In sp3 hybridisation it forms tetrahedron shape . but is that one be possible?

Question

the angle of tetrahedron shape is 109'28''.that is if u measure angle between tetrahedron's any two arms the angle would be 109'28''.it has one dominating pair having higher repulsive force compared to others that is indicated on the top of the atom while representing.considering this if we see the tetrahedron then u cant form it ,that is it has one angle more than 109'28''.considering 3 bonded arms being at 109'28'' with one arm they form a circle which can only make equal angles of 120'.if 3 arms are at 109'28'' then the angle between one bond wont be 109'28''.also in other plane wise considering we wont get the required angle.(one of my teachers agreed with what is said and others said my statement is not true and impossible )can any one tell me is it possible if iti is please explain the concept to me

Answer 1

I'm a little confused by your statement, but let me see if I can help. In sp3 hybridization there are 4 things (bonds or non-bonding pairs of electrons) surrounding the central carbon atom. If there are 4 bonds (like in methane (CH4)), then these bonds are spread as far apart from each other which does give a bond angle of about 109degrees, as you stated. These four bonds will form the arms of a perfect tetrahedron. All of the bond angels in a molecule like methane will be the same and all of them will be the 109+ degrees.

I think your issue is that if you look at any 3 of the atoms bonded to the central atom, they will all sit on the circumfrence of a circle. However, the central atom IS NOT in the same plane as the other atoms. That's why the bond angles are not 120. IF the central atom was at the center of the circle, then you would have 120 degree bond angles. But because it is elevated above the circle, the bond angles are reduced.

Hope this helps...

Answer 2

"perfect" sp3 and sp2 hybridization only happen with equal substituents around the central atom; when you have a molecule like chloroform, though, the hybridization differs among the bonding orbitals. This was my project for Physical Chemistry; I wrote a computer program that determined the hybridization for bonding orbitals given the bond angle.

I hope you find the web page below more enlightening than confusing: