Aromatic compounds are those chemical compounds that contain one or more rings with pi electrons delocalized all the way around them. In contrast to compounds that exhibit aromaticity, aliphatic compounds lack this delocalization. The term "aromatic" was assigned before the physical mechanism determining aromaticity was discovered, and referred simply to the fact that many such compounds have a sweet or pleasant odour; however, not all aromatic compounds have a sweet odour, and not all compounds with a sweet odour are aromatic. Aromatic hydrocarbons, or arenes, are aromatic organic compounds containing solely carbon and hydrogen atoms. The configuration of six carbon atoms in aromatic compounds is called a "benzene ring", after the simple aromatic compound benzene, or a phenyl group when part of a larger compound.
A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and plus (+) and minus (−) signs. These are limited to a single typographic line of symbols, which may include subscripts and superscripts. A chemical formula is not a chemical name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulae can fully specify the structure of only the simplest of molecules and chemical substances, and are generally more limited in power than chemical names and structural formulae.
A coordination complex consists of a central atom or ion, which is usually metallic and is called the coordination centre, and a surrounding array of bound molecules or ions, that are in turn known as ligands or complexing agents. Many metal-containing compounds, especially those of transition metals, are coordination complexes.
Cis–trans isomerism, also known as geometric isomerism or configurational isomerism, is a term used in organic chemistry. The prefixes "cis" and "trans" are from Latin: "this side of" and "the other side of", respectively. In the context of chemistry, cis indicates that the functional groups (substituents) are on the same side of some plane, while trans conveys that they are on opposing sides. Cis-trans isomers are stereoisomers, that is, pairs of molecules which have the same formula but whose functional groups are in different orientations in three-dimensional space. Cis-trans notation does not always correspond to E–Z isomerism, which is an absolute stereochemical description. In general, stereoisomers contain double bonds that do not rotate, or they may contain ring structures, where the rotation of bonds is restricted or prevented. Cis and trans isomers occur both in organic molecules and in inorganic coordination complexes. Cis and trans descriptors are not used for cases of conformational isomerism where the two geometric forms easily interconvert, such as most open-chain single-bonded structures; instead, the terms "syn" and "anti" are used.
Xylene (from Greek ξύλον xylon, "wood"), xylol or dimethylbenzene is any one of three isomers of dimethylbenzene, or a combination thereof. With the formula (CH3)2C6H4, in each of the three compounds a benzene ring is substituted by two methyl groups. They are all colorless, flammable, slightly greasy liquids. They are of great industrial value. The mixture is referred to as both xylene and, more precisely, xylenes. Mixed xylenes refers to a mixture of the xylenes plus ethylbenzene. The four compounds have identical empirical formulas C8H10. Typically the four compounds are produced together by various catalytic reforming and pyrolysis methods.
1,4-Cyclohexadiene is an organic compound with the formula C6H8. It is a colourless, flammable liquid that is of academic interest as a prototype of a large class of related compounds called terpenoids, an examples being γ-terpinene. An isomer exists of this compound, 1,3-cyclohexadiene.
Carboranes are electron-delocalized clusters composed of boron, carbon and hydrogen atoms that may also contain other metallic and nonmetallic elements in the cluster framework. Like many of the related boron hydrides, these clusters are polyhedra or fragments of polyhedra, and are similarly classified as closo-, nido-, arachno-, hypho-, etc., based on whether they represent a complete (closo-) polyhedron or a polyhedron that is missing one (nido-), two (arachno-), three (hypho-), or more vertices. Carboranes are a notable example of heteroboranes.
Trimethoxyamphetamines (TMAs) are a family of isomeric psychedelic hallucinogenic drugs. There exist six different TMAs that differ only in the position of the three methoxy groups: TMA, TMA-2, TMA-3, TMA-4, TMA-5, and TMA-6. The TMAs are analogs of the phenethylamine cactus alkaloid mescaline. The TMAs are substituted amphetamines, however, their action does not resemble that of the unsubstituted compound amphetamine, which is a stimulant and not a psychedelic. It is reported that some TMAs elicit a range of emotions ranging from sadness to empathy and euphoria. TMA was first synthesized by Hey, in 1947. Synthesis data as well as human activity data has been published in the book PiHKAL.
Cyanate is an anion with the structural formula [O=C=N]−, usually written OCN−. It also refers to any salt containing it, such as ammonium cyanate.
Xylyl bromide, also known as methylbenzyl bromide or T-stoff ("Substance-T"), is any member or a mixture of organic chemical compounds with the molecular formula C6H4(CH3)(CH2Br). The mixture was formerly used as a tear gas and has an odor reminiscent of lilac. All members and the mixture are colourless liquids, although commercial or older samples appear yellowish.
In chemistry, octahedral molecular geometry describes the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. The octahedron has eight faces, hence the prefix octa. The octahedron is one of the Platonic solids, although octahedral molecules typically have an atom in their centre and no bonds between the ligand atoms. A perfect octahedron belongs to the point group Oh. Examples of octahedral compounds are sulfur hexafluoride SF6 and molybdenum hexacarbonyl Mo(CO)6. The term "octahedral" is used somewhat loosely by chemists, focusing on the geometry of the bonds to the central atom and not considering differences among the ligands themselves. For example, [Co(NH
3)
6]3+, which is not octahedral in the mathematical sense due to the orientation of the N−H bonds, is referred to as octahedral.
Arene substitution patterns are part of organic chemistry IUPAC nomenclature and pinpoint the position of substituents other than hydrogen in relation to each other on an aromatic hydrocarbon.
2,6-Xylenol is a chemical compound which is one of the six isomers of xylenol. It is also commonly known as 2,6-dimethylphenol (DMP).
4,4′-Biphenol is an organic compound which is a phenolic derivative of biphenyl. It is a colorless solid.
Hexachlorocyclohexane (HCH), C
6H
6Cl
6, is any of several polyhalogenated organic compounds consisting of a six-carbon ring with one chlorine and one hydrogen attached to each carbon. This structure has nine stereoisomers, which differ by the stereochemistry of the individual chlorine substituents on the cyclohexane. It is sometimes erroneously called "benzene hexachloride" (BHC). They have been used as models for analyzing the effects of different geometric positions of the large atoms with dipolar bonds on the stability of the cyclohexane conformation. The isomers are poisonous, pesticidal, and persistent organic pollutants, to varying degrees.
In chemistry, isomers are molecules or polyatomic ions with identical molecular formulas — that is, same number of atoms of each element — but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers.
Cyclopentadienyliron dicarbonyl dimer is an organometallic compound with the formula [(η5-C5H5)Fe(CO)2]2, often abbreviated to Cp2Fe2(CO)4, [CpFe(CO)2]2 or even Fp2, with the colloquial name "fip dimer". It is a dark reddish-purple crystalline solid, which is readily soluble in moderately polar organic solvents such as chloroform and pyridine, but less soluble in carbon tetrachloride and carbon disulfide. Cp2Fe2(CO)4 is insoluble in but stable toward water. Cp2Fe2(CO)4 is reasonably stable to storage under air and serves as a convenient starting material for accessing other Fp (CpFe(CO)2) derivatives (described below).
Dinitrobenzenes are chemical compounds composed of a benzene ring and two nitro group (-NO2) substituents. The three possible arrangements of the nitro groups afford three isomers, 1,2-dinitrobenzene, 1,3-dinitrobenzene, and 1,4-dinitrobenzene. Each isomer has the chemical formula C6H4N2O4 and a molar mass of about 168.11 g/mol. 1,3-Dinitrobenzene is the most common isomer and it is used in the manufacture of explosives.
Thienothiophene usually refers to any of three structurally related derivatives of thiophene with the formula C6H4S2. In order of importance, they are: thieno(3,2-b)thiophene, thieno(2,3-b)thiophene, and thieno(3,4-b)thiophene. Other isomers feature S(IV) and are less stable. Thieno[2,3-b]thiophene was the first member of the series to be isolated. It was obtained in very low yield upon heating citric acid, a source of a six-carbon linear chain, with P4S10. More efficient syntheses of this and the other two stable thienothiophenes involve cyclization reactions of substituted thiophenes.
2,2′-Biphenol is an organic compound with the formula (C6H4OH)2. It is one of three symmetrical isomers of biphenol. A white solid, it is a precursor to diphosphite ligands that are used to support industrial hydroformylation catalysis.