Lecture 20: Order of Repulsion and Hybridization Involving d Orbitals
NH Electron Configuration of N
There is no Promotion required because there is no place to promote. Only 3 bonds can be formed. There is SP hybridization but 1 hybrid orbital is holding the lone pair. The other 3 is to hold the hydrogen bond. The molecule is derived from Tetrahedral. But one orbital is occupied by a lone pair so it is Trigonal Pyramid and the angle is 107
Order of repulsion
LP - LP > LP - BP > BP - BP
- When adding lone pairs the angle is smaller
Hybridization Involving d Orbitals
Promoting an electron from 3S to 3d orbital
AX type molecule - Trigonal Bi pyramid - dSP
SPd - 1 electron is promoted to d from 3S and the other from 3P
AX type molecules - Octahedral Structure - dSP
Why isn't a double bond twice the energy of a Single bond?
Because a double bond is on bond and one O bond and bond is weaker.
Three unpaired electrons can form 3 bonds but it forms 5 bonds
To do this we promote the S electron to the 3d orbital then has 5 unpaired electrons.
Why can't this happen with NCI ? Because it has 2S and 2P and there is no 2d orbital.
Now P undergoes dSP hybridization to give 5 orbitals. Each one contains an unpaired electron. These hybridized orbital are directed to the corners of a trigonal bi pyramid (AX )
Valence Bond Theory
Diamagnetic - All paired electrons, repelled
Paramagnetic - Unpaired electrons, attracted to magnetic field
All Paired electrons but is Paramagnetic (By Molecular Orbital Theory)