Ralph G. Pearson

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Ralph G. Pearson (born January 12, 1919 in Chicago ) is an American chemist. He became known for his work in the field of theoretical inorganic chemistry. Since 1976 he has taught at the University of California, Santa Barbara .

HSAB concept

The HSAB concept introduced by Pearson in the 1960s explains that ions of soft acids (great polarizability ) preferentially combine with ions of soft bases . Ions of hard acids (low polarizability) preferentially combine with ions of hard bases.

Principle of maximum hardness

Pearson's principle of maximum hardness states that the most stable chemical compounds have the largest possible energy gap between HOMO and LUMO . These are the compounds with the maximum chemical hardness. For example, the HOMO-LUMO energy gap with tetrahedral methane is much larger than with the planar form. The general applicability of this principle is questioned in the literature.

Honors

Pearson has been a member of the National Academy of Sciences since 1974 .

Works

  • RG Pearson (1973). Hard and Soft Acids and Bases. Dowden, Hutchinson and Ross. ISBN 0-87933-021-X
  • RG Pearson (1997). Chemical hardness. Wiley-VCH publishing house, Weinheim. ISBN 3-527-29482-1

Web links

Individual evidence

  1. ^ Ralph G. Pearson: Recent Advances in the Concept of Hard and Soft Acids and Bases . In: Journal of Chemical Education . tape 64 , no. 7 , 1987, pp. 561-567 , doi : 10.1021 / ed064p561 .
  2. ^ KL Sebastian: On the proof of the principle of maximum hardness . In: Chemical Physics Letters . tape 231 , no. 1 , 1994, p. 40-42 , doi : 10.1016 / 0009-2614 (94) 01210-5 .
  3. ^ Homepage of Ralph G. Pearson
personal data
SURNAME Pearson, Ralph G.
BRIEF DESCRIPTION American chemist
DATE OF BIRTH January 12, 1919
PLACE OF BIRTH Chicago