In this section all breathing gases used are described. (General data of tanks as parts of the equipment are given in the <tank> section within the <equipment> section, while specific tank data — for example pressure at begin and end of dive — are listed with the respective dive (<dive> -> <tankdata>).) For each breathing gas a separate <mix> subsection has to be created. <mix> is the only element within <gasdefinitions> and can be repeated any times needed.
<mix> <name> <aliasname> <o2> <n2> <he> <ar> <h2> <priceperlitre> <maximumpo2> <maximumoperationdepth> <equivalentairdepth> <notes> <para> <link/> (for cross-referencing <audio>, <image>, and <video> objects)