Chemical formula nomenclature question

10/24/08

In chemical formulas on this site what does the " | " character signify? For example for Mottramite the formula listed is Pb(Cu,Zn)[OH|VO4] . What is the difference between the comma given in the (Cu,Zn) portion of the equation vs. the "|" given in the [OH|VO4] portion of the equation?

Best regards,
Gordon

Hi! Its just a way to separate the anions and to more clearly show which are the anion groups. Many people doesn't prefer using it. Also in my opinion this makes unnecessary complication. (Cu,Zn)(VO4)(OH) looks better for me. Some people would even prefer (Cu,Zn)VO4(OH) one.

Regards!

Ahh... Thank you. I prefer the (VO4)(OH) also. I'm used to reading "|" from the c programming language as "or".

Thanks again.
Gordon

"Some people would even prefer (Cu,Zn)VO4(OH) one."

This remains ambiguous, because vanadium can form part of both cations and anions. To stay safe, (VO4) has to be preferred

And Pb(Cu,Zn)[VO₄](OH) is better of all.

In these cases it is really a personal attempt to understand the structure better. However, in strict chemical nomenclature rules one would never use "I" or even [ ] 's.

In strict chemical nomenclature, the square brackets are used often: complexes, repeating units in polymers, to indicate intermediates in a mechanistic reaction sequence, to denominate clusters (i.e. mass spectrometry), to name just a few.

Yes Peter you are correct about the square bracket but we were speaking about mineral chemical formula and not complexes or polymers. That's why I did not bother mentioning them.