  The crystal structure of solid-state materials with unique lattices is
considered one of the main factors determining physical properties, including
superconductivity. Materials with honeycomb lattices have inspired intense
research interest for their novel properties. A previously unknown compound,
Ta4CoSi, are discussed herein and its crystal structure and superconducting
properties. It crystallizes in a CuAl2-type structure (space group P4/mcm, No.
124) with the lattice parameters a = b = 6.17755(7){\AA} and c = 4.98443(8)
{\AA}, featuring honeycomb networks of Ta-Ta in (110) plane. Superconductivity
is observed below the critical temperature of 2.45 K, while lower and upper
critical magnetic fields are 9.86 mT and 0.84 T, respectively. Experiments and
theoretical calculations show that the honeycomb lattices significantly
influence the superconducting properties. This material may thus provide a new
platform for investigating the exotic superconductivity of honeycomb networks.
