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Methylene (IUPAC name: methylidene), with the chemical formula CH₂, is an organic compound classified as the simplest carbene, consisting of a neutral divalent carbon atom bonded to two hydrogen atoms and bearing two non-bonding valence electrons.^[1]^[2] As a transient, highly reactive species, methylene exists primarily in the gas phase and is unstable under standard conditions, persisting only in dilute matrices or at low temperatures, where it appears as a colorless gas that fluoresces in the mid-infrared spectrum.^[1]^[3] Its molecular weight is 14.027 g/mol, and it exhibits two electronic states: the ground-state triplet methylene (³CH₂), with two unpaired electrons and a bent geometry (bond angle approximately 136°), and the excited singlet methylene (¹CH₂), with paired electrons and a more acute bond angle (around 102°), the latter being about 9 kcal/mol higher in energy.^[1]^[2] Methylene is generated in laboratories through methods such as the photolysis or thermolysis of diazomethane (CH₂N₂), α-elimination from dihalomethanes, or pyrolysis of ketene.^[2] In organic synthesis, it plays a crucial role as a reactive intermediate, facilitating reactions like stereospecific cyclopropanation of alkenes (via singlet state, proceeding concertedly) and diradical additions (via triplet state, often stepwise), as well as C–H insertions and ylide formations, enabling the construction of strained rings and complex carbon skeletons.^[2] The study of methylene's singlet-triplet interconversion and reactivity has been foundational in carbene chemistry since the mid-20th century, with landmark experiments by Skell and Woodworth in 1956 demonstrating its stereospecificity using cis- and trans-2-butene.^[2] Beyond synthesis, methylene contributes to atmospheric chemistry, combustion processes, and astrochemistry, where it participates in radical chain reactions and interstellar molecule formation.^[4]

Nomenclature and History

Nomenclature

The reactive intermediate with the formula :CH₂ is systematically named methylidene according to IUPAC recommendations, where it serves as the parent hydride for carbene nomenclature.^[5] It is also referred to as methylene in common usage or simply as carbene when denoting the class of divalent carbon species.^[1] The term "methylene" originated in 1835, coined by French chemists Jean-Baptiste Dumas and Eugène-Melchior Péligot during their studies on methanol (wood alcohol), derived from the Greek words methy (wine) and hylē (wood) to reflect its source from wood distillation.^[6] This nomenclature must be distinguished from the methylene group (-CH₂-), which represents a bivalent radical in saturated hydrocarbon chains such as in ethane (CH₃-CH₂-CH₃), and the methylidene group (=CH₂), which denotes a doubly bonded unit in unsaturated compounds like in propene (CH₃-CH=CH₂).^[7] The notation :CH₂ specifically highlights the carbene's divalent carbon atom, featuring a lone pair or unpaired electrons in its electronic configuration.^[5]

Historical Development

The earliest attempts to isolate methylene (CH₂) date back to 1835, when Jean-Baptiste-André Dumas and Eugène-Melchior Péligot isolated methanol from wood spirit and sought to generate the free CH₂ species by dehydration of methanol, viewing it as a hydrate of methylene.^[8] This work introduced the term "methylene" (from Greek roots meaning "wood wine") to describe the hypothetical CH₂ unit, though they failed to isolate the elusive species, and the reactive nature of CH₂ remained unrecognized.^[8] Over the subsequent century, fleeting reactive intermediates in various reactions were occasionally attributed to CH₂, but it was widely misconstrued as a stable radical or biradical species rather than a distinct class of divalent carbon intermediate.^[8] The modern understanding of methylene as a carbene began in the early 1950s with the pioneering work of William von E. Doering, who generated CH₂ via photolysis of diazomethane (CH₂N₂) and demonstrated its insertion into C-H bonds and addition to alkenes to form cyclopropanes, thereby establishing carbene chemistry as a field. Doering's experiments, conducted in 1954, provided the first concrete evidence of CH₂'s transient reactivity and laid the groundwork for systematic studies of carbene generation and reactions in the 1960s, influencing subsequent researchers like Robert Breslow and Maitland Jones Jr.^[8] These developments shifted the perception of CH₂ from an elusive radical to a well-defined reactive intermediate with unique electronic properties. A pivotal confirmation came in 1959 from Gerhard Herzberg's spectroscopic studies using flash photolysis of diazomethane, which captured the vacuum ultraviolet absorption spectrum of CH₂ and established its bent triplet ground state (³B₁), definitively distinguishing it from monovalent radicals. Herzberg's Nobel Prize-winning techniques not only verified CH₂'s existence but also resolved debates about its multiplicity, paving the way for deeper insights into its singlet-triplet interconversion and role in organic synthesis. By the mid-1960s, this body of work had fully transformed CH₂ from a misunderstood entity into a cornerstone of carbene reactivity, enabling precise control in laboratory applications.^[8]

Physical and Structural Properties

Molecular Structure

The methylene molecule (CH₂) adopts bent equilibrium geometries in both its singlet (¹A₁) and triplet (³B₁) states, reflecting the influence of its electronic configuration on bonding. In the triplet ground state, the H-C-H bond angle is 133.84° with C-H bond lengths of 1.075 Å, as determined from high-resolution spectroscopic analysis combined with theoretical fitting of the potential energy surface.^[9] The carbon atom in this state exhibits diradical character, with the two unpaired electrons occupying nearly degenerate non-bonding orbitals (one σ-like and one π-like), consistent with an sp² hybridization, with the two unpaired electrons occupying one in-plane σ orbital and one perpendicular p orbital.^[10] In contrast, the singlet excited state features a narrower H-C-H bond angle of approximately 102° and longer C-H bond lengths of 1.107 Å, derived from experimental rotational constants and ab initio computations at the coupled-cluster level. Here, the carbon is also sp² hybridized, but the lone pair occupies the in-plane σ orbital, while the empty p orbital lies orthogonal to the plane, leading to greater bending due to repulsion between the lone pair and the C-H bonding pairs. These state-specific geometries arise from the variation in molecular orbital energies with bond angle, as illustrated by Walsh diagrams for AH₂ systems, where the bending stabilizes the occupied orbitals differently for singlet and triplet configurations. Equilibrium structures for both states have been corroborated experimentally through infrared and microwave spectroscopy, providing precise rotational and vibrational data for validation of computational predictions.^[9]

Spectroscopic Properties

The ultraviolet absorption spectrum of CH₂ reveals a prominent band at 141.5 nm, attributed to the transition from the ground triplet state (X³B₁) to an excited triplet state, providing key evidence for its electronic structure despite the molecule's short-lived nature in the gas phase. This vacuum ultraviolet feature, first observed through flash photolysis techniques, enables kinetic monitoring of triplet CH₂ and highlights the challenges in detecting the reactive species directly due to its broad, diffuse character.^[11] Infrared spectroscopy of CH₂, particularly through fluorescence and absorption in the mid-infrared region (approximately 1200–3000 cm⁻¹), captures the vibrational modes associated with C–H stretches and bends, offering insights into its bent geometry and bond strengths. For the triplet state, the symmetric and antisymmetric C–H stretching fundamentals appear at 3035 cm⁻¹ and 3249 cm⁻¹, respectively, while the bending mode (ν₂) appears around 963 cm⁻¹, with these emissions observed in low-temperature environments to mitigate rapid decay.^[12] Such spectra underscore the molecule's high reactivity, as vibrational relaxation occurs on microsecond timescales in the gas phase. Electron paramagnetic resonance (EPR) spectroscopy definitively confirms the triplet ground state of CH₂, exhibiting characteristic signals with a zero-field splitting parameter D ≈ 0.7 cm⁻¹, which reflects the unpaired electrons' spatial distribution and the molecule's non-linear structure. Early matrix-isolated EPR measurements at low temperatures yielded D values around 0.703 cm⁻¹, with temperature-dependent variations indicating partial rotation of the CH₂ moiety, further validating the spectroscopic assignment over theoretical predictions alone.^[13] Matrix isolation spectroscopy has been instrumental in stabilizing transient CH₂ within inert matrices like argon at cryogenic temperatures (typically 4–20 K), allowing detailed observation of its UV, IR, and EPR signatures without interference from reactive quenching. This technique isolates individual CH₂ units, revealing site-specific splittings in vibrational bands and enabling high-resolution studies that align gas-phase data with theoretical models of its electronic and vibrational states.^[14]

Electronic States and Reactivity

Singlet and Triplet States

The ground state of methylene (CH₂) is the triplet state, denoted as ³B₁, in which the two nonbonding electrons occupy orthogonal p-orbitals on the carbon atom as unpaired electrons with parallel spins.^[15] This configuration results in a diradical character and a bent geometry with a bond angle of approximately 136°.^[15] The lowest-energy singlet state, ¹A₁, lies approximately 9 kcal/mol above the triplet ground state and features a closed-shell electronic configuration where the nonbonding electrons are paired in a hybrid orbital.^[15] This state exhibits a more acute bond angle of about 102° compared to the triplet.^[15] The ¹A₁ state is readily populated via photolysis of precursors such as diazomethane or ketene at wavelengths around 300–400 nm.^[16] Spin-orbit coupling between the singlet and triplet states enables intersystem crossing, with effective rate constants on the order of 10⁸ s⁻¹ under typical experimental conditions. Theoretical studies of the potential energy surfaces for CH₂ demonstrate that the singlet and triplet states intersect along certain coordinates, such as the bending mode, providing barrierless pathways for nonadiabatic interconversion at minimum energy crossing points.^[15]

Radical Character and General Reactivity

Methylene (CH₂) possesses inherent diradical character stemming from its two non-bonding electrons, which occupy orthogonal orbitals in the triplet ground state, enabling radical-like reactivity. In the triplet state, CH₂ acts as a diradical species, preferentially undergoing stepwise hydrogen abstraction from substrates such as alkanes to form methyl radicals and alkyl radicals. Conversely, the excited singlet state facilitates concerted mechanisms, including direct insertion into bonds or cycloaddition reactions, reflecting closed-shell behavior.^[17] This state-dependent reactivity underscores the diradical nature of CH₂, where intersystem crossing between singlet and triplet states can modulate reaction pathways, though triplet CH₂ dominates under typical generation conditions. The divalent carbon center imparts exceptional electrophilicity and high reactivity, resulting in gas-phase lifetimes shorter than 1 μs in the presence of common quenchers, limiting observation to specialized techniques like matrix isolation or flash photolysis.^[18] Triplet CH₂ exhibits moderate selectivity in hydrogen abstraction, with rate constants for alkanes on the order of 10^{10}–10^{11} L mol⁻¹ s⁻¹ at 300 K, approaching the diffusion limit for primary C–H bonds but showing discrimination for tertiary sites.^[19] As the simplest carbene, CH₂ serves as the prototypical example in carbene chemistry, providing foundational insights into the electronic structure and reaction patterns of substituted carbenes.^[20]

Preparation Methods

Photochemical Generation

Photolysis of diazomethane (CH₂N₂) represents a cornerstone method for generating singlet methylene (:¹CH₂) under controlled laboratory conditions. Irradiation at 435 nm, corresponding to a strong absorption band of the precursor, leads to the efficient extrusion of nitrogen gas, producing :¹CH₂ + N₂ with a quantum yield approaching 1. This wavelength selectively excites the S₁ state of diazomethane, facilitating rapid dissociation on a femtosecond timescale to yield the reactive singlet carbene. The process is widely employed due to its high efficiency and the clean separation of inert N₂ byproduct. An alternative photochemical route involves the photolysis of ketene (H₂C=C=O) at 214 nm, which predominantly generates triplet methylene (³CH₂). Excitation in the vacuum ultraviolet region dissociates ketene into :³CH₂ + CO, with the triplet state arising from the spin-forbidden pathway favored at this shorter wavelength; the quantum yield for ³CH₂ formation is near unity under these conditions. This method is particularly useful for studying the distinct reactivity of the triplet carbene, which exhibits diradical character compared to the electrophilic singlet.^[11] Flash photolysis techniques have been instrumental in advancing kinetic studies of methylene, allowing precise control over the electronic state through wavelength selection. In these setups, high-intensity pulsed lamps or lasers deliver the appropriate irradiation (e.g., 435 nm for singlet or 214 nm for triplet generation), enabling time-resolved observation of :CH₂ lifetimes and reactions on microsecond timescales. Seminal experiments using flash photolysis of diazomethane and ketene have quantified intersystem crossing rates and deactivation pathways, providing foundational data on state-specific behavior.^[11] Due to the explosive nature of diazomethane and potential instability of ketene, photochemical generation requires stringent safety protocols, including preparation and handling under inert atmospheres such as argon or nitrogen to prevent detonation or unwanted side reactions. Generated :CH₂ is often monitored spectroscopically in real-time to confirm production and state purity.

Thermal Decomposition Routes

Thermal decomposition routes for generating methylene (CH₂) involve high-temperature pyrolysis of suitable precursors, providing an alternative to milder photochemical methods by leveraging heat to drive bond breaking and carbene extrusion. Early investigations into such processes laid the foundation for understanding radical and carbene formation in gas-phase reactions. In 1929, Paneth and Hofeditz pioneered the thermal generation of free alkyl radicals through the decomposition of mercury dialkyl compounds, such as dimethylmercury, at elevated temperatures around 500–600°C, demonstrating the transient nature of these species via mirror removal techniques in flow systems. This work established key techniques for studying reactive intermediates but pertains to methyl radicals (CH₃•), not methylene.^[21] A classic thermal route for singlet methylene involves the pyrolysis of diazomethane (CH₂N₂) at temperatures of 400–500°C, yielding :¹CH₂ + N₂ via unimolecular decomposition. This method produces vibrationally excited singlet carbene, which can be intercepted before intersystem crossing to the triplet state, and is widely used in gas-phase studies due to its selectivity.^[2] High-temperature pyrolysis of methanol (CH₃OH) at temperatures exceeding 1000 K represents another route, where decomposition primarily occurs via radical pathways, yielding CH₂ as an intermediate amid competing products such as hydrogen, methane, and carbon monoxide.^[22] This process is prominent in combustion environments, with onset around 910 K and complete conversion by 1150 K, though CH₂ forms transiently and requires rapid quenching for isolation. Shock tube experiments facilitate precise study of such high-temperature generations, simulating extreme conditions (1900–2800 K) and revealing activation energies around 80 kcal/mol for associated decomposition steps. Thermally produced CH₂ from these routes exhibits high reactivity, often inserting into C–H bonds or adding to unsaturated systems before dimerizing to ethylene.

Chemical Reactions

Reactions with Organic Substrates

Methylene (CH₂) in its singlet state undergoes stereospecific [2+1] cycloaddition reactions with alkenes, forming cyclopropanes as the primary products. This reaction proceeds via a concerted mechanism, preserving the stereochemistry of the alkene substrate. For instance, the addition of singlet CH₂ to ethylene yields cyclopropane, a process first demonstrated through the photolysis of diazomethane in the presence of ethylene. The reaction is highly efficient and occurs at near-collision rates, with rate constants for singlet CH₂ addition to simple olefins typically ranging from 10⁸ to 10⁹ L mol⁻¹ s⁻¹ at room temperature, reflecting the electrophilic nature of the carbene and the nucleophilic π-bond of the alkene. In contrast to the triplet state, which leads to non-stereospecific addition and hydrogen abstraction, the singlet pathway is particularly useful in synthesis for constructing strained rings with defined stereochemistry. Substituted alkenes, such as cis- or trans-2-butene, produce the corresponding cis- and trans-1,2-dimethylcyclopropanes, respectively, without isomerization. This stereospecificity arises from the synchronous overlap of the carbene's empty p-orbital with the alkene's π-system, forming a three-membered ring in a suprafacial manner. The synthetic utility of this transformation has been exploited in the preparation of complex natural products, where cyclopropane moieties serve as versatile intermediates for ring expansion or opening. Singlet CH₂ also inserts into C-H bonds of alkanes, generating new C-C bonds and forming higher homologues. A prototypical example is the insertion into methane to produce ethane (CH₂ + CH₄ → C₂H₆), observed in gas-phase photolysis experiments. This reaction exhibits little to no selectivity, showing relative rates close to statistical (per hydrogen basis) for primary, secondary, and tertiary C-H bonds in alkanes like propane and isobutane. Absolute rate constants for these insertions are on the order of 10⁰ to 10¹ L mol⁻¹ s⁻¹, significantly slower than additions to alkenes, indicating a higher activation barrier due to the non-polar σ-bond. The process is thought to involve a concerted, four-center transition state, though abstraction-recombination pathways may contribute under certain conditions. With carbonyl compounds, singlet CH₂ reacts to form carbonyl ylides, which are 1,3-dipoles capable of further transformations. For example, the addition to a ketone such as acetone generates an ylide intermediate that can cyclize to an epoxide or undergo 1,2-migration to yield a homologated carbonyl compound, for example, with acetone to yield butan-2-one via 1,2-methyl migration in the ylide intermediate. This ylide formation is reversible and competes with direct O-H insertion, with the outcome depending on the substrate's substitution and reaction conditions. The reaction's versatility has made it a cornerstone for carbon homologation in organic synthesis, particularly in the construction of oxygenated frameworks.

Reactions with Inorganic Compounds

Methylene, particularly in its triplet ground state (^3CH_2), exhibits radical-like reactivity with various inorganic molecules, often involving abstraction or addition pathways that lead to oxygenated or other functionalized products. These reactions are significant in combustion chemistry and atmospheric processes, where methylene acts as a reactive intermediate. Singlet methylene (^1CH_2), being more electrophilic, can participate in concerted insertions, though such pathways are less common with simple inorganic diatomics due to energy barriers.^[23] The reaction of triplet methylene with dioxygen is a key example, proceeding via initial addition to form a peroxyl diradical intermediate, followed by fragmentation. This yields molecular hydrogen, carbon monoxide, and carbon dioxide as major products, with quantum yields indicating efficient conversion under gas-phase conditions. The overall process is exothermic and plays a role in the oxidation of hydrocarbons.^[23] With dihydrogen, triplet methylene undergoes hydrogen atom abstraction to produce methyl radical and atomic hydrogen: ^3CH_2 + H_2 → CH_3 + H. This pathway has a low activation barrier of approximately 10 kcal/mol and is stereospecific in isotopic labeling studies, highlighting the diradical character of the intermediate. Singlet methylene, in contrast, can insert into the H-H bond to form ethane directly, though this requires higher energy input.^[24] Triplet methylene reacts with carbon dioxide primarily through oxygen atom abstraction, yielding formaldehyde and carbon monoxide: ^3CH_2 + CO_2 → H_2CO + CO. Kinetic studies report a bimolecular rate constant of about 1.5 × 10^{-13} cm^3 molecule^{-1} s^{-1} at room temperature, with the reaction being endothermic by roughly 8 kcal/mol but facilitated in high-temperature environments like flames. Alternative addition-fragmentation routes via a carbonyl ylide intermediate are possible but higher in energy.^[25] The interaction of singlet methylene with dinitrogen is theoretically proposed to form diazomethane via a barrierless addition, though experimental evidence is limited due to the high endothermicity (about 50 kcal/mol) and competition with other decay channels. In specialized contexts, such as Titan's atmosphere simulations, this pathway could contribute to cyanoacetylene formation, but it remains minor under Earth conditions. Triplet methylene shows negligible reactivity with N_2.^[26]

References

[1]
Methylene | CH2 | CID 123164 - PubChem - NIH
Methylene | CH2 | CID 123164 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, ...
[2]
Carbenes - Chemistry LibreTexts
Jan 22, 2023 · A carbene is a molecule containing a neutral carbon atom with a valence of two and two unshared valence electrons.
[3]
Methylene
### Summary of Methylene (CH₂) Properties
[4]
STRUCTURE OF CARBENE, CH2 - ACS Publications
The beginnings of modern carbene chemistry triplets and singlets. ... Geometry and singlet-triplet energy gap in methylene: a critical review of experimental and ...
[5]
carbenes (C00806) - IUPAC
The electrically neutral species H A 2 C : (methylene) and its derivatives, in which the carbon is covalently bonded to two univalent groups of any kind or ...
[6]
Eugène Melchior Peligot - ScienceDirect.com
Dumas and Peligot introduced the word methylene to organic chemistry (from the Greek methy = wine and ĥylê = wood). The existence of two alcohols led to the ...
[7]
Bring the power of IUPAC naming to your desktop! - ACD/Labs
The name methylene is used instead of methanediyl; the name methylidene is used for the group when doubly bonded to another part of the structure.
[8]
Carbenes Introduction | Chemical Reviews - ACS Publications
Jul 30, 2009 · A history is given of the quest for stable carbenes. It begins in 1835 with the attempts by Dumas to dehydrate MetOH to produce methylene.
[9]
A refined potential surface for the X̃ 3 B 1 electronic state of ...
Aug 1, 1983 · A refined potential surface for the X̃ 3B1 electronic state of methylene CH2 Available ... bond angle is 133.84°±0.05°, the height of the barrier ...
[10]
Ab initio post-HF CCSD(T) Calculations for Triplet and Singlet ...
The CH bond lengths of molecular states 1 to 4 were optimised via gradient methods at the CCSD(T) level in the frozen-core approximation for each of the four ...Results And Discussion · Equilibrium Ch Bond Lengths · Hch Valence Angles<|control11|><|separator|>
[11]
Flash Photolysis of Ketene and Diazomethane: The Production and ...
May 15, 1970 · Triplet methylene was monitored by kinetic spectroscopy at 141.5 nm. ... triplet absorption as a function of inert‐gas pressure indicates ...
[12]
EPR of methylene. Temperature dependence in a xenon matrix
Jun 15, 1977 · The EPR spectra of CH2 and CD2 were examined between 2.18 and 9.2 °K in a xenon matrix. The zero‐field splitting and linewidths of the ...
[13]
Electron paramagnetic resonance of CD2 and CHD. Isotope effects ...
The Spectrum, Structure and Singlet-Triplet Splitting in Methylene CH2. 1985 ... EPR of methylene. Temperature dependence in a xenon matrix. The ...
[14]
The X̃ 3B1, ã 1A1, b̃ 1B1, and c̃ 1A1 Electronic States of CH2
### Summary of Singlet and Triplet States of CH2
[15]
Flash Photolysis of Ketene and Diazomethane
May 15, 1970 · Methylene and methyl radicals were monitored by means of their absorptions at 141.5 and 150.4 nm, respectively. For CH2 and CHa, these bands are ...<|control11|><|separator|>
[16]
Low-Temperature Hydrogenation of Triplet Carbenes and Diradicaloid BiscarbenesElectronic State Selectivity
### Summary of Singlet and Triplet Methylene Reactivity
[17]
Rate constants for triplet methylene (~X3B1) removal by oxygen ...
Rate constants for triplet methylene (~X3B1) removal by oxygen, nitric oxide and acetylene from infrared diode laser flash kinetic spectroscopy. Click to copy ...
[18]
[PDF] Chemical Kinetic Data Base for Combustion Chemistry. Part I ...
Oct 15, 2009 · CH2, and triplet CH2• All possible reactions are considered. In ... The k/k~ values as a function of pressure and temperature are given ...
[19]
Quantum-Centric Computational Study of Methylene Singlet and ...
May 13, 2025 · This study involves quantum simulations of the dissociation of the ground-state triplet and first excited singlet states of the CH 2 molecule (methylene)
[20]
The Rise and Fall of Tetraethyllead. 1. Discovery and Slow ...
Paneth's explanation of his results in terms of the formation of free methyl radicals in the gas-phase thermal decomposition of tetramethyllead was questioned ...
[21]
Kinetics of the Thermal Decomposition of Dimethylmercury. I ...
The decomposition in excess cyclopentane is first order, with methane the major product (accounting for >95% of the carbon). Rate constants are dependent upon ...Missing: generate | Show results with:generate
[22]
[PDF] Kinetics of the Thermal Decomposition of Dimethylmercury. II ...
Kinetics of the Thermal Decomposition of Dimethylmercury. II. Carbon-13 ... C*H4+C*Hs+CH2+Hg ks/2. /'. C *Hs+ CHsHgC *Hs. '" C*H4+CHs+C*H2+Hg ks/2. C*Hs+ ...
[23]
Investigation and improvement of the kinetic mechanism for ...
An improved kinetic mechanism of methanol pyrolysis was proposed. · The intrinsic kinetic parameter of methanol decomposition was calculated. · The reaction path ...
[24]
https://pubs.acs.org/doi/10.1021/ja00816a008
[25]
Reactions of triplet methylene with oxygen. Formation of molecular ...
Insertion of methylene into the carbon-hydrogen bonds of the C1 to C4 alkanes. ... reaction rate constants on the basis of the summary values of the rate ...
[26]
Reaction pathways for the triplet methylene abstraction CH2(3B1) + ...
May 1, 1974 · Reaction pathways for the triplet methylene abstraction CH2(3B1) + H2 . far. CH3 + H | Journal of the American Chemical Society.
[27]
Reaction between triplet methylene and CO 2 : rate constant ...
The rate constant for the abstraction by triplet CH2 from CH2N2 to produce CH3 was determined to be 1.0 × 10−12 cm3 molecule−1 s−1. Previous article in issue
[28]
Subsequent Reaction of CH2(1A) with N2 Molecule as a Potentially ...
The calculated data reveal that HCN and C 2 H 4 are efficiently produced from the subsequent reaction of 1 CH 2 with N 2 molecules in the atmosphere of Titan.