High temperature allotropy and thermal expansion of the rare-earth metals

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By means of high temperature X-ray techniques the crystal structure of lanthanum, cerium, praseodymium, neodymium, ytterbium, and possibly gadolinium was found to be body-centered cubic at temperatures near their respective melting points. For ytterbium a hexagonal close-packed structure was also observed, which was shown to be stabilized by atmospheric impurities. Evidence for possible high temperature crystalline transformations in gadolinium, terbium, dysprosium, holmium, and lutetium was obtained by means of electrical resistance measurements; erbium gave no such evidence. X-ray data were used to derive empirical equations which describe thermal expansions coefficients of scandium, yttrium and the rare-earth metals. Europium exhibits a ... continued below

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Spedding, F. H.; Hanak, J. J. & Daane, A. H. August 17, 1960.

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By means of high temperature X-ray techniques the crystal structure of lanthanum, cerium, praseodymium, neodymium, ytterbium, and possibly gadolinium was found to be body-centered cubic at temperatures near their respective melting points. For ytterbium a hexagonal close-packed structure was also observed, which was shown to be stabilized by atmospheric impurities. Evidence for possible high temperature crystalline transformations in gadolinium, terbium, dysprosium, holmium, and lutetium was obtained by means of electrical resistance measurements; erbium gave no such evidence. X-ray data were used to derive empirical equations which describe thermal expansions coefficients of scandium, yttrium and the rare-earth metals. Europium exhibits a rapidly decreasing coefficient of expansion with increasing temperature, which may be a consequence of a gradual promotion of one of the 4f electrons into the conduction band. The hexagonal rare-earth metals were found to have nearly the same axial ratio at their respective transformation temperatures.

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  • Report No.: IS-187
  • Grant Number: None
  • DOI: 10.2172/1114463 | External Link
  • Office of Scientific & Technical Information Report Number: 1114463
  • Archival Resource Key: ark:/67531/metadc870629

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Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

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  • August 17, 1960

Added to The UNT Digital Library

  • Sept. 16, 2016, 12:32 a.m.

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  • Oct. 26, 2017, 6:59 p.m.

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Spedding, F. H.; Hanak, J. J. & Daane, A. H. High temperature allotropy and thermal expansion of the rare-earth metals, report, August 17, 1960; Ames, Iowa. (digital.library.unt.edu/ark:/67531/metadc870629/: accessed November 24, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.