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Sunday, December 27, 2020
Does 2s and 2p have the same energy?
Saturday, December 26, 2020
Which orbital has much overlap capacity?
Why the extent of overlap is more in 2p-3d than 2p-3p?
The order of overlapping strength of orbitals is given as:
2pπ-2pπ>2pπ-3dπ>2pπ-3pπ>3pπ-3pπ.
The strength of π-bond is directly proportional to the overlapping strength of orbitals because on greater overlapping distance between two nuclei decreases and bond strength increase hence order of π-bond also given as:
2pπ-2pπ>2pπ-3dπ>2pπ-3pπ>3pπ-3pπ.
2pπ-2pπ, π-bonding is stronger than 2pπ-3dπ, π-bonding due to the lower energy gap (n=2) between them.
The importance comparison is in between 2pπ-3dπ and 2pπ-3pπ. The overlapping strength of 2pπ-3dπ is more than 2pπ-3pπ this is due to fact that , the 3d orbitals have two lobes which are more bent than 3p orbitals. That why overlapping strength increase.
Friday, December 25, 2020
How to determine order of bond angle of Me-O-Me, H3Si-O-SiH3 and (ph)3Si-O-Si(Ph) ?
(1) Oxygen of Me-O-Me is sp3 hybridised so C-O-C bond angle is more than 109’28” approx 110” due to crowding of methyl group.
(2) In disilyl ether , oxygen is Sp2 hybridised and planer due to
back bonding between oxygen and silicon atom. In this back bonding lone pair of oxygen atom
donate to the vacant d orbital of silicon atom due to this fact bond lengths of Si-O is
decrease and increases (approx 140”).
(3) In (Ph)3Si-O-Si(Ph)3 compounds Si-O-Si bond angle is Approx 180 due to back bonding and hybridisation is Sp.
How to compared bond angle (C-N-C) and (Si-N-Si) in trimethyl amine and trisilyl amine respectively?
Nitrogen (N) atom in trimethyl amine [N(CH3)3] is sp3 hybridised and tetrahedral ( bond angle ~107) due to non bonding electron pair of N is localised (more basic). On the other hand N atom of trisilyl amine [N(SiH3)3] is sp2 hybridised and trigonal planner (bond angle~120).This is due to the participation of non-bondlng pair of N into pπ-dπ back banding. Due to this delocalization of non-bonding electron pair of N in trisilyl amine it is also less basic