Element number 43, now called technetium, has had a curious history. As a hypothetical element, when the implications of the periodic table were first realized, it was called eka-manganese after its chemical homologue. In 1925 three German chemists announced its detection by means of lines in the X-ray spectrum, and gave it the name masurium; but their discovery has not been confirmed and is now considered erroneous, although their parallel discovery of rhenium, element number 75, was valid.