i read in my textbook that the energy diagram of moleculal orbits is different for atoms nitrogen and below them. my question is which one of the energy diagrams to use in heteronuclear compounds like CO?
-
$\begingroup$ I'm assuming you only looked at homonuclear molecules ($\ce{O2}$, $\ce{H2}$) so far. The atomic orbitals are of rather different energies in $\ce{C}$ and $\ce{O}$ just because the nuclear charge is different (consider the ionization energies). That is why I don't expect anyone to produce a decent orbital diagram without performing some quantitative computational chemistry first. $\endgroup$– TAR86Mar 22, 2019 at 6:43
2 Answers
(In heteronuclear diatomic molecules, atomic orbitals only mix when the electronegativity values are similar.)
(While MOs for homonuclear diatomic molecules contain equal contributions from each interacting atomic orbital, MOs for heteronuclear diatomics contain different atomic orbital contributions.)
(Orbital interactions to produce bonding or antibonding orbitals in heteronuclear diatomics occur if there is sufficient overlap between atomic orbitals, as determined by their symmetries and similarity in orbital energies.)
It depends on how many electrons your compound has. In $\ce{O2}$ , there are 16 electrons. Likewise all compounds with more than 16 electrons follow the $"\ce{O2}"$ diagram and those with less than 16 follow the other diagram.