NAME¶chemeq - Chemical Equation Parser and Renderer
chemeq [-M] [-m] [-l] [-c] [-w] [-C] [-e] [-s] [-n] [-W]
chemeq [-h] [-v]
DESCRIPTION¶chemeq is a chemical equation analyzer. It is a fast lexical and syntaxic analyser which helps to find out chemical information embedded in source chemical equations. Data can be output in various sophisticated formats, depending on options. 'chemeq' defaults to 'chemeq -mlcwCn'.
EXAMPLES¶echo "1/2 Cu^2+ + OH- -> 1/2Cu(OH)2s" | chemeq
echo "MnO4^- + 8H3O^+ + 5e- --> Mn^2+ + 12 H2O" | chemeq
echo "MnO4^- + 8H3O^+ + 5e- --> Mn^2+ + 12 H2O" | chemeq -w
echo "MnO4^- + 8H3O^+ + 5e- --> Mn^2+ + 8 H2O" | chemeq -c
NOTES¶syntax of ions
Composing chemical equations
echo "MnO4^- + 8H3O^+ + 5e- --> Mn^2+ + 8 H2O ~ 5Fe^3+ + 5e- -> 5Fe^2+" | chemeq
will display the pure redox equation from the first equation, minus the second one. Electrons are simplified. So it will be equivalent to:
echo "MnO4^- + 8H3O^+ + 5Fe^2+--> Mn^2+ + 8 H2O + 5Fe^3+" | chemeq which is their combination.
Mutiplying a chemical equation by one coefficient
echo "5 * Fe^3+ + e- -> Fe^2+" | chemeq
will be equivalent to
echo "5Fe^3+ + 5e- -> 5Fe^2+" | chemeq
Combining chemical equations, with coefficients
echo "Fe^3+ + e^- -> Fe^2+ (0.77 V) # Fe^2+ + 6CN^- -> Fe(CN)6^4- (Kfa=1e24) ~ Fe^3+ + 6CN^- -> Fe(CN)6^3- (Kfb=1e31)" | chemeq
which will work as expected, and yield a good value for the stan‐ dard potential of the redox couple of hexacyanoferrate II and III ions.
KNOWN BUGS¶When not specified, chemical entities coming from the standard input are believed to be in aqueous solutions. Water is considered by default as the main solvent. Only one liquid (aqueous) phase is currently taken in account. All solid chemical entities are considered as parts of separated phases. Suffixes _s, _g and _aq can be used to enforce the type of some chemical entities. There may be problemes when you write a standard potential with no decimal dot. For example, the entry Mn^2+ + 2e^- -> Mn_s (-1 V) would trigger an error. Then write Mn^2+ + 2e^- -> Mn_s (-1.0 V) or the more accurate value Mn^2+ + 2e^- -> Mn_s (-1.18 V) and there will be no error.
AUTHOR¶Georges Khaznadar <email@example.com>
COPYRIGHT¶Copyright © 2000-2013 Georges Khaznadar
Redistribution and use of this manpage in source and binary forms, with or without modification, are permitted under the terms of the GNU General Public Licenses, version 2
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