Bond angles ethylene oxide

Incorporating an oxygen atom into a three membered nng requires its bond angle to be seriously distorted from the normal tetrahedral value In ethylene oxide for exam pie the bond angle at oxygen is 61 5°... 

The stmctural parameters of ethylene oxide have been determined by microwave spectroscopy (34). Bond distances iu nm determined are as follows C—C, 0.1466 C—H, 0.1085 and C—O, 0.1431. The HCH bond angle is 116.6°, and the COC angle 61.64°. Recent ah initio studies usiug SCF, MP2, and CISD have predicted bond lengths that are very close to the experimental values (35,36). 

Regioselective crosslinking of the core domain of cylindrically shaped, wormlike micelles composed of poly[(butadiene)45-b-(ethylene oxide)55] and assembled in aqueous solution at < 5% block copolymer concentrations, was performed using radical coupling of the double bonds throughout the poly(butadiene) phase [27] (Figure 6.3b). This resulted in a 13% reduction in the core diameter, from 14.2 to 12.4 nm, as measured by small-angle neutron scatter-... 

Ethylene oxides, like other three-membered ring systems, possess many singular features that invite a basis in theory. To satisfy Hub demand, much effort has boon devoted to the task of determining with precision such fundamental properties of the molecule os bond lengths, bond angles, and bond energies- With the advent of modern instrumental methods it has been possible to develop a dependable physical basis fin- theoretical speculations on the electronic structure of ethylene oxide. The present section is concerned with this aspect of epoxide chemistry. 

Aqueous solutions of poly(ethylene oxide), (-CH20CH2-)m (PEO) exhibit unusual phase behavior in the sense that the polymer is soluble in water at room temperature, but phase separates at higher temperatures. Molecular interpretations of this unusual behavior implicate the effect of hydration on the conformational equilibria of the polymer chains based on studies of conforma-honal equilibria of small-molecule analogs of PEO e.g., 1,2 dimethoxyethane (DME), CH3OCH2CH2OCH3. Note that DME conformations are characterized by three consecutive dihedral angles centered on the 0-C, C-C, and C-0 bonds along the chain backbone, which can be found in the trans t, 180°),... 

Two bonds formed by a N atom having one or two lone pairs would be expected to be angular with bond angles of 120 (one lone pair, sp bonds) or 109 (two lone pairs, sp bonds). (Molecules such as diazirine (cyclic diazomethane) and perfluorodiazirine are special cases like cyclopropane or ethylene oxide.) If the... 

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