| 1 | With scandium and yttrium, they make up the rare earth metals. | |
| 2 | The development and application of Al-Sc alloy were briefly discussed. | |
| 3 | They turned out to be the undiscovered elements scandium, gallium, technetium and germanium. | |
| 4 | Compounds, inorganic or organic, of rare-earth metals, of yttrium or of scandium or of mixtures of these metals. | |
| 5 | In this paper, an outline of their military and civil potential applications were also presented. |