In organic chemistry, an alkane, or paraffin, is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon–carbon bonds are single. Alkanes have the general chemical formula CnH2n+2. The alkanes range in complexity from the simplest case of methane, where n = 1, to arbitrarily large and complex molecules, like pentacontane or 6-ethyl-2-methyl-5-(1-methylethyl) octane, an isomer of tetradecane.
In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest of the molecule's composition. This enables systematic prediction of chemical reactions and behavior of chemical compounds and the design of chemical synthesis. The reactivity of a functional group can be modified by other functional groups nearby. Functional group interconversion can be used in retrosynthetic analysis to plan organic synthesis.
A methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms — CH3. In formulas, the group is often abbreviated Me. Such hydrocarbon groups occur in many organic compounds. It is a very stable group in most molecules. While the methyl group is usually part of a larger molecule, it can be found on its own in any of three forms: anion, cation or radical. The anion has eight valence electrons, the radical seven and the cation six. All three forms are highly reactive and rarely observed.
In chemistry, aromaticity is a property of cyclic (ring-shaped), typically planar (flat) molecular structures with pi bonds in resonance that gives increased stability compared with other geometric or connective arrangements with the same set of atoms. Aromatic rings are very stable and do not break apart easily. Organic compounds that are not aromatic are classified as aliphatic compounds—they might be cyclic, but only aromatic rings have enhanced stability.
Cubane (C8H8) is a synthetic hydrocarbon molecule that consists of eight carbon atoms arranged at the corners of a cube, with one hydrogen atom attached to each carbon atom. A solid crystalline substance, cubane is one of the Platonic hydrocarbons and a member of the prismanes. It was first synthesized in 1964 by Philip Eaton and Thomas Cole. Before this work, researchers believed that cubic carbon-based molecules would be too unstable to exist. The cubic shape requires the carbon atoms to adopt an unusually sharp 90° bonding angle, which would be highly strained as compared to the 109.45° angle of a tetrahedral carbon. Once formed, cubane is quite kinetically stable, due to a lack of readily available decomposition paths. It is the simplest hydrocarbon with octahedral symmetry.
Cyclopropene is an organic compound with the formula C3H4. It is the simplest cycloalkene. Because the ring is highly strained, cyclopropene is difficult to prepare and highly reactive. This colorless gas has been the subject for many fundamental studies of bonding and reactivity. It does not occur naturally, but derivatives are known in some fatty acids. Derivatives of cyclopropene are used commercially to control ripening of some fruit.
Adamantane is an organic compound with a formula C10H16 or, more descriptively, (CH)4(CH2)6. Adamantane molecules can be described as the fusion of three cyclohexane rings. The molecule is both rigid and virtually stress-free. Adamantane is the most stable isomer of C10H16. The spatial arrangement of carbon atoms in the adamantane molecule is the same as in the diamond crystal. This similarity led to the name adamantane, which is derived from the Greek adamantinos (relating to steel or diamond). It is a white solid with a camphor-like odor. It is the simplest diamondoid.
In chemistry, orbital hybridisation is the concept of mixing atomic orbitals to form new hybrid orbitals suitable for the pairing of electrons to form chemical bonds in valence bond theory. For example, in a carbon atom which forms four single bonds the valence-shell s orbital combines with three valence-shell p orbitals to form four equivalent sp3 mixtures in a tetrahedral arrangement around the carbon to bond to four different atoms. Hybrid orbitals are useful in the explanation of molecular geometry and atomic bonding properties and are symmetrically disposed in space. Usually hybrid orbitals are formed by mixing atomic orbitals of comparable energies.
Dodecahedrane is a chemical compound, a hydrocarbon with formula C20H20, whose carbon atoms are arranged as the vertices (corners) of a regular dodecahedron. Each carbon is bound to three neighbouring carbon atoms and to a hydrogen atom. This compound is one of the three possible Platonic hydrocarbons, the other two being cubane and tetrahedrane.
In chemistry, the organic compound triphenylene is a flat polycyclic aromatic hydrocarbon (PAH) consisting of four fused benzene rings. Triphenylene can be isolated from coal tar. It is also made synthetically by synthesis and trimerization of benzyne. One molecule of triphenylene has delocalized 18-π-electron systems based on a planar structure. It has the molecular formula C
18H
12.
Neopentane, also called 2,2-dimethylpropane, is a double-branched-chain alkane with five carbon atoms. Neopentane is a flammable gas at room temperature and pressure which can condense into a highly volatile liquid on a cold day, in an ice bath, or when compressed to a higher pressure.
Prismane or 'Ladenburg benzene' is a polycyclic hydrocarbon with the formula C6H6. It is an isomer of benzene, specifically a valence isomer. Prismane is far less stable than benzene. The carbon (and hydrogen) atoms of the prismane molecule are arranged in the shape of a six-atom triangular prism—this compound is the parent and simplest member of the prismanes class of molecules. Albert Ladenburg proposed this structure for the compound now known as benzene. The compound was not synthesized until 1973.
In a tetrahedral molecular geometry, a central atom is located at the center with four substituents that are located at the corners of a tetrahedron. The bond angles are cos−1(−1⁄3) = 109.4712206...° ≈ 109.5° when all four substituents are the same, as in methane as well as its heavier analogues. Methane and other perfectly symmetrical tetrahedral molecules belong to point group Td, but most tetrahedral molecules have lower symmetry. Tetrahedral molecules can be chiral.
Trimethylenemethane is a chemical compound with formula C
4H
6. It is a neutral free molecule with two unsatisfied valence bonds, and is therefore a highly reactive free radical. Formally, it can be viewed as an isobutylene molecule C
4H
8 with two hydrogen atoms removed from the terminal methyl groups.
Acepentalene is a tricyclic anti-aromatic compound. Its molecular formula is C10H6. It consists of three five-membered rings fused across three of the five carbon atoms. The central carbon atom in acepentalene is part of all three rings. There are formally five double bonds in acepentalene, so that the molecule formally contains four double bonds on the exterior, and one double bond from the central carbon to the exterior of the ring system.
[1.1.1]Propellane is an organic compound, the simplest member of the propellane family. It is a hydrocarbon with formula C5H6 or C2(CH2)3. The molecular structure consists of three rings of three carbon atoms each, sharing one C–C bond.
[2.2.2]Propellane, formally tricyclo[2.2.2.01,4]octane is an organic compound, a member of the propellane family. It is a hydrocarbon with formula C8H12, or C2(C2H4)3. Its molecule has three rings with four carbon atoms each, sharing one C–C bond.
Basketene (IUPAC name: pentacyclo[4.4.0.02,5.03,8.04,7]dec-9-ene) is an organic compound with the formula C10H10. It is a polycyclic alkene and the dehydrogenated version of basketane, which was named for its structural similarity to a basket. Due to its hydrocarbon composition and unique structure, the chemical compound is of considerable interest to those examining energy surfaces of these (CH)10 cage molecules and what possible factors influence their minima. Additionally, the complex structure of this compound has intrigued researchers studying the chemistry of highly strained ring systems. Basketene and its family of derivatives also have important chemical and physical properties. These molecules all tend to have a high standard enthalpy of formation, combined with their high density, leading to possible uses in explosives.
Calicene or triapentafulvalene is a hydrocarbon of the fulvalene class with chemical formula C8H6, composed of a cyclopentadiene ring and a cyclopropene ring linked by a double bond. Its name is derived from the Latin calix meaning "goblet", from its shape.
Cyclononatetraene is an organic compound with the formula C9H10. It was first prepared in 1969 by protonation of the corresponding aromatic anion (described below). It is unstable and isomerizes with a half-life of 50 minutes at room temperature to 3a,7a-dihydro-1H-indene via a thermal 6π disrotatory electrocyclic ring closing. Upon exposure to ultraviolet light, it undergoes a photochemical 8π electrocyclic ring closing to give bicyclo[6.1.0]nona-2,4,6-triene.
