be quantified through potentiometric titration or titration with silver ions. Qualitative detection methods include the formation of Prussian blue with iron(II) sulfate or a fluorescent reaction using p-benzoquinone.

What is Prussian blue, and what are its historical applications?

Prussian blue is a cyanide coordination compound known for its stability and relative non-toxicity due to the strong binding of cyanide to iron. Historically, it has been used as a pigment in blueprints, bluing agents, and cyanotypes.

What is the significance of the pKa value of hydrogen cyanide?

The pKa of hydrogen cyanide is 9.21, indicating its weakly acidic nature. This property means that adding acids stronger than HCN to cyanide salts will result in the liberation of HCN gas.

What is the difference in toxicity between organic nitriles and cyanohydrins?

Organic nitriles are generally less toxic as they do not readily release cyanide ions. In contrast, cyanohydrins, which contain both a hydroxyl and a cyano group on the same carbon atom, can release hydrogen cyanide and are therefore toxic.

What role does sodium thiosulfate play in cyanide antidote kits?

Sodium thiosulfate serves as a sulfur donor for the rhodanese enzyme. This enzyme is vital for converting cyanide into the less toxic thiocyanate, thereby accelerating the body's detoxification process.

Why is hydrogen cyanide gas considered ineffective as a chemical weapon?

Although highly toxic, hydrogen cyanide gas is lighter than air and disperses quickly into the atmosphere, which limits its potential effectiveness as a chemical weapon.

What is the primary application of cyanide in industrial organic chemistry?

The main application of cyanide in industrial organic chemistry is the synthesis of nitriles and other compounds containing the cyano group.

What historical medical use has been documented for copper cyanide?

During World War I, copper cyanide compounds were briefly administered by Japanese physicians as a treatment for tuberculosis and leprosy.

What are M44 cyanide devices used for in the United States?

In the United States, M44 cyanide devices are utilized for pest control, specifically targeting coyotes and other canids.

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Cyanide: Fundamental Concepts

Chemical Identity

In chemistry, cyanide refers to an inorganic compound containing the cyano functional group (C≡N). This group consists of a carbon atom triple-bonded to a nitrogen atom. Ionic cyanides contain the cyanide anion ([C≡N]⁻), which is exceptionally poisonous and can cause death rapidly upon exposure.

Natural Occurrence

Cyanides are naturally produced by various organisms, including certain insects, bacteria, fungi, and algae. They are found in significant quantities within the seeds and fruit stones of plants like bitter almonds, apricots, apples, and peaches, often bound to sugar molecules as cyanogenic glycosides, serving as a defense mechanism against herbivores. Cassava roots, a staple food in many tropical regions, also contain these compounds.

Combustion Product

Hydrogen cyanide (HCN) is generated during the combustion or pyrolysis of specific materials under oxygen-deficient conditions. It can be detected in the exhaust fumes of internal combustion engines and in tobacco smoke. Certain plastics, particularly those derived from acrylonitrile, release HCN when heated or burned.

The Cyanide Bond

Molecular Structure

The cyanide ion ([C≡N]⁻) is isoelectronic with carbon monoxide (CO) and molecular nitrogen (N₂). It features a strong triple bond between the carbon and nitrogen atoms. The overall negative charge is primarily localized on the carbon atom, contributing to its nucleophilic character.

Cyanide's Presence

Biological Origins

Cyanide compounds are synthesized by a diverse range of life forms. Plants utilize cyanogenic glycosides as a defense against herbivores. Notably, the Madagascar bamboo produces cyanide, to which the golden bamboo lemur has developed a remarkable tolerance.

Interstellar Medium

The cyanide radical (•CN) has been detected in interstellar space. Cyanogen ((CN)₂) is utilized by astronomers to measure the temperature of interstellar gas clouds, providing insights into the conditions within these cosmic environments.

Combustion Byproduct

Hydrogen cyanide is a known byproduct of incomplete combustion. It is found in vehicle exhaust and tobacco smoke. Materials like acrylonitrile-based plastics release HCN upon combustion, posing a significant hazard in fire situations.

Organic Cyanide Derivatives

Nitriles and Cyanohydrins

Organic compounds featuring the cyano functional group (−C≡N) are classified as nitriles according to IUPAC nomenclature. Acetonitrile (CH₃−C≡N) is a common example. Generally, nitriles exhibit low toxicity as they do not readily release cyanide ions. However, cyanohydrins, which possess both a hydroxyl (−OH) and a cyano (−CN) group attached to the same carbon atom, can release toxic hydrogen cyanide.

Chemical Reactivity

Hydrolysis and Protonation

Cyanide is a basic anion (pKa of HCN is 9.21). Addition of strong acids readily protonates cyanide, releasing highly volatile and toxic hydrogen cyanide gas. While cyanide is unstable in water, hydrolysis to ammonia and formate occurs slowly at ambient temperatures but accelerates significantly at higher temperatures.

Redox and Complexation

The cyanide ion acts as a reductant, being oxidized by strong oxidizing agents like chlorine or hydrogen peroxide. This reactivity is exploited in industrial effluent treatment. Cyanide exhibits a high affinity for transition metals, forming stable coordination complexes (e.g., [Ag(CN)₂]⁻, [Au(CN)₂]⁻). This strong binding is the fundamental basis of its potent toxicity, as it readily complexes with essential metal ions in biological systems.

Alkylation and Synthesis

Due to its nucleophilic nature, the cyano group can be readily introduced into organic molecules via alkylation reactions, displacing halide groups. This makes cyanide a valuable C1 synthon in organic synthesis for extending carbon chains and introducing functional groups.

Industrial Production

Andrussow Process

The primary industrial method for producing hydrogen cyanide is the Andrussow process. This involves reacting methane (CH₄) and ammonia (NH₃) in the presence of oxygen (O₂) over a platinum catalyst at high temperatures. Sodium cyanide, the precursor for many other cyanide compounds, is subsequently synthesized by neutralizing hydrogen cyanide with sodium hydroxide (NaOH).

The Peril of Cyanide

Mechanism of Action

Cyanide's extreme toxicity stems from its ability to inhibit the enzyme cytochrome c oxidase (Complex IV) in the mitochondrial electron transport chain. By binding to the iron center of this enzyme, cyanide disrupts cellular respiration, preventing the efficient aerobic production of ATP. This leads to histotoxic hypoxia, particularly affecting tissues with high energy demands like the central nervous system and heart.

Warning: Exposure can be rapidly fatal. Inhalation of gaseous HCN requires immediate respiratory protection.

Cellular Impact

The disruption of the electron transport chain halts aerobic metabolism. Cells become unable to utilize oxygen for energy production, leading to a rapid depletion of cellular energy reserves. This cascade effect causes widespread cellular dysfunction and death, manifesting as severe systemic poisoning.

Exposure Routes and Lethality

Lethal exposure can occur through inhalation of HCN gas, or ingestion of soluble cyanide salts like NaCN or KCN. Ingestion of as little as 200 mg of solid cyanide or exposure to airborne concentrations of 270 ppm can be fatal within minutes. While organic nitriles generally have low toxicity, cyanohydrins can release HCN and pose a risk.

Industrial and Niche Uses

Mining Operations

Cyanide plays a crucial role in the extraction of precious metals, particularly gold and silver. In the cyanide process, it selectively dissolves these metals from ores by forming soluble complexes like [Au(CN)₂]⁻ and [Ag(CN)₂]⁻. While effective, this process carries significant environmental risks if not managed properly, including potential contamination of waterways.

Chemical Synthesis

Beyond mining, cyanides are vital intermediates in industrial organic chemistry, primarily for synthesizing nitriles. These nitriles serve as precursors for various products, including pharmaceuticals, dyes, and polymers. Compounds like cyanogen chloride and cyanuric chloride are also derived from cyanide.

Pest Control and Other Uses

Cyanide compounds are employed in pest control, notably in devices used to manage populations of coyotes and invasive species like possums in New Zealand. They have also been used historically for fumigating ships and controlling ants. Niche applications include use in jewelry finishing (potassium ferrocyanide) and certain photographic processes.

Food Additives

Certain cyanide derivatives, specifically ferrocyanides (e.g., sodium ferrocyanide, E535), are utilized in the food industry. Due to their high stability and inability to decompose into toxic levels within the body, they function effectively as anticaking agents in table salt.

Detection and Analysis

Quantitative Methods

Cyanide levels are typically quantified using analytical techniques such as potentiometric titration or titration with silver ions. Methods often involve purging cyanide from an acidified solution into a basic absorber, followed by analysis.

Qualitative Tests

Qualitative detection methods rely on characteristic color reactions. The formation of Prussian blue upon reaction with iron(II) sulfate in a cyanide solution is a classic qualitative test. Another method involves reacting cyanide with p-benzoquinone in DMSO, producing a fluorescent product detectable under UV light.

Safe Disposal Practices

Regulatory Compliance

Due to its high toxicity, the disposal of cyanide waste is strictly regulated. Common industrial treatment methods focus on destroying cyanide, primarily through oxidation using agents like hydrogen peroxide, sulfur dioxide with copper salts (Inco process), or peroxysulfuric acid. High-temperature hydrolysis is also effective but requires specialized equipment. Acidification for HCN recovery is another option.

Cyanide Antidotes

Modern and Traditional Treatments

Hydroxocobalamin (Cyanokit) is a modern antidote that binds directly with cyanide to form cyanocobalamin (Vitamin B12), which is safely excreted. An older antidote regimen involves nitrites (amyl nitrite, sodium nitrite) to oxidize hemoglobin to methemoglobin, which competes with cytochrome oxidase for cyanide. Sodium thiosulfate is administered concurrently to provide sulfur for the enzyme rhodanese, facilitating the conversion of cyanide to the less toxic thiocyanate for renal excretion.

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References

IUPAC Gold Book nitriles

NCBI-MeSH Nitriles

Botz Michael M. Overview of cyanide treatment methods. Elbow Creek Engineering, Inc. http://www.botz.com/MEMCyanideTreatment.pdf

Cyanide Toxicity~treatment at eMedicine

Dzombak, David A; Ghosh, Rajat S; Wong-Chong, George M. Cyanide in Water and Soil. CRC Press, 2006, Chapter 11.2: "Use of Cyanide for Capturing Live Reef Fish".

A full list of references for this article are available at the Cyanide Wikipedia page

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Advisory Notice

This content has been generated by an AI model for educational and informational purposes only. It is based on data from Wikipedia and may not be exhaustive, fully accurate, or entirely up-to-date.

This is not professional chemical, safety, or medical advice. The information provided herein should not substitute for consultation with qualified chemists, safety professionals, or healthcare providers. Always refer to official safety data sheets, regulatory guidelines, and expert consultation for handling, safety protocols, and medical treatment related to cyanide.

The creators of this page assume no liability for any errors, omissions, or actions taken based on the information presented.

Cyanide: The Molecule of Paradox

💡 Dive in with Flashcard Learning! 💡

Cyanide: Fundamental Concepts ℹ️

🔗 Chemical Identity

🌿 Natural Occurrence

🔥 Combustion Product

The Cyanide Bond ⚛️

🔬 Molecular Structure

Cyanide's Presence 🌍

🌱 Biological Origins

🌌 Interstellar Medium

💨 Combustion Byproduct

Organic Cyanide Derivatives ⚗️

🧪 Nitriles and Cyanohydrins

Chemical Reactivity 🔄

💧 Hydrolysis and Protonation

⚡ Redox and Complexation

➕ Alkylation and Synthesis

Industrial Production 🏭

🔥 Andrussow Process

The Peril of Cyanide ☠️

🛑 Mechanism of Action

⚡ Cellular Impact

⚠️ Exposure Routes and Lethality

Industrial and Niche Uses 💡

⛏️ Mining Operations

⚙️ Chemical Synthesis

🛡️ Pest Control and Other Uses

🍽️ Food Additives

Detection and Analysis 🔍

📊 Quantitative Methods

🔵 Qualitative Tests

Safe Disposal Practices ♻️

📜 Regulatory Compliance

Cyanide Antidotes ⛑️

💊 Modern and Traditional Treatments

Teacher's Corner 🧑‍🏫

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Dive in with Flashcard Learning!

Cyanide: Fundamental Concepts

Chemical Identity

Natural Occurrence

Combustion Product

The Cyanide Bond

Molecular Structure

Cyanide's Presence

Biological Origins

Interstellar Medium

Combustion Byproduct

Organic Cyanide Derivatives

Nitriles and Cyanohydrins

Chemical Reactivity

Hydrolysis and Protonation

Redox and Complexation

Alkylation and Synthesis

Industrial Production

Andrussow Process

The Peril of Cyanide

Mechanism of Action

Cellular Impact

Exposure Routes and Lethality

Industrial and Niche Uses

Mining Operations

Chemical Synthesis

Pest Control and Other Uses

Food Additives

Detection and Analysis

Quantitative Methods

Qualitative Tests

Safe Disposal Practices

Regulatory Compliance

Cyanide Antidotes

Modern and Traditional Treatments

Teacher's Corner

True or False?

Test Your Knowledge!

Gamer's Corner

Discover other topics to study!

References

Feedback & Support

Important Disclaimer

Advisory Notice