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Terms and Definitions
Published in Rick Houghton, William Bennett, Emergency Characterization of Unknown Materials, 2020
Rick Houghton, William Bennett
Organic covalent bonds contain energy for reactions. Single carbon-carbon bonds are the most stable. If the carbons are linked somewhere with a double carbon bond, it means there are not as many places for hydrogen to fit. The presence of a carbon = carbon double bond means the carbon chain is no longer saturated with hydrogen, so it is termed an unsaturated hydrocarbon. If someone refers to an unsaturated hydrocarbon, you can assume the molecule contains at least one carbon = carbon bond, which is more reactive than a carbon-carbon bond. Triple bonds are likely to produce a more violent reaction than a double bond.
Organic Chemistry Nomenclature
Published in Arthur W. Hounslow, Water Quality Data, 2018
Multiple bonds are the result of sharing more than one pair of electrons between two atoms. Double bonds are the sharing of two pairs of electrons and triple bonds are the sharing of three pairs of electrons. The hydrocarbons containing multiple bonds are called unsaturated compounds, whereas those with only single bonds are called saturated compounds. In multiple-bond compounds one pair of electrons is found between the two atoms, but the other pair or two pairs of electrons are found perpendicular to this axis in lobes extending above and below the axis. This sideward overlap prevents rotation around the two-atom axis.
Indoor Air Pollution
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
The classifications for hydrocarbons, defined by the IUPAC nomenclature of organic chemistry, are as follows: methane, ethane, propane, butane, pentane, hexane, heptanes, octane, etc. Saturated hydrocarbons are the basis of petroleum fuels and are found as either linear or branched species. Natural gas (methane) is the number 1 inducer and propagator of chemical sensitivity, along with pesticides. Saturated hydrocarbons (alkanes are the simplest of the hydrocarbon species and are composed entirely of single bonds and are saturated with hydrogen. The general formula for saturated hydrocarbons is CnH2n+2 [assuming noncyclic structures]).34 Hydrocarbons with the same molecular formula but different structural formulae are called structural isomers.35 As given in the example of 3-methylhexane and its higher homologs, branched hydrocarbons can be chiral.36 Chiral saturated hydrocarbons constitute the side chains of biomolecules such as chlorophyll and tocopherol.37Unsaturated hydrocarbons have one or more double or triple bonds between carbon atoms. Those with double bond are called alkenes. Those with one double bond have the formula CnH2n (assuming noncyclic structures).38 Those containing triple bonds are called alkynes, with general formula CnH2n−2 (Table 3.2).39
An inverse Ruddlesden-Popper nitride Ca7(Li1−xFex)Te2N2 grown from Ca flux
Published in Philosophical Magazine Letters, 2018
Gang Wang, S. Manni, Qisheng Lin, Patrick McVey, Robert S. Houk, Liming Wu, Sergey L. Bud’ko, Paul C. Canfield
Compared with their oxide counterparts, the growth and study of complex nitrides are difficult. Elemental nitrogen usually forms the diatomic molecule N2 which has a strong covalent triple bond. The transition from atomic N to a N−3 anion needs to overcome a high energy barrier. Many of the nitrides are metastable phases and easily decompose. On one hand, these issues contribute to the challenge of synthesising nitride materials. On the other hand, this situation offers a vast unexplored territory and creates excellent opportunities to discover new nitride materials with interesting crystal structures and properties by developing suitable synthetic methods to overcome these obstacles.
A TDDFT study of some dinuclear compounds containing CpM(CO)3 or CpM(CO)2 groups
Published in Molecular Physics, 2020
Another sort of compound is Cp2M2(CO)4 where M=Cr, Mo, W. They have C2h symmetry. Each M is bonded to a Cp ligand and two carbonyls. The Cp are in a trans position respect to the M≡M bond, and so are the couples of carbonyls. The M≡M bond is considered as a triple bond, with a theoretical bond order of 3.