  We fabricate artificial molecules composed of heavy atom lead on a van der
Waals crystal. Pb atoms templated on a honeycomb charge-order superstructure of
IrTe2 form clusters ranging from dimers to heptamers including benzene-shaped
ring hexamers. Tunneling spectroscopy and electronic structure calculations
reveal the formation of unusual relativistic molecular orbitals within the
clusters. The spin-orbit coupling is essential both in forming such Dirac
electronic states and stabilizing the artificial molecules by reducing the
adatom-substrate interaction. Lead atoms are found to be ideally suited for a
maximized relativistic effect. This work initiates the use of novel two
dimensional orderings to guide the fabrication of artificial molecules of
unprecedented properties.
