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CH3041
STABILITY FIELD
DIAGRAMS
• The stability of an aqueous species or a mineral phase in solution is determined by:
1) the pH of the solution
2) the pE of the solution
3) the activities of
the ions present
4) the value of IAP resulting from the
reaction of the ions
reaction of the ions
5) whether IAP > KSP or IAP < KSP
• A common way of
presenting most of this information
is in stability field diagrams which
relate the presence of a phase to the a range of possible values of pH and pE.
• These diagrams are sometimes plotted with EH vs pH rather than pE vs pH
