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Coordination number

Posted: Sun Jun 10, 2018 3:53 pm
by Priscilla Okaiteye
Can someone just briefly explain to me what the coordination number is and how to find it?

Re: Coordination number

Posted: Sun Jun 10, 2018 3:54 pm
by Priscilla Okaiteye
...and maybe also show an example?

Re: Coordination number

Posted: Sun Jun 10, 2018 4:31 pm
by Jocelyn Fermin1J
The number of atoms attached to the central atom, this does not include lone pairs. double bonds and triple bonds only count as 1 for example

SO2 coordination number=2

Re: Coordination number

Posted: Sun Jun 10, 2018 6:13 pm
by Luis Torres 1C
As stated above, the coordination number indicates the number of atoms that surround the central atom. To add to that answer, these 'non-central' atoms are called ligands

Re: Coordination number

Posted: Sun Jun 10, 2018 6:41 pm
by ErinKim1I
Just to add, coordination number typically applies to compounds with a transition metal as the central atom, so it isn't likely that you would encounter a double or triple bond in the first place.

Re: Coordination number

Posted: Sun Jun 10, 2018 8:44 pm
by Anthony Mercado 1K
While I understand that the coordination number denotes the number of ligands attached to a central atom, what importance does this serve to discover any further aspects of the molecule involved?

Re: Coordination number

Posted: Wed Nov 28, 2018 11:00 am
by Jennifer Lathrop 1F
Can the term coordination number apply to all molecules? or only some?

Re: Coordination number

Posted: Wed Nov 28, 2018 11:11 am
by 705137650
the number of atoms or ions immediately surrounding a central atom in a complex or crystal.

Re: Coordination number

Posted: Wed Nov 28, 2018 11:29 am
by Dana Wilks 3I
Jocelyn Fermin1J wrote:The number of atoms attached to the central atom, this does not include lone pairs. double bonds and triple bonds only count as 1 for example

SO2 coordination number=2


Like Jocelyn said, it does not include lone pairs. On a related note, though, the steric number include the number of atoms bonded plus the number of lone pairs on a central atom. This number is useful in VSEPR to determine the electron arrangement.

Re: Coordination number

Posted: Fri Nov 30, 2018 6:11 pm
by Hannah Yates 1K
Jennifer Lathrop 3E wrote:Can the term coordination number apply to all molecules? or only some?


I’m pretty sure a coordination number can only apple to coordination compound, which is the product of a Lewis acid-base reaction in which neutral molecules or anions (called ligands) bond to a central metal atom (or ion) by coordinate covalent bonds.

Re: Coordination number

Posted: Fri Nov 30, 2018 6:46 pm
by Karla_Ocampo 4E
Hi! The coordination number is just the number of atoms attached to the central atom. However as someone stated, don't count lone pairs.