Several new barium copper polychalcogenides were discovered during the last years. Their structures were all unprecedented, displaying a variety of different cationic copper clusters along with dimeric, trimeric, or infinite anionic polychalcogen units. Te
22鈭?/sup> pairs, bent V-shaped Te32鈭?/sup> trimers, linear, hypervalently bonded Se34鈭?/sup> trimers, and infinite, almost linear chains of Te atoms occur in BaCu6鈭?em>xSTe6, BaCu6鈭?em>xSeTe6 and Ba3Cu14鈭?em>xTe12, Ba6.76Cu2.42Te14, Ba2(Cu,Ag)4Se5 and Ba2Cu4鈭?em>xSeyTe5鈭?em>y, respectively.All Cu-based examples exhibit significant copper deficiencies, and are thus p-doped semiconductors or metals. On the other hand, the few isostructural representatives with silver and gold, namely Ba2Ag4Se5 and Ba7Au2Te14, are stoichiometric materials. The Cu deficiencies are deduced to arise from the tendency to mixed-valent compounds.