LETTERS
To the Editor: There is a t present some variation in the usage of the terms "acid" and "base." Most interested parties fall into one of two groups: (1) Those who feel that the unmodified nouns should refer to Lowry-Bronsted acids and bases only. The more liberal of this group will use the expression "Lewis acid-base systems"' when appropriate; others prefer the longer, more descriptive "electron donorelectron accept~r."~ (2) Those who use unmodified "acid-base" for all Lewis svstems. and for Lowrv-Bronsted systems. The latter &e somktimes called s&ondary acids and bases, since they can only be described as Lewis acids and bases by a rather drastic modification of the electron donor-electron acceptor definition. A superficial review of the literature suggests that most authors, for the convenience of brevity, prefer to use unmodified "acid-base" to mean systems of the sort in which they are most intere~ted.~Those who do not, have usages which often depend on their countries of origin. This is clearly an unsatisfactory state of affairs,& and one which causes considerable unnecessary confusion to students. It would be helpful to bring into use nomenclature which is precise and convenient. There is a strong case, both on historical grounds and because of common usage, for referring to protonic systems as acids and bases. We should perhaps use a definition for these words such as the original (1923) Lowry-Bronsted definition5 " A n acid is a species having a tendency to lose a proton, and a base is a species having a tendency to add on a proton." For Lewis systems, the terms "donor" and "acceptor" are well established and descriptive and could be encouraged by the introduction of (analogous to "red-ox") the corruption "don-ace" (pronounced 'doanack') to indicate "electron donor-electron acceptor" or "Lewis acid-base." We cannot hope to remove confusion immediately; no doubt some well-established opinions will resist any 'See, for example, HINE, J., ' ' P h ~ ~ ~ i cOrganic al Chemistry," 2nd ed., McGraw-Hill Book Co., Inc., New York, 1962, p. 44. See, for example, BELL, R. P., "Acids and Bases," John Wiley & Sons, Inc., New York, 1952, p. 88. a DUMPTY, H., &S reported by DonGso~,C. L., "Through the Looking Glass," Pocket Books, New York, 1951, Chap. VI. C. L., "Alice's 'HARE, M., ET AL., as reported by DODGSON, Adventures in Wonderland," Pocket Books, New York, 1951, Chap. VII. See footnote 1, p. 43 (original journals cited): also see footnote2, p. 8.
change. Certainly the later it arrives the more difficult a reform will be. However, if a nomenclature such as the one outlined above, or perhaps some superior version prompted by its suggestion, were to be adopted by educators now, we might hope for some improvement during the next generation.
To the E d i t o ~ : I n light of the recent interest in the use of computers to solve equilibrium constant problems [for example, THISJOURNAL, 42, 127, 131, 620, 622, 624 (1965)l may I point out that the method of Block and NcIntyn. [J.A m . Chem. Sac., 75, 5667(1033)] allows direct computation of protonation constants and of metal-ligand formation constants for reactions up to three steps with no iteration at all. Programs in FORTRAN for use on small computers have been written for both metal-amine and metal-anionic ligaud computations [Goldberg, D. E., THIS JOURN.LL, 39, 328(1962); 40, 341(1963)] and are available from the undersigned.
To the Editor The following comments apply to both your features, l'Textbool
