How do Covalent Bonds Produce Color?

In summary, the conversation discusses the Band Theory of metallic bonds and its relation to color production. It is mentioned that a metal like iron absorbs and emits a full range of colors due to metallic bonds, but the addition of oxygen or sulfur results in a different color. The explanation for this phenomenon is that the weak green color of iron II sulfate is due to transitions within the d-orbitals on iron, which does not involve covalent bonding. On the other hand, the color of substances like iron sulfide or iron oxide is mainly due to charge transfer transitions, where the bonding is mostly ionic. This transfer of charge from the negatively charged ligand to the metal requires both an energy corresponding to visible light and a high transition dipole
  • #1
Johnleprekan
57
0
I've learned about the Band Theory of metallic bonds and how they produce color, but how does a covalent bond produce color? Normally a metal such as iron absorbs and emits back the full range of colors due to metallic bonds, but when oxygen or sulfur get added it produces a different color. Can someone explain what happens here? One explanation for iron oxide and another for iron sulfate or iron sulfide, please. If possible explain in Layman's terms.
 
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  • #2
The weak green colour of iron II sulfate is due to transitions within the d-orbitals on iron, ie, covalent bonding is not involved. The colour of the other substances is mainly due to so called charge transfer transitions. The bonding in these compounds is mainly ionic and a transfer of charge from the negatively charged ligand (e.g. sulfide in iron sulfide or oxide in iron oxide) to the metal requires both an energy corresponding to visible light and goes in line with a high transition dipole moment.
 
  • #3
Thank you.
 

FAQ: How do Covalent Bonds Produce Color?

1) How do covalent bonds produce color?

Covalent bonds produce color through the absorption and emission of light. When an atom or molecule absorbs light, the electrons in the bonds are excited to a higher energy state. As these electrons return to their ground state, they release energy in the form of light, which we perceive as color.

2) What determines the color produced by covalent bonds?

The color produced by covalent bonds is determined by the energy difference between the ground state and the excited state of the electrons. This energy difference is specific to each molecule and is determined by the types of atoms involved and the arrangement of the bonds within the molecule.

3) Can covalent bonds produce different colors?

Yes, covalent bonds can produce a wide range of colors depending on the specific molecule. The color produced is dependent on the energy difference between the ground state and the excited state, which can vary depending on the atoms and bonds present in the molecule.

4) How does the presence of different atoms affect the color produced by covalent bonds?

The presence of different atoms in a molecule can significantly impact the color produced by covalent bonds. Different atoms have different electron configurations and bond strengths, which can affect the energy difference between the ground state and the excited state of the electrons. This, in turn, can result in different colors being produced.

5) Can covalent bonds produce color in all types of molecules?

Yes, covalent bonds can produce color in all types of molecules as long as there is an energy difference between the ground state and the excited state of the electrons. However, the color produced may not always be visible to the human eye, as some molecules may absorb or emit light in the ultraviolet or infrared regions of the electromagnetic spectrum.

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