Quasi-1D Cations 1(infinity)[Ni8Bi8S]^n+ of Variable Charge: Infinite Columns 1(infinity)[Ni8Bi8S]^2+ in the Novel Compound Ni8Bi8SI2

The new compound Ni8Bi8SI2 has been synthesized and its crystal structure determined by X-ray crystallography. The structure contains onedimensional (1D) cations 1[Ni8Bi8S]^2+ separated by iodine anions. The geometry of the columns is similar to that of the recently reported 1[Ni8Bi8S]+, and the main difference between them is only their formal charge. Electronic structure calculations and physical properties measurements were performed to analyze the influence of the number of valence electrons on the bonding and properties of compounds containing these 1D cations. It was shown that the removal of one electron (i.e., 1[Ni8Bi8S]+(right arrow) 1 [Ni8Bi8S]^2+) mainly affects the Ni-S bonding within the cation and essentially has no influence on the intermetallic Ni-Bi bonding. It was found that Ni8Bi8SI2 containing double-charged columns has conductivity properties more similar to a pure 1D metal than the congener Ni8Bi8SI containing mono-charged columns.