Talk:Fermium/Archive 1

Fifteenth element ever discovered
What does this mean exactly? Surely 99 had already been found! Dajwilkinson 02:47, 1 December 2007 (UTC)

Former Names
They should have mentioned centurium, a former name for fermium. --76.239.133.185 (talk) 16:56, 9 July 2011 (UTC)

Density
Needs to be added. Llywelyn2000 (talk) 05:14, 16 June 2010 (UTC)

 X  Not done because fermium has no known physical properties (color, hardness, luster, density, etc.) Density is bold as it was your request. --3.14159265358pi (talk) 23:51, 5 December 2011 (UTC)


 * This paper could have a predicted value. Double sharp (talk) 05:24, 9 September 2013 (UTC)
 * Also worth noting is that if we know the crystal structure and bond length here, the prediction is straightforward using unit cells.--Jasper Deng (talk) 06:15, 9 September 2013 (UTC)
 * Fm should crystallize in fcc, like the divalent Es. (So should Md and No, but Lr, being trivalent, should use hcp.) Any predictions on Fm–Fm, Md–Md, No–No or Lr–Lr bond lengths? (They're the only four known elements where I couldn't find a measured or predicted density value.) Double sharp (talk) 07:11, 9 September 2013 (UTC)

Estimated metallic radii (Rm) for Fm (0.198 nm), Md (0.194) and No (0.197), and Lr (0.171) are given in this 2010 book chapter (pp. 1628; 1635; 1639; 1644). The same reference says an earlier 1978 citation quoting an estimated radius of 0.194 for Fm, was "in close agreement". All four metals are expected to have close packed structures (i.e. a packing efficiency of no more than 74.048%) according to this 1976 paper (p. 243). Dividing their atomic weights (257; 258; 259; 266) by their atomic volumes (i.e. 4/3*π*(Rm3)*(1/0.74074)*Avogadro's constant) gives indicative densities of Fm 9.7(1)−10.3(3); Md 10.3(7); No 9.9(4); and Lr 15.6 g/cm3. This other 1976 paper gives a calculated density for Lr of 16.6 g/cm3 (p. 260), which is equivalent to a radius of 0.167(6) nm—quite close to the first figure I listed of 0.171. The densities vary with the cube of the radii so are very sensitive to a nanometre or two either way. I’d be inclined to list Lr as ~15.6−16.6 Sandbh (talk) 06:46, 11 June 2016 (UTC)
 * Thank you so much! I'll add these figures. Double sharp (talk) 08:53, 11 June 2016 (UTC)
 * OK, added to the infoboxes and list of elements (should be okay by WP:CALC). In circumstances when space must be conserved at the expense of detail, I'd probably write Fm ~10; Md ~10; No ~10; Lr ~16. Double sharp (talk) 09:09, 11 June 2016 (UTC)
 * That was allegro! Bravo! Sandbh (talk) 11:52, 11 June 2016 (UTC)
 * Thank you! (^_^) Double sharp (talk) 13:46, 11 June 2016 (UTC)
 * To be more transparent I should go back and add notes to the Fm, Md, No, and Lr infoboxes explaining these calculations. Double sharp (talk) 05:28, 28 November 2018 (UTC)

Arblaster's Selected Values of the Crystallographic Properties of Elements (2018) gives (p. 682): 257Fm 9.43, 258Md 9.69, 259No 9.95, 262Lr 16.82. Double sharp (talk) 19:23, 27 January 2024 (UTC)

Production of actinide isotopes
From Greenwood and Earnshaw, p. 1262: "237Np, 241Am and 243Am can be extracted from reactor wastes and are available in kg quantities. Prolonged neutron irradiation of 239Pu is used at the Oak Ridge laboratories in Tennessee to produce: 244Cm on a 100-g scale; 242Cm, 249Bk, 252Cf and 253Es all on a mg scale; and 257Fm on a &mu;g scale....the remaining three actinides, Md, No and Lr, can only be prepared by bombardment of heavy nuclei with the light atoms 4He to 20Ne. This raises the mass number in multiple units and allows the 258Fm barrier to be avoided; even so, yields are minute and are measured in terms of the number of individual atoms produced." Double sharp (talk) 05:06, 19 November 2016 (UTC)

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Untitled
Article changed over to new WikiProject Elements format by mav 05:39, 21 Feb 2004 (UTC). Elementbox converted 12:00, 17 July 2005 by Femto (previous revision was that of 17:14, 6 June 2005). 6 June 2005

Information Sources
Some of the text in this entry was rewritten from Los Alamos National Laboratory - Fermium. Additional text was taken directly from the Elements database 20001107 (via dict.org) and WordNet (r) 1.7 (via dict.org). Data for the table were obtained from the sources listed on the subject page and WikiProject Elements but were reformatted and converted into SI units.