Dysprosium parameters

Parameter Gadolinium Terbium Dysprosium Holmium Erbium ThuUmn Ytterbium Lutetium... 

Dy-Cu-Sb. A ternary compound of dysprosium with copper and antimony of the 3 3 4 stoichiometric ratio was identified and studied by means of X-ray analysis by Skolozdra et al. (1993). Dy3Cu3Sb4 compound was found to have the Y3Au3Sb4 type structure with a lattice parameter of a = 0.9503 (X-ray powder diffraction). For experimental details, see the Y-Cu-Sb system. 

Dysprosium(III) with f9 has 73 multiplet terms with 6Hi5/2 as the ground state. Crystal spectrum of DyCb in LaCb matrix has been analyzed and the calculated and observed energy levels use the following parameters A9(r2) 91.30 cm-1, A (r4) — 38.97 cm-1, Ag r6) — 23.17 cm-1, Ag(r6) 257.8 cm-1. The energy levels of Dy3+ in LaCl3 are given... 

The structure of the Y-B-C phase (Bauer and Nowotny 1971) consists of the B-B zigzag chains with C-branches and trigonal metal prisms, which is similar to that of the phases U-B-C (Toth et al. 1961) and MojBC (Jeitschko et al. 1963). Later work by Bauer and Debuigne (1972, 1975) also found phases with this type of structure in the R-B-C (R = Dy, Gd, Tb) systems. The Dy-B-C phase has lattice parameters a = 3.384 A, fe = 13.727 A and c = 3.647 A. The positions of atoms in the Djh-Cmmm space groups are four dysprosium atoms at 4i sites, y = 0.135 four boron atoms at 4j sites, y = 0.711 and four carbon atoms at 4j sites, y = 0.591. 

For all preparations of the dysprosium and ytterbium compounds as well as the compounds of M = Ga, Pb, second phases appear in the samples, showing that the compounds R3MC,. have an x value less than unity. From observations of the changes in lattice parameters with composition in the compound Nd3lnC, the limiting... 

The lattice parameter of the compounds R3 MC in the lanthanide series for a given element M changes linearly with the radius of the trivalent rare earth ions, following the lanthanide contraction regularity, except for europium and ytterbium which appear to have a variable-valence state. In the ytterbium-M (Al, Ga, In, Tl)-carbon system, the unit cell volume of the compound YbgMC, is larger than the value expected from the relationship mentioned above. In the europium-M(Al, Ga, In, Tl)-carbon system no compound was found. For the compounds of yttrium, as expected, the lattice parameter falls between those of the respective terbium and dysprosium compounds. 

Fig. 6.32. The temperature dependence of the lattice parameters of dysprosium (after Darnell, 1963).

However, calculations based on the dysprosium cross-section evaluation overestimated the worth of this material by about 5% in k ff. In obtaining these cross sections, the resonance. absorption integral had been normalized to the rejported measured value because use of the available resonance parameters gave a value some 3(X) b lower. Use of the unnormalized data in the calculations increased keff by some 6%, indicating that the measured resonance absorption integral value may be too high. 

TABLE 6.2 Dy Mossbauer Spectral Parameters of the Dysprosium Dicarboxylates ... 

In Chapters I and 2, an introduction is made to the synchrotron Mossbauer spectroscopy with examples. Examples include the/ns/tu Mossbauer spectroscopy with synchrotron radiation on thin films and the study of deep-earth minerals. Investigations of in-beam Mossbauer spectroscopy using a Mn beam at the RIKEN RIBF is presented in Chapter 3. This chapter demonstrates innovative experimental setup for online Mossbauer spectroscopy using the thermal neutron capture reaction, Fe (n, y) Fe. The Mossbauer spectroscopy of radionuclides is described in Chapters 4-7. Chapter 4 gives full description of the latest analysis results of lanthanides Eu and Gd) Mossbauer structure and powder X-ray diffraction (XRD) lattice parameter (oq) data of defect fluorite (DF) oxides with the new defect crystal chemistry (DCC) Oq model. Chapter 5 reviews the Np Mossbauer and magnetic study of neptunyl(+l) complexes, while Chapter 6 describes the Mossbauer spectroscopy of organic complexes of europium and dysprosium. Mossbauer spectroscopy is presented in Chapter 7. There are three chapters on spin-state switching/spin-crossover phenomena (Chapter 8-10). Examples in these chapters are mainly on iron compounds, such as iron(lll) porphyrins. The use of Mossbauer spectroscopy of physical properties of Sn(ll) is discussed in Chapter I I. 

The reliability of measurements of the partial pressures of R2CI6 can in principle be verified by a standard procedure based on changes in the thermod)mamic characteristics of these molecules along the lanthanide series. However, the enthalpy of atomization AatH°(298) is not the most convenient parameter for such a check since it does not vary monotoni-cally with the number of the lanthanides in the series. The plot of this dependence is a broken line with maxima at lanthanum, gadolinium, and lutetium compounds and minima at europium and ytterbium compounds. In addition, the enthalpy of atomization usually increases in going from dysprosium to erbium dimers. 

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