Thermaldynamically or kinetically stable?

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Discussion Overview

The discussion revolves around the concepts of thermodynamic and kinetic stability, particularly in relation to specific compounds like dihydrogen phosphites. Participants explore methods for obtaining necessary thermodynamic data, such as enthalpy and entropy, when such information is not readily available.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions how to evaluate thermodynamic and kinetic stability when enthalpy and entropy data are unavailable for certain compounds.
  • Another participant suggests that experiments and simulations are two potential methods for obtaining detailed energy and entropy information about new compounds.
  • A later reply specifies the compounds of interest, dihydrogen phosphites, and notes the lack of available thermodynamic data in physical chemistry handbooks.
  • One participant provides references to specific thermochemical properties of related compounds, including enthalpy and entropy values for potassium dihydrogen phosphate and ammonium dihydrogen phosphate.

Areas of Agreement / Disagreement

Participants express a shared concern about the difficulty of obtaining thermodynamic data for specific compounds, but there is no consensus on the best approach to resolve this issue.

Contextual Notes

The discussion highlights limitations in available data for specific compounds and the reliance on external resources for thermodynamic properties.

solidacid
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hi
I have a question about thermodynamic and kinetic stabiliy. for the general materials we can calculate the free energy and k for evaluation of thermaldynamical and kinetical stabiliy. however, for some strange compond, it is impossible to find the enthalpy and entropy to calculate the fre energy.

so could someone give me a advice to solve this problem?

thank you
!
 
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Can you be more specific, if you're talking about a certain compound? Maybe someone here has experience working in that area.

There are two ways to get detailed energy and entropy information about a new compound: perform experiments and run simulations.
 
Mapes said:
Can you be more specific, if you're talking about a certain compound? Maybe someone here has experience working in that area.

There are two ways to get detailed energy and entropy information about a new compound: perform experiments and run simulations.

Thanks a lot.
my material is dihydrogen phosphites e.g. NH4H2PO3 and KH2PO3. Phosphites are widely used as furtilizers, so few people are interested to their thermo properties. Even I checked several physical chemistry handbooks while no useful information was found. :(

could you give me more detials how to get the entropy or free energy information?
 
Try Barin's Thermochemical properties of inorganic substances (H=-1568 kJ/mol, S=134.9 J/mol-K for potassium dihydogen phosphate) and Lange's Handbook of Chemistry (H=-1445 kJ/mol, S=152.0 J/mol-K for ammonium dihydogen phosphate).
 

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