Explanatory notes
… Th 90 Radioactive element (28.44). Thulium............. Tm 69 Rare‑earth metal (28.05). Tin...................... Sn … from the mother‑liquors of natural sodium nitrates by treatment with sulphur dioxide or sodium hydrogen sulphite, or … from marine algae by drying, incinerating and chemical treatment of the ash. It is a very dense solid (specific gravity …
