Synthesis, structural characterization, and electronic structure of the novel Zintl phase Ba2ZnP2.

The novel Zintl phase dibarium zinc diphosphide (Ba2ZnP2) was synthesized for the first time. This was accomplished using the Pb flux technique, which allowed for the growth of crystals of adequate size for structural determination via single-crystal X-ray diffraction methods. The Ba2ZnP2 compound was determined to crystallize in a body-centered orthorhombic space group, Ibam (No. 72). Formally, this crystallographic arrangement belongs to the K2SiP2 structure type. Therefore, the structure can be best described as infinite [ZnP2]4- polyanionic chains with divalent Ba2+ cations located between the chains. All valence electrons are partitioned, which conforms to the Zintl-Klemm concept and suggests that Ba2ZnP2 is a valence-precise composition. The electronic band structure of this new compound, computed with the aid of the TB-LMTO-ASA code, shows that Ba2ZnP2 is an intrinsic semiconductor with a band gap of ca 0.6 eV.