Just now, we are having the semicentenary of the discovery of the element 43, later on named “technetium” (1,2). In 1937, Perrier and Segre showed that radioactive isotopes of element 43 could be formed by neutron or deuteron bombardment of molybdenum. They investigated the activity in order to collect some information on the chemistry of 43. By the introduction of technetium-99m into nuclear medicine in the early sixties the chemistry of technetium, especially its coordination chemistry, has been promoted into new spotlight.