Highly reflective radioactive metal. m.p. 2172 ºC; 3942 ºF b.p. 4877 ºC; 8811 ºF density 11.50 g/cc; 717.92 pound/cubic foot	memory peg
	1937 Emilio G. Segrè & Carlo Perrier, Italy
	τεχνητος (technètos) = artificial (Greek)

In Mendeleyev’s Periodical Table, this group was completed by the then undiscovered eka-manganese (no. 43) and dvi-manganese (no. 75).

As early as 1877 the Russian chemist Serge Kern described his discovery of a new metal, which he named Davyum, named after the famous English chemist Sir Humphry Davy (note). He placed the metal between Molybdenum (42) and Ruthenium (44). In 1881 was written about this discovery: "Concerning Davyum, which was announced in 1877 by Sergius Kern as a new element belonging to the platinum group, Mr. Humpidge expresses the opinion that the investigator failed to take the necessary precautions to eliminate the platinum metals and iron; or, at least, that he fails to state how he did so. He holds, on this account, that the existence of this alleged new element has not been satisfactorily proven, and that the discovery may therefore for the present be ignored" (note)

In 1896 followed again a discovery of element 43, this time named Lucium (note). I have not found any further information.

In 1908 a rare mineral, thorianite, found in the gem-gravels of Ceylon, was examined for new elements. The Japanese chemist Masataka Ogawa found indications of three new species: one which he called Nipponium, assigned as element 43; the second with an equivalent of about 16’ 7; whilst the third yielded a radio-active oxide (note) . From the modern chemical viewpoint Nipponium has to be considered to be the element 75 (Rhenium).

In 1925 Walter Noddack, Ida Tacke (later Mrs. Noddack) and Otto Berg discovered element 75 in a sample of gadolinite (a basic silicate of beryllium, iron and lanthanides) and named it Rhenium. The Noddacks also claimed to have detected element 43 and named it Masurium after Masuria in Eastern Prussia, the region where Walter Noddack's family originated. This claim was not confirmed.

Technetium is actually detected in 1937. In the summer of 1936 Emilio G. Segrè (1905-1989), professor of physics at Palermo (Sicily, Italy), visited Berkeley, and saw the new cyclotron laboratory. He became acquainted with Ernest Lawrence and his collaborators McMillan, Abelson, Cooksey, and others. Segrè returned to Palermo with a scrap of radioactive Molybdenum given to him by Lawrence from the Berkeley 27" cyclotron. Together with the professor of mineralogy, Carlo Perrier (1886-1948), he carried out a number of radiochemical experiments on the scrap, which eventuated in the discovery of element No. 43 (Technetium).

Friedrich A. Paneth (1887-1958) suggested in 1947 that the first producer of an artificial element was entitled to name the element. The University of Palermo, that hosted the discoverers, tried to force them to named element #43 Panormium (after Panormus, the latin name for Palermo), but after the failure of Florentium (see Promethium) Segrè and Perrier preferred a less stressful name, besides they were not from Palermo, but from the north of Italy (note). Finally, they suggested the name Technetium after the Greek τεχνητος [technètos] = artificial. Technetium was the first element artificially produced.

John and Gordon Marks suggested in 1994 the name Danubium (Da), the other northern boundary of the Roman empire, but the Danube is divided by many cataracts and rapids, reflecting danubium's radioactivity (note). The Marks brothers found the old names ugly and confusing. They offered alternative names that are equivalent contemporary (at the time and place of discovery) metaphors, both more euphonious and more memorable. John Marks explains this choice: "... it had been discovered by Noddack, Tacke and Berg in 1925 but they called it Masurium, Ma, after a WWI battle in Prussia. Naturally this name didn't go down too well with the losing side... They would have been much better to call it danubium, Da, after the Danube, just as they called the next element [which they also discovered] in group VIId rhenium, Re, after the Rhine" (note).

The Disputed Discovery of Element #43 (Technetium)
Summary of a paper in the Sigma Xi Colloquium Series, Research Triangle Park, NC, 27 January 2000,
by John T. Armstrong, Surface and Microanalysis Division, National Institute of Standards and Technology (NIST), and P.H.M. Van Assche, Physics Dept., KULeuven, Belgium.

In 1925, Noddack, Tacke and Berg reported discovery of element Z=43, which they named Masurium, based on line identification of x-ray emission spectra from chemically concentrated residues of various U-rich minerals. Their results were disputed and eventually the discovery of element 43 (Technetium) was generally credited to Perrier and Segre, based on their chemical separation of neutron-irradiated molybdenum in 1937. Using first principles x-ray emission spectral generation algorithms from the N.I.S.T. DTSA spectral processing program, we have simulated the x-ray spectra that would be expected using their likely analytical conditions (from their papers and contemporaneous reports) and the likely residue compositions suggested by Noddack et al. and Van Assche. The resulting spectra are in close agreement with that reported by Noddack et al., place limits on the possible residue compositions, and are supportive of the presence of detectable amounts of element 43 in their sample. Moreover, the calculated mass of element 43 shown in their spectrum is consistent with the amount that would be now expected from the spontaneous fission of U present in the ores they studied. The history of the original masurium/technetium controversy and the means used to reexamine the original record will be presented in this scientific detective story.