phosphate glass is fluorophosphate glass. [48] [49] [ edit ] Chalcogenides The  chalcogens —the elements in  group 16  of the  periodic table —particularly  sulfur  (S), selenium  (Se) and  tellurium  (Te)—react with more  electropositive  elements, such as  silver , to form chalcogenides. These are extremely versatile compounds, in that they can be