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Francium is a chemical element; it has symbol Fr and atomic number 87. It is extremely radioactive; its most stable isotope, francium-223 (originally called actinium K after the natural decay chain in which it appears), has a half-life of only 22 minutes. [4] It is the second-most electropositive element, behind only caesium, and is the second ...
1802 K. 1529 °C. 2784 °F. The Gmelin rare earths handbook lists 1522 °C and 1550 °C as two melting points given in the literature, the most recent reference [Handbook on the chemistry and physics of rare earths, vol.12 (1989)] is given with 1529 °C.
192 K, Debye temperature of ice. 273.15 K (0 °C), melting point of bound water. 273.16 K (0.01 °C), temperature of triple point of water. c. 293 K, room temperature. 373.15 K (100 °C), boiling point of bound water at sea level. 647 K, critical point of superheated water. 737.5 K, mean on Venus.
List of boiling and freezing information of solvents. Solvent. Density (g cm-3) Boiling point (°C) K b (°C⋅kg/mol) Freezing point (°C) K f (°C⋅kg/mol) Data source. Aniline.
CRC Press. Boca Raton, Florida, 2003; Section 6, Fluid Properties; Critical Constants. Also agrees with Celsius values from Section 4: Properties of the Elements and Inorganic Compounds, Melting, Boiling, Triple, and Critical Point Temperatures of the Elements. Estimated accuracy for T c and P c is indicated by the number of digits.
Astatine is a chemical element; it has symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth's crust, occurring only as the decay product of various heavier elements. All of astatine's isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours. Consequently, a solid sample of the ...
Isotopes of francium (87Fr) Francium (87 Fr) has no stable isotopes. A standard atomic weight cannot be given. Its most stable isotope is 223 Fr with a half-life of 22 minutes, occurring in trace quantities in nature as an intermediate decay product of 235 U. Of elements whose most stable isotopes have been identified with certainty, francium ...
Marguerite Catherine Perey (19 October 1909 – 13 May 1975) was a French physicist and a student of Marie Curie. In 1939, Perey discovered the element francium by purifying samples of lanthanum that contained actinium. In 1962, she was the first woman to be elected to the French Académie des Sciences, an honor denied to her mentor Curie.