Dipole The separation of positive and negative

Induced dipole. The separation of positive and negative charges in a neutral atom (or a nonpolar molecule) caused by the proximity of an ion or a polar molecule. (11.2)... 

What attractive interaction occurs in nonpolar substances To leant the answer to this question, consider the arrangement shown in Figure 11.4. If we place an ion or a polar molecule near an atom (or a nonpolar molecule), the electron distribution of the atom (or molecule) is distorted by the force exerted by the ion or the polar molecule, resulting in a kind of dipole. The dipole in the atom (or nonpolar molecule) is said to be an induced dipole because the separation of positive and negative charges in the atom (or nonpolar molecule) is due to the proximity of an ion or a polar molecule. The attractive interaction between an ion and the induced dipole is called ion-induced dipole interaction, and the attractive interaction between a polar molecule and the induced dipole is called dipole-induced dipole interaction. 

The dipole generated in the atom or nonpolar molecule is said to be an induced dipole because the separation of positive and negative charges in the atom (or nonpolar molecule) is due to the proximity of an ion of a polar molecule. The magnitude of the induced dipole moment, /tinj, is proportional to the strength of the electric field, E, generated by the ion or polar molecule... 

A dipole moment can be momentarily induced in an otherwise nonpolar molecule or bond by a polar molecule, ion, or electric field. The polar molecule or ion creates an electric field, which pushes the electrons and nuclei in opposite directions, separating the centers of positive and negative charge. Such dipole moments are called induced dipoles. Induced dipoles are common in nature and are generally weaker than permanent dipoles. 

Induced dipole-induced dipole interactions, also called London forces, result when a nonpolar molecule undergoes a distortion, perhaps as a result of a collision, which results in a momentary separation of the centers of positive and negative charge. The resulting dipole induces a dipole in a neighboring molecule, resulting in an attractive interaction. 

This approach, which is certainly not exact, breaks down badly if extended to predominantly covalent bonds. To evaluate the degree of ionic character in such bonds if they occur in simple molecules, Pauling has used dipole moments. The term dipole has already been applied to the water molecule, a molecule in which there is a separation between the centers of positive and negative charge (Chap. 4). When the charges are equal in magnitude, the dipole moment, ju, is defined... 

In a medium of dielectric constant K this force is weakened to e e jKr. The weakening can come about in two ways. First, the field induces a separation of positive and negative charges in the molecules in such a way as partially to neutralize itself. Secondly, the field causes orientation of molecules possessing natural dipoles, which set themselves in opposition to it and counteract its influence. 

London dispersion forces are Instantaneous dipole forces that arise when the electron clond of an atom is momentarily distorted by a nearby dipole, temporarily separating the centers of positive and negative charge in the atom. 

Photochemistry deals with the interaction of electromagnetic waves of visible and UV wavelength with the electrons in chemical structures. These interactions are predominantly through the effect of the electric field on electric dipoles— structures in which there is a separation of positive and negative charge, such as atoms and molecules. These are termed electric dipole interactions, or, when they result in a change of state, electric dipole transitions. Such transitions are the most important processes involved in production of electronic excited-states. The... 

The positive character of the (3 carbon suggested by the resonance description is consistent with numerous differences between a,(3-unsaturated carbonyl compounds and their non-conjugated relatives. Consistent with its greater separation of positive and negative charge, fran -2-butenal has a larger dipole moment than butanal. 

A common method of chemically separating refinery or petrochemical soil components uses their different solubilities. Some components will preferentially partition into a polar solvent, while others will be soluble in nonpolar solvents. Solvents are classified as polar and nonpolar by their molecular structure. A polar solvent consists of dipoles. Dipoles are molecules in which the atoms are positioned so the centers of positive and negative electrical charges are at different locations in the molecule. Water is the most common polar solvent. 

We quantify the polarity of a bond by the size of its dipole moment. A dipole moment (fi) occurs any time there is a separation of positive and negative charge. The magnitude of a dipole moment created by separating two particles of equal but opposite charges of magnitude g by a distance r is given by the equation ... 

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