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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Guillem_dlc on March 24, 2018, 06:03:52 PM

Title: Ionic or covalent?
Post by: Guillem_dlc on March 24, 2018, 06:03:52 PM
Hello,

Is [tеx]PbO_2[/tеx] ionic or covalent? It is being formed by a metal and a non-metal, and then it should be ionic, but in the subject of redox that I am giving me it does not dissociate...

Thanks.
Title: Re: Ionic or covalent?
Post by: Borek on March 24, 2018, 07:40:49 PM
I feel like you are confusing several things at the same time. First of all, it is not like everything ionic is easily soluble and dissociates. Second, just because something is made by reacting metal and non-metal doesn't necessarily mean the compound is ionic, much more important thing is the electronegativity difference. Third, while some oxides are definitely ionic, they never dissociate, at best they react with water. Finally, heavy metal oxides are quite often quite inert.
Title: Re: Ionic or covalent?
Post by: Guillem_dlc on March 25, 2018, 08:09:51 PM
Quote from: Borek on March 24, 2018, 07:40:49 PM
I feel like you are confusing several things at the same time. First of all, it is not like everything ionic is easily soluble and dissociates. Second, just because something is made by reacting metal and non-metal doesn't necessarily mean the compound is ionic, much more important thing is the electronegativity difference. Third, while some oxides are definitely ionic, they never dissociate, at best they react with water. Finally, heavy metal oxides are quite often quite inert.

Thank you very much, I understood what you are saying. But, the compound that I propose is ionic or covalent? For what you give me to understand is ionic ...
Title: Re: Ionic or covalent?
Post by: Borek on March 26, 2018, 10:05:14 AM
The electronegativity difference is 1.6, so technically it qualifies as polar covalent. If you use Linus Pauling formula for calculation of the percentage of the ionic character of the bond you will find it is almost 50/50 ionic/covalent.

Plus - I don't see how the bond character matters in the redox context.
Title: Re: Ionic or covalent?
Post by: Guillem_dlc on March 26, 2018, 02:07:14 PM
Quote from: Borek on March 26, 2018, 10:05:14 AM
The electronegativity difference is 1.6, so technically it qualifies as polar covalent. If you use Linus Pauling formula for calculation of the percentage of the ionic character of the bond you will find it is almost 50/50 ionic/covalent.

Plus - I don't see how the bond character matters in the redox context.

Thank you very much. In the subject of redox we are seeing it when adjusting the reactions, to know if it is necessary to dissociate it or not.