The reaction between perfluoroalkyl iodides with a threefold excess of a 1:1 M mixt. of Se and Cu is a new method for the prepn. of corresponding monoselenides and diselenides. They are oxidized with HOF without a solvent to bis(perfluoroalkyl) selenium(IV) oxides. Halogenation of (Rf)2Te with XeF2, Cl2 or Br2 yielded (Rf)2TeF2, (Rf)2TeCl2 and (Rf')2TeBr2. Oxidn. of (C2F5)2Te with conc. HNO3 gave (C2F5)2Te(OH)NO3. When (CF3)2TeCl2 is treated with AgNSO metathesis took place forming (CF3)2Te(NSO)2. Two (C6F5)2Te(VI) derivs. with the general formula (C6F5)2TeX4 with X = CF3C(O)O and F are prepd. from (C6F5)2TeO2 and CF3C(O)OH or SF4, resp. The monotelluride (n-C6F13)2Te was synthesized similarly from n-C6F13I, Te and Cu. X-ray structures for (n-C4F9)2SeO, (n-C3F7)2TeCl2, and [(CF3)CF]2TeCl2 are provided.