  The ExoMol database (www.exomol.com) provides extensive line lists of
molecular transitions which are valid over extended temperatures ranges. The
status of the current release of the database is reviewed and a new data
structure is specified. This structure augments the provision of energy levels
(and hence transition frequencies) and Einstein $A$ coefficients with other key
properties, including lifetimes of individual states, temperature-dependent
cooling functions, Land\'e $g$-factors, partition functions, cross sections,
$k$-coefficients and transition dipoles with phase relations. Particular
attention is paid to the treatment of pressure broadening parameters. The new
data structure includes a definition file which provides the necessary
information for utilities accessing ExoMol through its application programming
interface (API). Prospects for the inclusion of new species into the database
are discussed.
