HypDH

Determination of stability constants and formation enthalpies from calorimetric data

This program enables the calculation of

• either formation enthalpies using previously determined stability constants
• or formation enthalpies and stability constants

in systems where one or more complexes are in equilibrium in solution with a set of reagents. It is a Windows application. Key features are as follows

• There are no restrictions on the number of reagents or equilibria
• Typically HypDH uses calorimetric titration data; multiple titration curves can be treated simultaneously
• Data import may be from a file containing titre, corrected heat^* data pairs
• Batch data may also be used
• Data is imported from ASCII files containing titration volume, corrected heat data pairs
• Heats may be expressed in Joules or calories
• Stability constants may be fixed at "known" values, or refined
• Formation enththalpies may be fixed at "known" values, or refined
• Data may be fitted interactively on-screen before refinement
• Refinement is by a stabilised non-linear least-squares method with Jacobian calculated by means of analytical formulae
• Reaction entropy may be calculated

^* Corrected heat is the heat developed in a titration step, corrected for all non-chemical effects such as heat of dilution, calorimeter effects etc.

This example shows a system with three reagents and eight complexes Stability constants and reaction enthalpies for all complexes except ML, MLH and M₂L (M = MeHg⁺, L = gly^-) have been determined in separate experiments. The formation enthalpies are "live", that is, they change with every change of stability constant.

Stability Constants home page