I am checking the Oxygen Balance calculation as reported in Wikipedia (https://en.wikipedia.org/wiki/Oxygen_balance).
Some calculated values corresponds to those reported in that page (e.g. nitromethane (-39%) and trinitrotoluene (−74%), ammonium nitrate (+20%)).
While some of the values reported in the wiki page do not fit with the formula (e.g. ammonium perchlorate (wiki +34%, calculated 27%), potassium chlorate (wiki +39.2%, calculated 26%, sodium chlorate (wiki +45%, calculated 30%)).
Oxygen Balance is used to evaluate explosivity of a substance and it is also cited by ECHA in ECHA Guidance on the Application of the CLP Criteria Version 6.0 – Jan 2024, page 93.
Am I doing something wrong or am I missing something?
Oxygen balance is often calculated to CO rather than CO2, maybe a part of the problem originates from this. Usually we use the following formula for CHNOFClS compounds
OxBal=16*(nO+nF/2+nCl/2-(2*nC+0.5*nH+2*nS))/MW*100
Note, however, that the oxygen balance cannot be used as a measure of explosibility or energetic potential, it is much more complicated. For benchmarked emripical equations for energetic potential see our paper Article Progress and Performance of Energetic Materials: Open Datase...
we also suggested a rough estimation for the mechanical sensitivity of compound here Article Sensitivity of Energetic Materials: Evidence of Thermodynami...
Hope that helps,
Nikita Muravyev
Thank you Nikita V Muravyev for your answer. Do you have a reference for the formula you usually use to evaluate the oxygen balance?
The wiki formula also includes the number of metal atoms. Is it something that you consider?
Thank you,
Andrea
For example, i've added two screenshots
1) from https://www.wiley.com/en-us/Explosives+Engineering-p-9781119537175
2) from Book Propellants and Explosives: Thermochemical Aspects of Combustion
Yes, if you have the metal in composition, the consumption of the oxygen to form oxides should be considered.