What is backbonding?
This type of bonding occurs between atoms in a compound in which one atom has lone pair of electron and the other has vacant orbital placed adjacent to each other.A compound with back bonding has pi-bonding character since it results after formation of sigma bond.Back bonding allows the molecule to stable as it completes its octet. Back bonding results in a decrease in bond length and increase in bond order.π backbondingIn π backbonding the electrons move from an atomic orbital on one atom to a π* anti-bonding orbital on another atom or ligand.Such type of bonding is common in organometallic chemistry of transition metals which have multi-atomic ligands such as carbon monoxide, ethylene or the nitrosonium cation.The electrons from the metal are used to bond to the ligand in order to release the metal from excess negative charge.Ni(CO) and Zeise’s salt are compounds in which π back bonding occurs.
Fundamental and basic explanation for BACKBONDIN in certain chemical compounds?
Backbonding usually appears in metal complexes. When forming a complex the ligands bond to the central metal with their sigma electrons, and almost always there is a backbonding from the metal's side in which electrons move from their atomic orbits to an anti-bonding (Pi*) orbit around the ligand. In this process the bonding between the metal and the ligand becomes stronger (though the ligand itself will be at a higher energy state since there will be an anti-bonding orbit occupied). This backbonding will greatly affect the electron structure of the complex resulting in their unique spectral features. It happens in almost all transition metal complexes like Ni(CO)4, [Fe(CN)6]4- I know this answer won't help much to understand essence of backbonding but it would need a bit of knowledge of theoratical chemistry and scetroscopy to explain it better.
How can BF3 form a back bonding? What is the mechanism?
Boron has three valence electrons. 2 electron in 2s and 1 in 2p say 2px. One of electron is promoted to p orbital say 2py. Now they will intermix forming three sp2 hybrid orbitals. These will direct themselves on the corner of triangle forming BF3.BF3 though neutral but boron is electron deficient because of incomplete octet in BF3. Florine has three lone pairs. One of the lone is shared between boron vacant orbitals say 2pz. This is how back bonding occurs in BF3.The electrons of all three florine will be used one by one and over all structure will look like above left handed.Hope so that you may understand it.Welcome…
Is there back bonding possible in PF3?
Yes back bonding occurs in PF3, (it is one of the most common examples) as Phosphorus has vacant d-orbitals and each Flourine has 3 lone-pairs of electron.In general you, every compound in which central atom has vacant orbitals and adjacent atoms(some cases molecules too) have lone pair of electrons (having complete octet) back bonding occurs, with few exceptions. Back bonding occurrence decreases with increase in size of atoms. Other examples are BCl3, PCl3, etc.Anyone may correct me, if you may find me wrong in any statement I made.
Why does back bonding occur?
π backbonding is also called π backdonation. It can be defined as follows,In which electrons move from an atomic orbital on one atom to a π* antibonding orbital on a π-acceptor ligand.Back bonding is effective when the size of the valence shell matches.Generally, backbonding can be defined as it is the lone pair of electrons keep jumping between the metals. This provides the lone pair of electrons more number of exchange positions . As a result, the molecule becomes more stable.
What is Back Bonding and pπ–dπ in Chemical Bonding ?
I had been revising my chemistry notes and came across the word "Back Bonding" and in it I also saw pπ–dπ bonding in the molecule of N(SiH3 )3 . I cannot understand all this. Can anybody please help and explain this?
What is pπ-pπ bonding?
If there is bonding between two atoms where one atom is having one vacant orbital and another is having one lone pair of electrons, then this electron pair is donated to that respective vacant orbital. This type of bonding is called p π – p π or p π - d π depending on the orbital to which the electron pair is donated and from which the electron pair is donated. For example: bonding in SO3.In gas phase SO3 molecule is triangular planar involving sp2 hybridization of the S atom.There are three sigma bonds formed by sp2-p overlap and three pi bonds, one by p π – p π overlap and two by p π - d π overlap.
Why does not back bonding occur in OF2?
Back bonding is dative(coordinate) π- bonding.For it to occur, the essential requirement is presence of vacant orbital and lone pair orbital on two directly bonded atoms respectively.If you examine the structure of OF2, both are second period elements so these elements have “no” d- orbitals (their valence orbitals are only one 2s orbital and three 2p -orbitals.)Each fluorine here, forms one sigma bond and has three lone pairs.Oxygen atom is involved in two sigma bonds and has two lone pairs.So as you can see, no vacant orbital is available to accept lone pair and form coordinate bond.Hence no back bonding in such cases.Note- BF3 does have back bonding due to one vacant 2p orbital on boron atom which can accept lone pair from fluorine.