polar covalent bond - is one form of chemical bonds between the atoms of the material through which the molecules are formed.If the word "communication" problems in understanding does not occur, the terms "covalent" and "Polar" untrained person is unknown (of course, provided that the curriculum is not forgotten Chemistry).
So, the word "covalent" is derived from "ko-" and "-valenta", which literally means a one-directional strength.Indeed, it is the force that is able to combine two atoms in the molecule, reconfiguring their electronic shell in a single structure.Since both cores are equal, rotating around electrons fill not only the 'external' side, but also the space between the atoms.We can say that he is a covalent bond.At the same time such a dual system tends to perfection electron configuration as the carriers complete the shell of the interacting atoms.Note that a pair of electrons implements this type of communication.
Another version of the same phenomenon can be called an ionic type of bond.As the ion is formed when an atom loses an electron, it occurs when the exchange of negative charge carriers, which is typical for atoms of different substances (for example, fluorine and sodium).
polar covalent bond - is an intermediate option.This kind of resembles a "purely covalent" that is formed by molecular orbital (union of orbits), and from there partially ionic "tug" carriers.Pair shifted to one atom, but does not completely leave the area of another.Example involving polar covalent bond - water molecule.Finished shell are created by combining one atom of oxygen and two of hydrogen.However, since oxygen has a more pronounced ability to attract electrons of the pair is biased to the core of the "O".Incidentally, it is not necessary atoms form a pair of electrons can be two, three, etc.Covalent polar bond creates in the charge distribution (partial), and, as a consequence, the polarity.There is oriented molecules of the lines of the field strength.We can say that because of this there is a kind of distribution molecular dipole.His moment (mu) and generates an electric field intensity.A number of formulas for calculation of the dipole moment (in particular, the product of the distance to the charge), they can calculate a value defined by the polarity of the molecule.
In other words, the polar covalent bond can be formed by the atoms electronegativity which although different, but not enough to form an ionic bond.Let us explain what electronegativity.This term refers to the ability of an atom to attract to its core formed (-th) a couple of negative charge carriers.Obviously, in accordance with the law of conservation of energy, the more the interatomic bonds, the less their length.Typically, polar covalent bond is characteristic of atoms, chemical characteristics are similar.It is characterized by spatial orientation.This enables the formation of not only molecules but also crystal lattice in which atoms are arranged in a geometrically correct order.
Since the connection, in fact, is a superposition of two (or more) of the electron clouds belonging to different atoms, its strength depends mainly on how much are superimposed.It is not difficult to understand that by creating pairs, internuclear interval value of the electron density increases.
