Re: copper oxide

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Mddeming-at-aol-dot-com>

In a message dated 2/6/02 7:47:56 PM Eastern Standard Time, tesla-at-pupman-dot-com
writes:



>
> He didn't say he wants copper oxide, he wanted to know
> why he wasn't getting it. At least one form of Copper
> Oxide -is- green. 




Copper Oxide is black(CuO) or red (Cu2O), not green. It is the hydrated
chloride of copper that is green (CuCl2.2H20). This is why salt water and sweat
leave greenish deposits. This should not be confused with the green flame
produced when copper is oxidezed at a high temperature. If you are sure you've
seen green copper oxide, publish it. The editors of the "Handbook of Chemistry
and Physics 77th ed." are unaware of it. About 25 years ago, there was some
talk of a copper suboxide (Cu4O) but its existence was never verified.

The only form of copper I've seen

>
> turn black was brass when Liver of Sulfur was applied,
> and in that case it may be the zinc 



Copper sulfide is also black. The black oxide of copper forms when copper is
oxidized in an oxygen poor atmosphere, otherwise the red oxide forms. 

(is there tin in

>
> brass?) turning black.


Brass is copper and zinc. Bronze is copper and tin, occasionally with other
trace elements.

Extremely fine-grained, unoxidized copper crystals do have a pinkish cast to
them which is probably what he saw.

Matt D.