Promethium(III) oxide
Chemical compound
Promethium(III) oxide is a compound with the formula Pm2O3. It is the most common form of promethium.
01Crystal structure
Promethium oxide exists in three major crystalline forms:
| Form | Pearson symbol | Space group | No. | a; b; c (nm) | β(deg) | Z | Density (g/cm3) |
|---|---|---|---|---|---|---|---|
| Cubic | cI80 | Ia3 | 206 | 1.099 | 16 | 6.85 | |
| Monoclinic | mS30 | C2/m | 12 | 1.422; 0.365; 0.891 | 100.1 | 6 | 7.48 |
| Hexagonal | hP5 | P3m1 | 164 | 0.3802; 0.3802; 0.5954 | 1 | 7.62 |
*a, b and c are lattice parameters, Z is the number of formula units per unit cell, density is calculated from X-ray data.
The low-temperature cubic form converts to the monoclinic structure upon heating to 750-800 °C, and this transition can only be reversed by melting the oxide. The transition from the monoclinic to hexagonal form occurs at 1740 °C.
Sources and credits
This article is adapted from the Wikipedia article “Promethium(III) oxide”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- Pm oxide.jpg by Ralph E. Lapp, Fair use
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