Swiss chemist · 1817–1894
Jean Charles Galissard de Marignac
Jean Charles Galissard de Marignac discovered ytterbium in 1878 and gadolinium in 1880, and his precise atomic weight measurements were among the best of the 19th century.
- Elements credited
- 2
- Discoveries
- 1878–1880
- Co-discoverers
- 0
- Where
- Switzerland
The work
In 1878 Marignac heated erbium nitrate until it decomposed and extracted the residue with water. Part of it was a new, colourless earth he named ytterbia, after Ytterby, the Swedish village whose quarry had already given its name to yttrium, erbium and terbium.
In 1880 he detected another new earth in samarskite. It was named gadolinium in honour of Johan Gadolin, who had analysed the first rare-earth mineral almost a century earlier.
Ytterbium and Gadolinium side by side
| Property | Ytterbium | Gadolinium |
|---|---|---|
| Discovered | 1878 | 1880 |
| Atomic number | 70 | 64 |
| Category | Lanthanide | Lanthanide |
| State at room temperature | Solid | Solid |
| Melting point | 819 °C | 1,313 °C |
| Density | 6.9 g/cm³ | 7.9 g/cm³ |
Life and career
Marignac was born in Geneva and trained as an engineer at the École Polytechnique in Paris. He worked briefly with Justus von Liebig in Germany and at the Sèvres porcelain factory before becoming professor of chemistry at the University of Geneva.
He measured atomic weights with exceptional care, and his results were used to test Prout’s hypothesis that atomic weights are whole-number multiples of hydrogen’s.