Misidentified chemical elements

superseded scientific theory about combustion

thumb|Didymium glasses

thumb|right|Cat's Eye Nebula (NGC 6543) thumb|Cat's Eye Nebula (NGC 6543) Nebulium was a proposed element found in astronomical observation of a nebula by William Huggins in 1864. The strong green emission lines of the Cat's Eye Nebula, discovered using spectroscopy, led to the postulation that an as yet unknown element was responsible for this emission. In 1927, Ira Sprague Bowen showed that the lines are emitted by doubly ionized oxygen (new style O; old style O), and no new element was necessary to explain them.

right|thumb|A solar eclipse, with the solar corona visible. Coronium was the name of a suggested chemical element, hypothesised in the 19th century. The name, inspired by the solar corona, was given by Gruenwald in 1887. A new atomic thin green line in the solar corona was then considered to be emitted by a new element unlike anything else seen under laboratory conditions. It was later determined to be emitted by iron (Fe13+), so highly ionized that it was at that time impossible to produce in a laboratory.

Austrium is the name of a new chemical element proposed by Eduard Linnemann in 1886. As a chemist at the German University in Prague he experimented with the mineral orthite (from Arendal in Norway). In the course of his works over several years he detected spectral lines at 4165 and 4030 Angstrom, respectively, which he was not able to ascribe to any then known element. These findings were published only after his death after due consideration on May 6, 1886, by the Academy of Sciences of Prague.

Ilmenium was the proposed name for a new element found by the chemist R. Hermann in 1847. During the analysis of the mineral samarskite, he concluded that it does contain an element similar to niobium and tantalum. The similar reactivity of niobium and tantalum complicated preparation of pure samples of the metals and therefore several new elements were proposed, which were later found to be mixtures of niobium and tantalum.