• yttrium
  • Some mantles still use thorium, but yttrium oxide (or sometimes zirconium oxide) is used increasingly as a replacement. (wikipedia.org)
  • The first such mineral discovered was gadolinite, a mineral composed of cerium, yttrium, iron, silicon and other elements. (wikipedia.org)
  • Thus by 1803 there were two known rare-earth elements, yttrium and cerium, although it took another 30 years for researchers to determine that other elements were contained in the two ores ceria and yttria (the similarity of the rare-earth metals' chemical properties made their separation difficult). (wikipedia.org)
  • uranium dioxide
  • Note that the thermal conductivity of uranium dioxide is very low when compared with uranium, uranium nitride, uranium carbide and zirconium cladding material. (wikipedia.org)
  • citation needed] Uranium oxide fuel pellet Starting material containers for uranium dioxide fuel pellet production at a plant in Russia The thermal conductivity of zirconium metal and uranium dioxide as a function of temperature Play media Uranium oxide (urania) was used to color glass and ceramics prior to World War II, and until the applications of radioactivity were discovered this was its main use. (wikipedia.org)
  • Zinc
  • Although neither zinc nor zirconium are ferromagnetic, their alloy ZrZn 2 exhibits ferromagnetism below 35 K. A bar of zinc generates a characteristic sound when bent, similar to tin cry. (wikipedia.org)
  • electrons
  • Most lanthanides can use only three electrons as valence electrons, as afterwards the remaining 4f electrons are too strongly bound: cerium is an exception because of the stability of the empty f-shell in Ce4+ and the fact that it comes very early in the lanthanide series, where the nuclear charge is still low enough until neodymium to allow the removal of the fourth valence electron. (wikipedia.org)
  • silvery-white
  • Cerium is a soft, ductile and silvery-white metal that tarnishes when exposed to air, and it is soft enough to be cut with a knife. (wikipedia.org)
  • made
  • It wasn't until the 1920s that Aston and Lindemann made an isotope separator and found there were two isotopes at least on neon. (oclc.org)
  • cobalt
  • I had called Dr. Nuttall, a professor of chemical and nuclear engineering at UNM, to ask about isotopes, half-lives, tritium, uranium and cobalt. (alibi.com)
  • Much of the radioactive waste entombed there was containerized, in particular, the much-feared isotope, cobalt-60. (alibi.com)
  • elements
  • They split them off in different directions, and they discovered that they were isotopes, and then they began looking for isotopes of other elements. (oclc.org)
  • Despite always being found in combination with the other rare-earth elements in minerals such as monazite and bastnäsite, cerium is easy to extract from its ores, as it can be distinguished among the lanthanides by its unique ability to be oxidized to the +4 state. (wikipedia.org)
  • involves
  • The production of the second-most important isotope 247Bk involves the irradiation of the rare isotope 244Cm with high-energy alpha particles. (wikipedia.org)
  • Upon cooling below −15 °C, γ-cerium starts to change to β-cerium, but the transformation involves a volume increase and, as more β forms, the internal stresses build up and suppress further transformation. (wikipedia.org)
  • known
  • There are ten known isotopes of rutherfordium, having mass numbers that range from 253 to 262, the isotope with the longest measured half-life being 261 Rf (half-life of approximately 1.1 minutes). (encyclopedia.com)
  • occurs
  • For example, a volume change of about 10% occurs when cerium is subjected to high pressures or low temperatures. (wikipedia.org)
  • forms
  • In PUREX plants the zirconium sometimes forms a third phase which can be a disturbance in the plant. (wikipedia.org)
  • The zirconium forms the third phase by forming small particles which stabilise the emulsion which is the third phase. (wikipedia.org)
  • example
  • Today, cerium and its compounds have a variety of uses: for example, cerium(IV) oxide is used to polish glass and is an important part of catalytic converters. (wikipedia.org)
  • half
  • All of the remaining radioactive isotopes have half-lives that are less than 7004126000000000000♠3.5 h, and the majority of these have half-lives that are less than 4 minutes. (wikipedia.org)
  • thus
  • however, this effect is not yet strong enough at cerium and thus the 5d subshell is still occupied. (wikipedia.org)
  • another
  • Another major use in the past was in gas mantle of lanterns, which are composed of 99 percent ThO2 and 1% cerium(IV) oxide. (wikipedia.org)