Ytterbium magnetic susceptibility

Ytterbium melts at 824°C vaporizes at 1,194°C electrical resistivity 25.0 microhm-cm Vickers hardness 21 kg/mm Young s modulus 0.182x10 kg/cm2 shear modulus 0.071x10 kg/cm Poisson s ratio 0.284 magnetic susceptibility 71x10 emu/mol thermal neutron absorption cross section 37 barns reacts slowly with water soluble in dilute acids and ammonia. 

The value of the Weiss constant 0 was 43 1°K and suggested that Eu2RuH6 becomes ferromagnetic at some temperature below 77°K. The magnetic susceptibility for Yt RuHe appeared to be consistent with di-valent ytterbium, which theoretically has zero atomic moment. The small paramagnetism observed experimentally was assigned to Yb23 impurity. 

Yb -83 at.% ) when present in the tetragonal dicarbide, which was confirmed by magnetic susceptibility measurements (Flahaut 1969), and trivalent in the cubic hypocarbide. In the sesquicarbide, the behavior of europium and ytterbium is anomalous. Ytterbium forms a monoclinic Yb2C3 phase (Haschke and Eick 1970a) while europium forms a tetragonal phase with a Ca2C3-type structure (Pasto and Morgan 1976, Schwetz et al. 1979). 

Grignard type compounds of some lanthanide metals in the oxidation state +2 have been investigated by D.F. Evans et al. (1970, 1971). Europium, samarium and ytterbium react in tetrahydrofuran with alkyl and aryl iodides between —20 and + 30°C forming colored solutions containing mixtures of compounds, which give some Grignard-type reactions. Characterization of the compounds was done only by magnetic susceptibility measurements and some titrimetric analyses. 

In addition to using the lattice parameter(s) of the RM compound to estimate the valence state of europium and ytterbium one can use magnetic susceptibility data (Gschneidner 1969b, Wohlleben 1981) and Lm absorption edges, XPS and UPS (Wohlleben 1981) to distinguish between the 4f" and 4f" configurations and intermediate valences. For europium one can also use Mossbauer isomer shift data (Brix et al. 1964, Clifford 1967, van Steenwijk and Buschow 1977, de Vries et aL 1984). 

D.F.Evans prepared divalent organo ytterbium for the first time by the reaction of ytterbium metal with organic halides in THF at - 20 C. Magnetic susceptibility measurements showed that 75-92% of the ytterbium is present in the divalent state. Samarium reacts more slowly, giving a mixture of divalent and trivalent species, as expected from the greater instability of the divalent state when Sm is compared to Yb (30). These solutions give Grignard-like reactions for example, PhSmI reacts with benzophenone to afford Ph C(OH) in 72% yield. 

Thus magnetic susceptibility measurements provide an interesting means of evaluating percentages of Ln and Ln + ions in a mixture of species. Effective magnetic moments of divalent samarium and ytterbium compounds are listed in table 5. 

The magnetic susceptibilities of CeNi2P2 and YbNi2P2 at 7 >50K are temperature independent and increase at lower temperatures (Jeitschko and Reehuis 1987). This is explained by deviations of the valence state of cerium and ytterbium from 3+ to 4+ and 2+, respectively. 

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