The valence-bond model and the crystal field theory explain some aspects of the chemistry of the transition metals, but neither model is good at predicting all of the properties of transition-metal complexes. A third model, based on molecular orbital theory, was therefore developed that is known as ligand-field theory. Ligand-field theory is more powerful than either the valence-bond or crystal-field theories. Unfortunately it is also more abstract.

The following list summarizes the key concepts of Ligand Field Theory.

1)One or more orbitals on the ligand overlap with one or more atomic orbitals on the metal.
2)If the metal- and ligand-based orbitals have similar energies and compatible symmetries, a net interaction exists.
3)The net interaction produces a new set of orbitals, one bonding and the other antibonding in nature. (An * indicates an orbital is antibonding.)
4)Where no net interaction exists, the original atomic and molecular orbitals are unaffected and are nonbonding in nature as regards the metal-ligand interaction.
5)Bonding and antibonding orbitals are of sigma (σ) or pi (π) character, depending upon whether the bonding or antibonding interaction lies along the line connecting the metal and the ligand. (Delta (δ) bonding is also possible, but it is unusual and is relatively weak.)

A more detailed description of bonding in coordination compounds is provided by Ligand Field Theory. In coordination chemistry, the ligand is a Lewis base, which means that the ligand is able to donate a pair of electrons to form a covalent bond. The metal is a Lewis acid, which means it has an empty orbital that can accept a pair of electrons from a Lewis base to form a covalent bond. This bond is sometimes called a coordinate covalent bond or a dative covalent bond to indicate that both electrons in the bond come from the ligand.did u know The principles of Ligand Field Theory are similar to those for Molecular Orbital Theory.

Could you help me understand where the valence-bond model and the crystal field theory fall apart with the transition metals. That is sort of where I get lost, do you know anywhere on the web where this is explained?

In general, please provide some details about what you're describing, so that others will be able to understand what you mean, and be able to respond accordingly. You can edit your original post, to better guide the discussion.

Do you mean ligand field theory? It has been touched on in my AP chemistry course, and I would love to talk more about it. In general the behavior of transition metals, is hard for me to keep strait. They form covalent bonds, and ionic ones, and coordination complexes seem like a blend of the two. I might be wrong there, but I would talk about ligand field theory.

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TopNewestThe valence-bond model and the crystal field theory explain some aspects of the chemistry of the transition metals, but neither model is good at predicting all of the properties of transition-metal complexes. A third model, based on molecular orbital theory, was therefore developed that is known as ligand-field theory. Ligand-field theory is more powerful than either the valence-bond or crystal-field theories. Unfortunately it is also more abstract.

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i wanted to know about the applications of this theory......??

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The following list summarizes the key concepts of Ligand Field Theory.

1)One or more orbitals on the ligand overlap with one or more atomic orbitals on the metal. 2)If the metal- and ligand-based orbitals have similar energies and compatible symmetries, a net interaction exists. 3)The net interaction produces a new set of orbitals, one bonding and the other antibonding in nature. (An * indicates an orbital is antibonding.) 4)Where no net interaction exists, the original atomic and molecular orbitals are unaffected and are nonbonding in nature as regards the metal-ligand interaction. 5)Bonding and antibonding orbitals are of sigma (σ) or pi (π) character, depending upon whether the bonding or antibonding interaction lies along the line connecting the metal and the ligand. (Delta (δ) bonding is also possible, but it is unusual and is relatively weak.)

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A more detailed description of bonding in coordination compounds is provided by Ligand Field Theory. In coordination chemistry, the ligand is a Lewis base, which means that the ligand is able to donate a pair of electrons to form a covalent bond. The metal is a Lewis acid, which means it has an empty orbital that can accept a pair of electrons from a Lewis base to form a covalent bond. This bond is sometimes called a coordinate covalent bond or a dative covalent bond to indicate that both electrons in the bond come from the ligand.did u know The principles of Ligand Field Theory are similar to those for Molecular Orbital Theory.

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i too dont know about it Grace......... i wanted it to dicuss here because i too want to know about it

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Ayushi,

Could you help me understand where the valence-bond model and the crystal field theory fall apart with the transition metals. That is sort of where I get lost, do you know anywhere on the web where this is explained?

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In general, please provide some details about what you're describing, so that others will be able to understand what you mean, and be able to respond accordingly. You can edit your original post, to better guide the discussion.

Log in to reply

Ayushi,

Do you mean ligand field theory? It has been touched on in my AP chemistry course, and I would love to talk more about it. In general the behavior of transition metals, is hard for me to keep strait. They form covalent bonds, and ionic ones, and coordination complexes seem like a blend of the two. I might be wrong there, but I would talk about ligand field theory.

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