A LANTHANIDE LANTHOLOGY (.pdf) - Davidson Physics
A LANTHANIDE LANTHOLOGY (.pdf) - Davidson Physics A LANTHANIDE LANTHOLOGY (.pdf) - Davidson Physics
PRASEODYMIUMtransport of Pr happens through the intermediacy of a transient PrMX n complex. The cause of thecoloration has been attributed solely to the Pr 4+ ion stabilized in the host ZrSiO 4 but it is alsopossible that charge transfer bands contribute. The color of potential red pigments such asCe l-x Pr x O 2 [5] is certainly due to charge transfer bands associated with the Ce(IV)/Pr(IIII)system.[6]A possible Pr(III)/Pr(IV) redox in a fluorite-related structure, with mobile oxide ions,indicates a potential for Pr in catalysis similar to that found for cerium in CeO 2 . As examples, theoxidative coupling of methane over doped Pr 6 O 11 shows a high selectivity to C 2 products[7] andthe oxide Pr 4 PdO 7 catalyzes the oxidation of natural gas fuels as well as having an excellentthermal stability and regenerative behavior[8].On excitation the Pr 3+ ion shows a variety of emissions depending strongly on the host latticedue to the strong influence of that lattice on the energy of the excited 4f5d level.[9] Pr-dopedfluoride fibers have been proposed for optical amplification at 1310 nm for telecommunications; asystem that could rival Erbium-doped fiber amplifiers. Another application of Pr-emission is in thescintillator Pr,Ce,F : Gd 2 O 2 S for X-ray computed tomography[10]. Such scintillators need to bemade as small translucent ceramics with an emitter with a very fast decay time, 5 µs for Pr 3+ , and awavelength matching the detector's sensitivity.Permanent magnets based Praseodymium, a lanthanide more abundant than Samarium, havethe potential to be comparable in properties to the well recognized samarium-cobalt material,SmCo 5 . Certain oxides, added as powders (up to 1 wt %) prior to sintering, can suppress theformation of undesirable impurity phases. The added oxide reacts with any excess Ln in the startingalloy composition and keeps the overall Pr : Co ratio down to the desired 1 : 5. One esoteric use ofthis element is in the intermetallic PrNi 5 that has made possible the attainment of ultra-lowtemperatures, in the micro-Kelvin range[11]. The l4l Pr nuclei have the requisite novel magneticproperties.[5] Optical Properties of Ce l-xPr xO 2 Powders and their Applications to the Coloring of Ceramics, R.Olazcuagaet al., J.Solid State Chem., 1987, 71, 570[6] Charge-Transfer Spectra of Tetravalent Lanthanide Ions in Oxides, H.E.Hoefdraad, J.Inorg.Nucl.Chem.,1975, 37, 1917[7] Methane Conversion, AM.Gaffney (Arco), U.S.Patent, 4,499,323, 12 Feb. 1985[8] Praseodymium-Palladiurn Binary Oxide, Catalyst Compositions containing the Same, and Methods of Use,T.C.Chou et al.(Engelhard), U.S.Patent 5,102,639, 7 April 1992.[9] Chemistry and Physics of R-Activated Phosphors, G.Blasse, in "Handbook on the Physics and Chemistry ofRare Earths", ed. K.A.Gschneidner and L.Eyring, publ. North-Holland, 1979, Vol.4, p.237[10] A Scintillator Gd 2O 2S : Pr, Ce, F for X-Ray Computed Tomography, H. Yamada et al.,J.Electrochem.Soc., 1989, 136(9), 271331
[11] A Double-stage Nuclear Demagnetization Refrigerator, R.M.Mueller et al., Cryogenics, 1980,25(7), 39532
- Page 2 and 3: ALANTHANIDELANTHOLOGYPart II, M - Z
- Page 6 and 7: Compounds of the perovskite, ABO 3
- Page 8 and 9: METALSThe lanthanides, when prepare
- Page 10: METALSMetallo-thermic oxide-reducti
- Page 13 and 14: MONAZITEMonazite, a light-lanthanid
- Page 15 and 16: NEODYMIUMNeodymium is the third mos
- Page 18 and 19: [2] Preparation, Phase Equilibria,
- Page 20 and 21: NOMENCLATURE58 - 71; the term is in
- Page 22 and 23: OXALATESAddition of oxalic acid, or
- Page 24 and 25: OXIDESCalcination in air for the th
- Page 26 and 27: OXIDESFurthermore oxides with Ln IV
- Page 28 and 29: OXYCHLORIDESThermal decomposition o
- Page 30 and 31: OXYSULFIDESAll the elements of the
- Page 32 and 33: PEROVSKITESA very wide range of mat
- Page 34 and 35: PHOSPHATESThe LnPO 4 compounds can
- Page 38 and 39: RESOURCESFor significant resources
- Page 40 and 41: RESOURCESSignificant new resources
- Page 42 and 43: SAMARIUMSamarium metal is made dire
- Page 44 and 45: SILICATESWithin the binary Ln 2 O 3
- Page 46 and 47: SOLVENT EXTRACTIONSome text books s
- Page 48 and 49: SULFATESLanthanide sulfates can be
- Page 50 and 51: SULFIDESThe thermochernistry of CeS
- Page 52 and 53: THULIUMThulium, the rarest of the "
- Page 54 and 55: TITANATES, TITANIUM DIOXIDELanthani
- Page 56 and 57: YTTERBIUMIn broad chemical behavior
- Page 58 and 59: YTTRIUMCompoundIdealFormulaFormula
- Page 60 and 61: YTTRIUM OXIDEThe very stable oxide,
- Page 62 and 63: YTTRIUM OXIDEThe widespread introdu
[11] A Double-stage Nuclear Demagnetization Refrigerator, R.M.Mueller et al., Cryogenics, 1980,25(7), 39532