Abegg's rule

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In chemistry, Abegg’s rule states that the difference between the maximum positive and negative valence of an element is frequently eight. In general, for a given chemical element (as sulfur) Abegg’s rule states that the sum of the absolute value of its negative valence of maximum absolute value (as −2 for sulfur in H₂S) and its positive valence of maximum value (as +6 for sulfur in H₂SO₄) is often equal to 8. The rule was formulated in 1904 by German chemist Richard Abegg. It was used as a basis of argument in Gilbert Lewis’ 1916 famous article "The Atom and the Molecule", an article which later inspired Linus Pauling to write the famous 1938 textbook The Nature of the Chemical Bond. Lewis used this rule to develop his cubical atom theory, which later developed into the octet rule. Abegg’s rule is sometimes referred to as "Abegg’s law of valence and countervalence".