Resonance dioxide

Sharma R D and Brau C A 1967 Near-resonant vibrational energy transfer in nitrogen carbon dioxide mixtures Phys. Rev. Lett. 19 1273-5... 

Carbon dioxide has a linear structure. The simple double-bonded formula, however, does not fully explain the structure since the measured carbon-oxygen bond lengths are equal but intermediate between those expected for a double and a triple bond. A more accurate representation is, therefore, obtained by considering carbon dioxide as a resonance hybrid of the three structures given below ... 

The structure of nitrogen dioxide contains an unpaired (odd) electron and the molecule is consequently paramagnetic. The odd electron is not localised on any atom and the structure can be best represented as a resonance hybrid of the structures ... 

Unlike nitrogen monoxide, nitrogen dioxide has properties more typical of an odd electron molecule. It is a coloured (brown), reactive gas which dimerises to the diamagnetic colourless gas dinitrogen tetroxide, N2O4. in which the odd electron is paired. The structure of dinitrogen tetroxide can be represented as a resonance hybrid of ... 

Laser Photochemistry. Photochemical appHcations of lasers generally employ tunable lasers which can be tuned to a specific absorption resonance of an atom or molecule (see Photochemical technology). Examples include the tunable dye laser in the ultraviolet, visible, and near-infrared portions of the spectmm the titanium-doped sapphire, Tfsapphire, laser in the visible and near infrared optical parametric oscillators in the visible and infrared and Line-tunable carbon dioxide lasers, which can be tuned with a wavelength-selective element to any of a large number of closely spaced lines in the infrared near 10 ]lni. 

Resonance forms do not imply different kinds of molecules with electrons shifting eternally between them. There is only one type of S02 molecule its structure is intermediate between those of the two resonance forms drawn for sulfur dioxide. 

Resonance Energies of Carbon Dioxide, Alkyl Isocyanates, etc. 

In the following discussion use is made of an equation that has been formulated by the method given earlier in a discussion of the equation for resonance between a single bond and a double bond11 and of the interatomic distances in the carbon monoxide molecule and carbon dioxide molecule.13 The potential function for the bond is assumed to have the form... 

For sulfur dioxide, with resonating Lewis structure... 

All of these uses are based on the behavior of titanium dioxide as a semiconductor. Photons having energies greater than v 3.2 eV (wavelengths shorter than 400 nm) produce electron/hole separation and initiate the photoreactions. Electron spin resonance (esr) studies have demonstrated electron capture by adsorbed oxygen to produce the superoxide radical ion (Scheme 1) (11). Superoxide and the positive hole are key factors in photoreactions involving titanium dioxide reported here are the results of attempts to alter the course of these photoreactions by use of metal ions and to understand better the mechanisms of these photoreactions. 

The sensor for the measurement of high levels of CO2 in gas phase was developed, as well90. It was based on fluorescence resonance energy transfer between 0 long-lifetime ruthenium polypyridyl complex and the pH-active disazo dye Sudan III. The donor luminophore and the acceptor dye were both immobilized in a hydrophobic silica sol-gel/ethyl cellulose hybrid matrix. The sensor exhibited a fast and reversible response to carbon dioxide over a wide range of concentrations. 

The dehydration of malonic acid, H02C-CH2-C02H, produces C302 (known as tricarbon dioxide or carbon suboxide). Draw the structure for C302 and describe the bonding in terms of resonance structures. 

Methyl-4-phenyl-l,2,5-thiadiazole 1,1-dioxide 21 suffers proton abstraction in basic nonaqueous media to give a resonance stabilized anion 43, neutralization of which using anhydrous TFA gives the orange tautomer 4-methylene-3-phenyl-l,2,5-thiadiazoline 1,1-dioxide 44 (Scheme 3) <2001JP0217>. The tautomeric equilibrium is practically displaced toward 21 in acetonitrile and toward 44 in DMF. 

A difference in reactivity was observed between the phenanthro[9,10-r]- and acenaphtho[l,2-c]-l,2,5-thiadiazole 1,1-dioxides 51 and 53 when treated with thiourea. The acenaphtho derivative 53 gave the expected addition product however, the phenanthro thiadiazole 51 was reduced to the thiadiazoline 1,1-dioxide 52 (Equation 2) <2004JP01091>. The difference in reactivity was attributed to the enhanced resonance stability offered by the phenanthrene group. 

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