EuSnAs: the first arsenide adopting the NbCrN structure type.

A novel polar intermetallic compound, europium tin arsenide, EuSnAs, was successfully synthesized using a complex multimetal flux reaction. Single-crystal X-ray diffraction reveals that EuSnAs crystallizes in the tetragonal space group P4/nmm [a = 4.35830 (10) and c = 8.9333 (5) Å], adopting the NbCrN structure type. Its layered crystal structure features corrugated Sn sheets separated by [EuAs] slabs. Detailed characterization of the structural relationships between EuSnAs and MoSi2-derived structures are also provided. Density functional theory (DFT) calculations indicate metallic behavior with a pronounced pseudogap at the Fermi level. Crystal Orbital Hamilton Population (COHP) and Crystal Orbital Bond Index (COBI) analyses identify Sn-As and Sn-Sn as dominant covalent contacts, as well as somewhat delocalized bonding within the Sn-bearing layers.