2s and hydrogen 1sAO's, is the orbital ofthe strongest bonding nature (it has the lowest orbital energybin OH? and thc m n l h i n : i t i m of thr X2s and hydrogen 1s nrh~talsdocs not Irsd tu an MU with an elterrive bonding chnr;lctt.r. Based on the data assembled in thetable, conclusions on t h e stahilitv of members of isoelectronic series can be drawn and used in teaching general and inorganic chemist ~If .the interacting AO's of atoms.. res~onsiblefor bond formation in molecules and ions, differ in energy so t h a t
FHF
-
Related to E(02p)= -1 3.6.E(HIs) =-I 3.6 Lall v lu sex ressed in eVl NH' e ~ HF ~ P HNet
HX"
A
AE
< 7 eV, the molecules and ions are redax-stable and, depending an their charge, they can participate in aeidbase reactions (compare, for example, the basicity of the anions BO$-, Cog-, and NOa). b. 7 < AE < 11,the molecules and ions can exist and are stable under some conditions. They exhibit a tendency to react to yield produds with s lone pair localized an the central atom X, usually of Xns nature. Protolytic changes of NH; to NH, or reductions of NO; to NO; and NO, producing particles with a N2s lane pair, serve as examples. c. AE > 11 eV, the molecules and ions either do not exist or are very unstable. As an example, molecules such as Ar04 and 003and ions F Q and N e @ can he shown. Such particles might, however, be formed as intermediates in some chemical processes. a.
A 0 Energies (6)and Their Difference for Members of Some lsoelectronic Series
The above energy differences should be taken a s rough borders and there may be many molecules t h a t need not obey expectations based on the given specific energy values. For molecules constructed from atoms with a wider base of close-lying AO's (elements of higher periods), other factors can play a n important role in t h e stability of their
molecules. The proposed conclusions may be of a more general relevance and also apply outside isoelectronic series.
Literature Cited E;Atkina. P. W :Lsngford. C. H . Innrgonie Chrmktry; Oxford University pless: oxfod. 1990. 2. Cotton. E A,; Wilkinson. G. A d v o n e d Inorganic C h ~ m i a f w .5th ed.; Wiley: New 1. Shriver. D.
..,
Ynrl l Q P P
3. k. J. D. Concis~lnorgonicChemist?, 4th ed.:Chapman and Hall: New Vork. 1991. 4. Mackaa K M.; Mackay R. A. lnlroducl~oal o Modem Inorgnnir Chamretry, 4th ed.: Blackie: London. 1989. 5 . Ebbing, D. D. Genemi Chemislry. 2nd ed.; Houghton: Barton. 1987. 6. Bliggs, D.HondhoA o,fX-Roy and Ullmuiolet S ~ e l r o - c o p y :Heyden: London. 1977. 7. V0gler.A.; Wright. R. E.; Kunkely,H.AngewChem. 1380.19.717-720. 8. Engelke, R. J. Phys Cham. 1992,96,10789-10792.
Volume 72 Number 4 April 1995
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