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)