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"ionic character"

Posted: Fri Nov 02, 2018 11:14 am
by 305154707
My lecture notes say that an increasing difference in electronegativity leads to an increasing ionic character of a covalent bond. Am I right when I say that all ionic bonds have a degree of covalent character or are they completely separate distinctions?

Re: "ionic character"

Posted: Fri Nov 02, 2018 11:59 am
by Xinyi Zeng 4C
I think so!
As of my understanding, I think ALL ionic compounds have a degree of covalent character. I don't think pure ionic bonds really exist, as this would require an infinitely large electronegativity difference, and complete charge transfer is unfavorable considering the raising of the electronic kinetic energy.
And, all bonding interactions have some covalent character because the electron density remains shared between the atoms. The degree of ionic versus covalent character of a bond is determined by the difference in electronegativity between the constituent atoms. The larger the difference, the more ionic the bond. The smaller the difference, the more covalent the bond. Bonds that fall in between the two extremes, having both ionic and covalent character, are classified as polar covalent bonds, which was discussed in the lecture today.

Re: "ionic character"

Posted: Fri Nov 02, 2018 2:15 pm
by hazelyang2E
Yes! I believe that your assumptions would be correct based on what Professor Lavelle taught in lecture. He introduced the concepts of correcting BOTH the covalent and iconic models. For covalent models, he discussed the fact that electron pairs in covalent bonds may not be equally shared all the time. For ionic models, he discussed how all ionic bonds have at least some degree of ionic character, and then went into greater detail about ions that are highly polarizable which result in ionic bond with more covalent character versus ions with high polarizing power which cause large distortions in the ionic bond. Hopefully this helps to clarify/confirm your thoughts!

Re: "ionic character"

Posted: Sat Nov 03, 2018 5:19 pm
by Sean Reyes 1J
You would be correct in saying that.
Because there will always be a difference in electronegativity/electron affinity,the cation in the ionic bond will exert an electrostatic attraction on the electron surrounding the anion.
This would distort the electron cloud, implying the concept of polarization.
Specifically, the size of the anion causes an increase in the covalent character, as the electron cloud surrounding a larger anion becomes much more easily polarizable.
This whole idea ties into the concept of sharing electrons rather than transferring them to create ionic bonds, which is why ionic bonds will always (to a degree) have some covalent character.
I hope this makes sense I'm literally a mess.

Re: "ionic character"

Posted: Sat Nov 03, 2018 8:19 pm
by Arlene Linares 3A
hazelyang3E wrote:Yes! I believe that your assumptions would be correct based on what Professor Lavelle taught in lecture. He introduced the concepts of correcting BOTH the covalent and iconic models. For covalent models, he discussed the fact that electron pairs in covalent bonds may not be equally shared all the time. For ionic models, he discussed how all ionic bonds have at least some degree of ionic character, and then went into greater detail about ions that are highly polarizable which result in ionic bond with more covalent character versus ions with high polarizing power which cause large distortions in the ionic bond. Hopefully this helps to clarify/confirm your thoughts!



Thank you for the information :)