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1947, in the meaning defined above
Greek astatos unsteady, from a- + statos standing, from histanai to cause to stand — more at stand
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“Astatine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/astatine. Accessed 29 May. 2020.
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— called also ekaiodine
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Britannica.com: Encyclopedia article about astatine
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