Re: CCL:isolobal vs. isoelectronic

 At 9:47 AM -0400 18/10/01, Shobe, Dave wrote:
 
 However, CH2 would not be "isolobal" to BH3 or CH3+ because CH2 has a
 lone
 pair as well as an empty orbital.
 
 My text books state that isoelectronic means same number of electrons.
 USUALLY (not always) this implies same electronic configuration.
 by this definition, BH3, CH3+ and CH2 are isoelectronic.
 by extension, "isolobal" would mean same number/arrangement of lobes
 (ie near-same symmetry). CH4, NH3 (with lone pair) and H2O (with 2 lone pairs)
 are both isoelectronic and isolobal.
 note that this does not mean same symmetry since these molecules
 are Td, C3v and C2v.
 CH2 is a special case because it has two close electronic states
 singlet (lone pair and empty orbital) and doublet (diradical)
 BH3, CH3+ and singlet CH2 are both isoelectronic and isolobal.
 doublet CH2 has a very different electronic configuration.
 BH3, CH3+ and singlet CH2 are isoelectronic but not isolobal.
 At 9:47 AM -0400 18/10/01, Shobe, Dave wrote:
 
 I forget the name for the relationship among for example {HCN, HSiP, HCAs,
  >...} where atoms are replaced by others in the same column of the periodic
 table.
 
 At 8:56 AM -0700 18/10/01, Roy Jensen wrote:
 
 isovalent, I believe.
 
 Does "isovalent" refer to "valency"? Are NaCl and AgCl
 isovalent?
 I am not sure.
 I had heard (cannot remember where) and use "valence isoelectronic"
 but am very happy to be corrected if wrong.
 Kieran
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  Dr Kieran F Lim             Biol. and Chemical Sciences
  (Lim Pak Kwan)              Deakin University
  ph:  + [61] (3) 5227-2146   Geelong          VIC   3217
  fax: + [61] (3) 5227-1040   AUSTRALIA
  mailto:lim()at()deakin.edu.au    http://www.deakin.edu.au/~lim
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