KnowraFranciumLinked fromLinked fromThe 6 pages that link to Francium, each with the reason it gives.All 6Broader topic 3Related 1Compared with 2RubidiumCompared with: Francium lies below rubidium in Group 1 but is too scarce and unstable for practical use.CaesiumCompared with: Francium lies below caesium in Group 1 but is too rare and unstable for practical clocks.