BONDING AND ELECTRONIC-PROPERTIES OF CS3TE22

The compound Cs3Te22 is well-known for its interesting structural feat ures. It contains both a unique 2,3-connected defect square Te sheet a nd Te-8 rings. For a better understanding of the structure and bonding , the band structure of Cs3Te22 is examined by means of the ab initio tight-binding linear muffin-tin orbital (TB-LMTO) method, which is bas ed upon density functional theory (DFT). The calculations are compleme nted by an analysis of the electronic density topology with the electr on localization function (ELF) and a traditional orbital analysis usin g the projected density of states (DOS) and the crystal orbital Hamilt onian population (COHP). Our study indicates that the short Te-Te cont acts between Te-8 rings and the defect Te-6(3-) sheet in this compound have a direct influence upon the properties of this material. The pre sence of this interaction perturbs the electronic density relative to that which one obtains from analysis of the isolated defect sheet and leads to favorable conditions for an insulator state.