Precipitating CO2 as BaCO3 is a standard method in qualitative analytical
inorganic chemistry.
 
CO2 generated from material(s) to be tested for the presence of carbonate(s)
is bubbled into a clear solution of Ba(OH)2. If CO2 is present in the gas
bubbling through this solution, it will turn milky white and cloudy, and
BaCO3 will eventually precipitate.
 
This test is also a useful in lectures to demonstrate the formation of CO2
during fermentation.
 
 
Wolfram
 
 

-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf
Of Kristine Nielson
Sent: 15 May 2006 22:00
To: [log in to unmask]
Subject: Re: barium carbonate question


Under what conditions does BaCO3 precipitate?  I ask because a while ago I
tried precipitating BaSO4 from gulf of mexico porewaters and had a
coprecipitate with carbon in it (at least, that's what the EA told me), but
everyone I asked claimed BaCO3 shouldn't precipitate at all.  I'm rather
relieved to know the compound at least exists, and would be grateful for any
information on how and where it forms. 
 
Thanks,
 
Kristine