| Thorium Compounds |
| Thorium dioxide |
Thorium dioxide ThO2 |
| Used to control the grain size of tungsten used for electric lamps. Added to glass, it helps create glasses of a high refractive index and with low dispersion. Consequently, they find application in high-quality lenses for cameras and scientific instruments. |
| Mantles in portable gas lights. These mantles glow with a dazzling light (unrelated to radioactivity) when heated in a gas flame. |