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One of Pauling's examples is olivine, M 2 SiO 4, where M is a mixture of Mg 2+ at some sites and Fe 2+ at others. The structure contains distinct SiO 4 tetrahedra which do not share any oxygens (at corners, edges or faces) with each other. The lower-valence Mg 2+ and Fe 2+ cations are surrounded by polyhedra which do share oxygens.
Pauling calculated the charge build up on the silicon atom due to the difference in electronegativity to be +2. The electroneutrality principle led Pauling to the conclusion that charge transfer from O to Si must occur using d orbitals forming a π-bond and he calculated that this π-bonding accounted for the shortening of the Si-O bond.
The bond valence method is a development of Pauling's rules. In 1930, Lawrence Bragg [11] showed that Pauling's electrostatic valence rule could be represented by electrostatic lines of force emanating from cations in proportion to the cation charge and ending on anions. The lines of force are divided equally between the bonds to the corners of ...
The electrostatic valency is a measure of the strength of bonds, being the valence charge divided by the coordination number. [citation needed] Linus Pauling's second rule of ionic bonding, the Electrostatic Valence Principle states, "An ionic structure will be stable to the extent that the sum of the strengths of the electrostatic bonds that reach an anion equals the charge on that anion."
Linus Carl Pauling FRS (/ ˈ p ɔː l ɪ ŋ / PAW-ling; February 28, 1901 – August 19, 1994) [4] was an American chemist, biochemist, chemical engineer, peace activist, author, and educator. He published more than 1,200 papers and books, of which about 850 dealt with scientific topics. [5]
Electrostatic potential map of a water molecule, where the oxygen atom has a more negative charge (red) than the positive (blue) hydrogen atoms. Electronegativity, symbolized as χ, is the tendency for an atom of a given chemical element to attract shared electrons (or electron density) when forming a chemical bond. [1]
Pauling estimated that an electronegativity difference of 1.7 (on the Pauling scale) corresponds to 50% ionic character, so that a difference greater than 1.7 corresponds to a bond which is predominantly ionic. [10] Ionic character in covalent bonds can be directly measured for atoms having quadrupolar nuclei (2 H, 14 N, 81,79 Br, 35,37 Cl or ...
Periodic variation of Pauling electronegativities. The tendency of an atom in a molecule to attract the shared pair of electrons towards itself is known as electronegativity. It is a dimensionless quantity because it is only a tendency. [16] The most commonly used scale to measure electronegativity was designed by Linus Pauling.