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Please help!



Dear Sir,

I have noticed something interesting whilst using PHREEQC for copper
speciation modeling.  I have noticed that the llnl.dat database has
provided different stability constants for the various copper acetate
complexes to the Minteq database (please see the table below):


			Cu		Acetate		Log_k
			
llnl.dat		1		1			2.525
			1		2			5.882
			1		3			9.379
			1		4			  -

Minteq.dat		1		1			2.22
			1		2			3.63
			1		3			3.1
			1		4			2.9

The constants shown above, especially the ones displayed in llnl.dat, are
significantly higher than the literature values.  Since the quality of the
speciation model predictions is solely dependant on the stability constants
used, the discrepancies between the logK values may result in confusion and
inaccurate predictions of the speicies distribution.  Could you please
comment on the situation and could you please also tell me what the sources
of the constants listed in llnl.dat and Minteq.dat are?  

Thanks in advance for your help!

Yours sincerely,
Zhi Ling ZENG 




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