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Lanthanides & Actinides
Lanthanide Metals
Production of Elemental Metals
La, Ce, Pr, Nd, Gd:
2MCl3 + 3Ca Æ 2M + 3CaCl2 (T > 1000 °C)
Tb, Dy, Ho, Er, Tm, Y:
2MF3 + 3Ca Æ 2M + 3CaF2 (MCl3 is too volatile)
PmF3 + 3 Li Æ Pm + 3LiF
Eu, Sm,Yb:
M2O3 + 2La Æ 2M + La2O3 (MCl3 reduced to MCl2 by Ca)
Mischmetall (mixed light Ln) :
electrolysis of fused LnCl3/NaCl with graphite anode & graphite or steel cathode
Structures of Elemental Metals
Example Structures:

View using CrystalMaker

Ce, CCP Structure

Gd, HCP Structure

Pr, hc(4H) Structure

Eu, BCC Structure

Properties of the Metals
  • Silvery white, but tarnish in air
  • Rather soft (later M are harder)
  • High mpt & bpt
  • Very reactive Ð (I1 + I2 + I3) comparatively low
    • (reactivity as atomic radius )
  • + H2O Æ M2O3 or M(OH)3 & liberates H2 ~ slowly in cold, rapidly on heating
  • + H+ (dilute acid) Æ Ln3+ & liberates H2 ~ rapid at room temperature
  • burn easily in air ~ slowly in cold , burn at T > 150 °C
    • Æ sesquioxides, M2O3
      (but Ce Æ CeO2) & (Y is passivated below 1000 °C due to its oxide coating)
    • Æ nitrides, MN
  • exothermic reaction with H2 Æ MHn (n = 2,3, often results in defect states)
  • react readily with C, N2, Si, P, halogens & other non-metals

    form binaries on heating with most non-metals (e.g. LnN, Ln2S3, LnB6, LnC2, ...)

Uses of Metals
  • <1% Mischmetall or Ln silicides improves strength & workability of low alloy steels for plate and pipes {also used in Mg alloys}
  • Mischmetall (50% Ce, 25% La, 25% other light lanthanides) is pyrophoric ~ alloyed with 30% Fe it is used in lighter flints
--Info & DownloadsBibliography  [textbook & online resources]

Source: Dr. S.J. Heyes; University of Oxford
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