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see protactiniumprotactinium
, radioactive chemical element; symbol Pa; at. no. 91; mass number of most stable isotope 231; m.p. greater than 1,600°C;; b.p. 4,026°C;; sp. gr. 15.37 (calculated); valence +4, +5. Protactinium is a malleable, shiny silver-gray radioactive metal.
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at 180 (quoting Anthony Fltzherbert, La Novelle Natura Brevium 94D (1534)) (internal quotation mark omitted).
(69) The Writ of Prohibition was "directed to the ordinaries, and officers, and commissioners of the said court Christian, them commaunding to cease their plee": Natura brevium, 30; see also Gray.
304, 340 (2002) (Scalia, J., dissenting) (quoting 2 ANTHONY FITZHERBERT, NATURA BREVIUM 233B (9th ed.