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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: DazzaC on June 09, 2010, 07:33:31 AM

Title: Electrical Conductivity of Hydroxides
Post by: DazzaC on June 09, 2010, 07:33:31 AM
Hi Everyone, (Be nice it's my first post :p)

I know for a fact that all oxides are good insulators, hence are bad at conducting electricity. But what about hydroxides? Does the addition of the hydrogen change anything?

If anyone can answer this, regarding specifically; Zinc Hydroxide. The hydroxide is formed from a reaction of Zinc Oxide and Water, and I know that water (with impurities) is a good conductor. So I'm puzzled at the moment.

Thanks :).

EDIT: Oh, and Borek (If you get around to reading this) - I'm the same guy from PhysicsForums. I just found this forums not too long ago.
Title: Re: Electrical Conductivity of Hydroxides
Post by: DazzaC on June 10, 2010, 01:18:38 AM
Anybody? :(
Title: Re: Electrical Conductivity of Hydroxides
Post by: cliverlong on June 10, 2010, 02:56:12 AM
My idea. On a simplistic level (I don't know a sophisticated explanation) for a material to be an electrical conductor it must possess a mobile charge carrier. This can be:

Electrons - in a material with a metal-like structure
Ions in aqueous solution of an ionic solid
Ions in a molten ionic solid
Ions in a gas plasma

Metal oxides, metal hydroxides, metal sulphates etc are all ionic solids and have no free charge carriers therefore are insulators.

Clive
Title: Re: Electrical Conductivity of Hydroxides
Post by: DazzaC on June 10, 2010, 07:06:19 AM
Great, thanks - that's all I really needed to know :)
Title: Re: Electrical Conductivity of Hydroxides
Post by: tamim83 on June 10, 2010, 04:54:12 PM
Quote
Metal oxides, metal hydroxides, metal sulphates etc are all ionic solids and have no free charge carriers therefore are insulators.

Yes if they are solids.  Things may change when these compounds are molten.  When we are talking solutions, I guess it depends on the solubility of the ionic compound in water.  This is going to change depending on the identity of the metal in the hydroxide or oxide. 



Title: Re: Electrical Conductivity of Hydroxides
Post by: cliverlong on June 11, 2010, 02:43:21 AM
Quote from: tamim83 on June 10, 2010, 04:54:12 PM
Quote
Metal oxides, metal hydroxides, metal sulphates etc are all ionic solids and have no free charge carriers therefore are insulators.

Yes if they are solids.  Things may change when these compounds are molten. 
That point is made in my answer.
Quote

When we are talking solutions, I guess it depends on the solubility of the ionic compound in water. 
Good point
Quote
This is going to change depending on the identity of the metal in the hydroxide or oxide. 
If you mean the solubility of an ionic solid depends on which metal and anion are in the ionic solid, then yes.

Title: Re: Electrical Conductivity of Hydroxides
Post by: FreeTheBee on June 23, 2010, 03:53:10 PM
Not all oxides are insulators. For example ReO3 and IrO2 conduct fine. And think of the mixed oxide ITO (indium tin oxide), which is used a lot for transparent electrodes.
Title: Re: Electrical Conductivity of Hydroxides
Post by: cliverlong on June 23, 2010, 04:04:21 PM
Quote from: FreeTheBee on June 23, 2010, 03:53:10 PM
Not all oxides are insulators. For example ReO3 and IrO2 conduct fine. And think of the mixed oxide ITO (indium tin oxide), which is used a lot for transparent electrodes.
Interesting answer.
It appears chemistry always throws up exceptions.
Out of interest what are the charge carriers in ReO3 and IrO2 ?

Clive