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chemeq - Chemical Equation Parser and Renderer
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Copyright
Copyright © 2000-2013 Georges Khaznadar
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chemeq 2.10 07/11/2023 CHEMEQ(1)
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'.
Environment
chemeq_input
if set, this variables's value overrides the standard input. If this variable is not set, the
variable w_chemeq_input is taken in account (useful for the WIMS server).
w_chemeq_input
See above (useful for the WIMS server).
chemeq_option
if set, this variable's value overrides the options.If this variable is not set, the variable
w_chemeq_option is taken in account (useful for the WIMS server).
w_chemeq_option
See above (useful for the WIMS server).
Examples
echo"1/2Cu^2++OH-->1/2Cu(OH)2s"|chemeq
will display information about the reaction of hydroxyde and Cu II ions.
echo"MnO4^-+8H3O^++5e--->Mn^2++12H2O"|chemeq
will display information about the reaction of reduction of permanganate ions in an acid environment.
echo"MnO4^-+8H3O^++5e--->Mn^2++12H2O"|chemeq-w
will display the LaTeX format for the Nernst law related to the reduction of permanganate ions in an
acid environment.
echo"MnO4^-+8H3O^++5e--->Mn^2++8H2O"|chemeq-c
will highlight the lack of conservation of elements H and O (water molecules are not well balanced).
echo"func:html_table"|chemeq
Outputs an HTML Element, featuring a periodic table of chemical elements, which contains the exact
data used by chemeq itself for the molar masses.
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(-1V) would trigger an error. Then write Mn^2++2e^-->Mn_s(-1.0V) or the more accurate value Mn^2++2e^-->Mn_s(-1.18V) and there will be no error.
Name
chemeq - Chemical Equation Parser and Renderer
Notes
syntaxofions
although in some cases, shorter expressions are successfully parsed, it is safer to consider that an
"up arrow" (^) must be put before the charge symbols of an ion. Examples : H3O^+, Fe(CN)6^4-, OH^-
Composingchemicalequations
Two operators are defined, # as an additive oprator and ~ (tilde) as a substractive operator: they
allow one to compose several chemical equations
echo"MnO4^-+8H3O^++5e--->Mn^2++8H2O~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++8H2O+5Fe^3+"|chemeq which is their combination.
Mutiplyingachemicalequationbyonecoefficient
The operator * permits one to multiply a whole equation by one coefficient which may be a fraction.
Here is an example:
echo"5*Fe^3++e-->Fe^2+"|chemeq
will be equivalent to
echo"5Fe^3++5e-->5Fe^2+"|chemeqCombiningchemicalequations,withcoefficients
The two previous techniques can be used at the same time, which enables you to make more comlicated
combinations, like this one:
echo"Fe^3++e^-->Fe^2+(0.77V)#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.
Options
-M
Outputs al list of space separated molecular weights.
-m
Outputs a minimal output. It allows chemeq to be idempotent, i.e. the command 'chemeq | chemeq' is
equivalent to 'chemeq'.
-l
Outputs a LaTeX string representing the chemical equation.
-c
Outputs a message giving information about the Conservation of elements and charges in the equation.
'OK' means that both elements and electric charges are balanced.
-w
Outputs the LaTeX string representing the Gulder-Waage equation related to the input chemical
equation, or the Nernst equation, if the input equation is a redox semi-equation.
-C
Outputs a detailed Count of the molecules and atoms contained in each member of the chemical
equation. For example for the equation "H2_g + 1/2 O2_g --> H2O" it outputs: "H2_g|H:1*2, 1/2
O2_g|O:1/2*2; H2O|H:1*2 O:1*1"
-e
Outputs a detailed count of the Electrical charges.
-s
Outputs a list of the chemical Species.
-S
Outputs a list of the chemical *S*tœchiometric coefficients.
-n
Outputs a Normalized string accounting for the input equation. Two chemical equations having the same
normalized string are chemically equivalent, even if the molecules are scrambled around and the
coefficient are not equal but proportionnal.
-W
Changes the behavior of the renderer for some versions of Wims : works around a bug with the macro
\rightarrow.
-h
Displays Help.
-v
Displays the Version number
Synopsis
chemeq [-M] [-m] [-l] [-c] [-w] [-C] [-e] [-s] [-S] [-n] [-W]
chemeq [-h] [-v]
PNG Icons
