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An application of HSAB theory is the so-called Kornblum's rule (after Nathan Kornblum) which states that in reactions with ambident nucleophiles (nucleophiles that can attack from two or more places), the more electronegative atom reacts when the reaction mechanism is S N 1 and the less electronegative one in a S N 2 reaction.
Hard metal cations, as classified by HSAB theory, tend to form N-bonded complexes (isothiocyanates), whereas class B or soft metal cations tend to form S-bonded thiocyanate complexes. For the isothiocyanates, the M-N-C angle is usually close to 180°. For the thiocyanates, the M-S-C angle is usually close to 100°.
The HSAB theory, though useful, is only semi-quantitative. [28] The hardness of a metal ion increases with oxidation state. An example of this effect is given by the fact that Fe 2+ tends to form stronger complexes with N-donor ligands than with O-donor ligands, but the opposite is true for Fe 3+.
[2] [17] The Brønsted–Lowry acid–base theory was published in the same year. The two theories are distinct but complementary. A Lewis base is also a Brønsted–Lowry base, but a Lewis acid does not need to be a Brønsted–Lowry acid. The classification into hard and soft acids and bases (HSAB theory) followed in 1963.
In geometry, Thales's theorem states that if A, B, and C are distinct points on a circle where the line AC is a diameter, the angle ∠ ABC is a right angle. Thales's theorem is a special case of the inscribed angle theorem and is mentioned and proved as part of the 31st proposition in the third book of Euclid 's Elements . [ 1 ]
Oxophilicity is often stated to be related to the hardness of the element, within the HSAB theory (hard and soft (Lewis) acids and bases), but it has been shown that oxophilicity depends more on the electronegativity and effective nuclear charge of the element than on its hardness. [1]
Before we explain this incorrectness, let us examine a little of the principles of HSABs: Pearson is the one who created the HSAB theory, based on the principle: Hard acids can react well with hard bases, amd soft acids with soft bases. The following is a table of common HSABs. Blnguyen (bananabucket) 03:53, 21 November 2006 (UTC)
Möbius geometry is the study of "Euclidean space with a point added at infinity", or a "Minkowski (or pseudo-Euclidean) space with a null cone added at infinity".That is, the setting is a compactification of a familiar space; the geometry is concerned with the implications of preserving angles.