Binary lanthanide oxides

Eyring L., The Binary Lanthanide Oxides Synthesis and Identification, in Synthesis of Lanthanide and Actinide Compounds, eds, Morss L.R. and Meyer G. (Kluwer, Dordrecht 1991), 187-224. 

A review of the binary lanthanide oxides has already appeared in an earlier volume of this series (Eyring 1979). A review of the Seltenerdelemente appeared in Gmelin Handbuch der Anorganischen Chemie (1974). The preparative methods and characterization of the many phases of the lanthanide oxides have recently been published (Eyring 1991). The structures and transformations of the rare-earth oxides have recently been reviewed (Schweda et al. 1991, Schweda 1992). Some aspects of these reviews are summarized and brought up-to-date here. A review of thermodynamic properties can be found in the chapter by Morss (ch. 122) in this volume. 

X, powder pattern comparison. Stoichiometric mixtures of the binary lanthanide oxides heated at 1350 °C. for 4h under streaming HjS. 

Table 15. Enthalpy change of the dissociation reactions for selected molecules of binary group IVb, Vb, VIb, and lanthanide oxides...

Magnetic properties of binary lanthanide and actinide oxides... 

The synthesis of lanthanide and actinide compounds is the topic of a book edited by Meyer and Morss (1991). Topics that relate to halides, with the author(s) in brackets, include Lanthanide fluorides [B.G. Muller], Actinide fluorides [N.P. Freestone], Binary lanthanide(III) halides, RX3, X = Cl, Br, and I [G. Meyer], Complex lan-thanide(III) chlorides, bromides and iodides [G. Meyer], Conproportionation routes to reduced lanthanide halides [J.D. Corbett], and Action of alkali metals on lanthanide(III) halides an alternative to the conproportionation route to reduced lanthanide halides [G. Meyer and T. Schleid]. Meyer and Meyer (1992) reviewed lanthanide halides in which the valence of the lanthanide was considered unusual, with unusual being defined as compounds in which the localized valence of an atom differs from its oxidation number. A metallic halide such as Lalj [oxidation number (0)= -1-2 valence (V)= -l-3, since the 5d electron is delocalized in the conduction band] or a semiconducting halide such as PrjBtj (O = -t- 2.5 V = -I- 3) is unusual by this definition, but Tmlj (O = -1-2 V = +2) is not. In this review synthesis, properties, and calculated electronic structures are considered with emphasis on praseodymium halides and hydrogen intercalation into lanthanide dihalides and monohalides . 

Comparable recent detailed reviews of the actinide halides could not be found. The structures of actinide fluorides, both binary fluorides and combinations of these with main-group elements with emphasis on lattice parameters and coordination poly-hedra, were reviewed by Penneman et al. (1973). The chemical thermodynamics of actinide binary halides, oxide halides, and alkali-metal mixed salts were reviewed by Fuger et al. (1983), and while the preparation of high-purity actinide metals and compounds was discussed by Muller and Spirlet (1985), actinide-halide compounds were hardly mentioned. Raman and absorption spectroscopy of actinide tri- and tetrahalides are discussed in a review by Wilmarth and Peterson (1991). Actinide halides, reviewed by element, are considered in detail in the two volume treatise by Katzet al. (1986). The thermochemical and oxidation-reduction properties of lanthanides and actinides are discussed elsewhere in this volume [in the chapter by Morss (ch. 122)]. 

Methods involving homogeneous precipitation of the hydroxycarbonate of the lanthanides followed by calcining can be utilized to obtain colloidal particles of binary or ternary lanthanide oxides with varied morphologies. This technique has been thoroughly described by Matijevi c and by Hsu et al. (1988). Kang et al. (1992b) have... 

Many of the binary compounds of the lanthanides, such as oxides, nitrides, and carbides, can exist as non stoichiometric compounds. These form crystals where some of the anions ate missing from the sites the anions normally occupy. 

Synthesis in liquidAl Al as a reactive solvent Several intermetallic alu-minides have been prepared from liquid aluminium very often the separation of the compounds may be achieved through the dissolution of Al which dissolves readily in several non-oxidizing acids (for instance HC1). For a review on the reactions carried out in liquid aluminium and on several compounds prepared, see Kanatzidis et al. (2005) binary compounds are listed (Re-Al, Co-Al, Ir-Al) as well as ternary phases (lanthanide and actinide-transition metal aluminides). Examples of quaternary compounds (alumino-silicides, alumino-germanides of lanthanides and transition metals) have also been described. As an example, a few preparative details of specific compounds are reported in the following. 

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