From AgTeO2F and Ag2(TeO2F2) to Ag3F3(TeF6)(TeO2)12: the first silver tellurite oxyfluorides with linear and nonlinear optical properties

AgTeO 2 F and Ag 2 (TeO 2 F 2 ) are the first silver fluorotellurites, while Ag 3 F 3 (TeF 6 )(TeO 2 ) 12 is the first silver fluoride tellurite. Ag 3 F 3 (TeF 6 )(TeO 2 ) 12 features an NCS mixed valence Te oxyfluoride with an SHG intensity of about 70% that of commercial KDP.