Recent studies on the nuclear chemistry of technetium.- Technetium in the environment.- The chemistry of technetium nitrido complexes.- Technetium(V) chemistry as relevant to nuclear medicine.- Technetium-99m chelates as radiopharmaceuticals.- High- and low-valency organometallic compounds of technetium and rhenium.- Chemistry of technetium cluster compounds.- Substitution reactions of technetium compounds.- Rhenium complexes labeled with 186,188Re for nuclear medicine.