Decipium was the proposed name for a new chemical element isolated by Marc Delafontaine from the mineral samarskite. He published his discovery in 1878 and later published a follow-up paper in 1881.123
Decipium was considered to be in the cerium group of rare earths.4
In 1880, spectral analysis proved that decipium had a high samarium content. It is now believed that Delafontaine's decipium sample was a mixture of samarium with traces of other rare earth elements.5
References
References
- Delafontaine, Marc (1878). "Sur le décepium, métal nouveau de la samarskite". Journal de pharmacie et de chimie. 28: 540.
- Delafontaine, Marc (1881). "Sur le décipium et le samarium". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 93: 63.
- Delafontaine, Marc (1878). "Sur le décepium, métal nouveau de la samarskite". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 87: 632.
- Harmsworth's Universal Encyclopaedia vol X, 1922 p6493 Rare Earths.
- Marco Fontani; Mariagrazia Costa; Mary Virginia Orna (13 October 2014). The Lost Elements: The Periodic Table's Shadow Side. Oxford University Press. pp. 122–123. ISBN 978-0-19-938334-4.