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Air Force Two is the air traffic control designated call sign held by any United States Air Force aircraft carrying the vice president of the United States, but not the president. [ 1 ] [ 2 ] The term is often associated with the Boeing C-32 , a modified 757 which is most commonly used as the vice president's transport.
Hexafluorobenzene stands somewhat aside in the perhalogenbenzenes. If a perhalogenated benzene ring were to remain planar, then geometric constraints would force adjacent halogens closer than their associated nonbonding radius. Consequently the benzene ring buckles, reducing p-orbital overlap and aromaticity to avoid the steric clash ...
The driving force for ring-opening and polymerization is strain relief. The reaction is believed to be a living polymerization due to the lack of competing reactions. Because the two benzene rings are in close proximity this cyclophane type also serves as guinea pig for photochemical dimerization reactions as illustrated by this example: [ 21 ]
Cyclobutane is a larger ring, but still has bent bonds. In this molecule, the carbon bond angles are 90° for the planar conformation and 88° for the puckered one. Unlike in cyclopropane, the C–C bond lengths actually increase rather than decrease; this is mainly due to 1,3-nonbonded steric repulsion.
In alkanes, optimum overlap of atomic orbitals is achieved at 109.5°. The most common cyclic compounds have five or six carbons in their ring. [6] Adolf von Baeyer received a Nobel Prize in 1905 for the discovery of the Baeyer strain theory, which was an explanation of the relative stabilities of cyclic molecules in 1885.
The Indonesian Air Force also has special VIP squadrons for the President, Vice President and government ministers. [ citation needed ] These are the 17th Air Squadron ( Indonesian : Skadron Udara 17 ) operating Avro RJ85 , Boeing 737-400 , Falcon 7X and 8X , and Lockheed L-100 fixed-wing aircraft; and the 45th Air Squadron ( Indonesian ...
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. [2]
The ubiquitous compound can be found in coal tar, tobacco smoke and many foods, especially grilled meats. The substance with the formula C 20 H 12 is one of the benzopyrenes, formed by a benzene ring fused to pyrene. Its diol epoxide metabolites, more commonly known as BPDE, react with and bind to DNA, resulting in mutations and eventually cancer.