# chemmacros: hydrates according to IUPAC

i have a problem with the output of additon compound according to IUPAC: Compounds like CuSO4*5H2O should not have a space between the dot and the formulae (see IUPAC red book IR-5.6 page 81). How can i do this in a reaction equation?

\documentclass[12pt]{article}
\usepackage[german]{babel}
\usepackage{chemmacros}

\begin{document}

\ch{CuSO4 -> [][5 H20] CuSO4*5H2O}

\end{document}


does not work for equations. for simple formula it is possible to remove the space by using:

\ch{CuSO4}$\cdot$\ch{5H2O}


Is there any possiblity to get the whole thing like IUPAC recommend it?

Thanks a lot

First of all: leave more spaces in the input. The detailed syntax for \ch is described in the chemformula manual. Especially stoichiometric factors and formulas need to be surrounded by spaces (that holds for the optional arguments of the arrows as well) even if they're part of a larger formula like in hydrates. This is shown in section 6.1 of the chemformula manual:

The correct syntax for your example is like this:

\documentclass[12pt]{article}
\usepackage[ngerman]{babel}
\usepackage{chemmacros}

\begin{document}

\ch{CuSO4 ->[ 5 H2O ] CuSO4 * 5 H2O}

\end{document}


If you now want to adjust the space surrounding the dot you can set the option adduct-space to a value that suits you. The IUPAC Red Book indeed both has no spaces surrounding the dot and no spaces between compounds and stoichiometric factors which means both adduct-space and stoich-space need to be set to 0pt for getting the same output:

\documentclass[12pt]{article}
\usepackage[ngerman]{babel}
\usepackage{chemmacros}
\chemsetup{
formula = chemformula ,
chemformula/stoich-space = 0pt
}

\begin{document}

\ch{CuSO4 ->[ 5 H2O ] CuSO4 * 5 H2O}

\end{document}


I am not convinced, though, that the Red Book is making a typographical recommendation here, since the chapter only describes the naming of addition compounds. The Green Book on the other hand has a lot of typographic advice. Although it doesn't explicitly mention it it does use spaces to separate compounds from stoichiometric factors which implies to me that the spaces actually do follow the IUPAC recommendation.

Please also note that you should leave no space between arrows and their arguments. The typeset result of your input clearly shows this:

\ch{CuSO4 -> [][5 H20] CuSO4*5H2O}


• Yes, I know that there should same spaces before and after the stoichiometric factors (like it is written in the manual). But according to IUPAC there should not be spaces between the formula (here: CuSO4), the dot, the stoichiometric factor (here: 5) and the addition compound (here: H2O). – chem-is-try Nov 23 '15 at 14:44
• @chem-is-try have you a source for this? Is this specified somewhere in the Green Book? – cgnieder Nov 23 '15 at 14:46
• yes, see IUPAC red book IR-5.5 page 81. – chem-is-try Nov 23 '15 at 14:47
• The online version only says something about the names of addition compounds. The typeset examples there indeed have no space surrounding the stoichiometric factors, not only within adducts but nowhere (which contradicts the Green Book if this is meant as a typographical recommendation…) – cgnieder Nov 23 '15 at 14:54
• Either way: set both stoich-space and adduct-space to 0pt if you don't want the spaces – cgnieder Nov 23 '15 at 14:56