Syntheses, crystal and electronic structures of three new potassium cadmium(II)/zinc(II) tellurides: K2Cd2Te3, K6CdTe4 and K2ZnTe2

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.