What is "abegg's rule"

n. (context chemistry English) A rule in chemistry that states that the sum of the hydrogen valence and the maximum oxygen valence is equal to eight.(R:MW3 1976: page=3)

In chemistry, Abegg’s rule states that the difference between the maximum positive and negative valence of an element is frequently eight. The rule used a historic meaning of valence which resembles the modern concept of oxidation state in which an atom is an electron donor or receiver. Abegg’s rule is sometimes referred to as "Abegg’s law of valence and countervalence".

In general, for a given chemical element (as sulfur) Abegg’s rule states that the sum of the absolute value of its negative valence (such as −2 for sulfur in HS) and its positive valence of maximum value (as +6 for sulfur in HSO) is often equal to 8.