Tris salts, structural parameters

Figure 3. The lattice parameter for the family of rock-salt structure actinide-antimonide compounds is shown where the line is for the corresponding lanthanide compounds. The metallic radii for the light actinide elements are plotted. The smooth line simply connects Ac to the heavy actinides. In both cases the smooth line represents the ideal tri-valent behavior.

Solvation and Shift Reagents.—The solvation parameters for a series of alcohols have been determined using the n.m.r. chemical shift of tris-n-butylphosphine oxide. Ion pair association between tetraphenylboron and cationic centres was used to study the electronic structure of aminonaphthylphosphonium salts (24 X = Ph4B ). Shift reagents have been used in the conformational analysis of adenosine phosphates and aromatic solvent induced shifts to probe the stereochemistry of butadienylphosphonates and their polymers. The geometries of difluorophosphine derivatives were evaluated from liquid crystal n.m.r. studies with the aid of electron diffraction. ... 

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)]. 

We now turn our attention to the s and s-p bonded metals, or the elements in groups lA-IVA. We include the IVA elements even though they are not metals because their elastic properties behave similar to the simple metals because of their s and p bonds. Lacking a rational model for their attractive potential, such as the Coulomb potential model that can be used for the ionically bonded salts, the best that can be done is to try to fit one of the empirical potential functions such as the Morse potential, the Buckingham potential, or the Mie potential that were discussed in Chapter 3 to their measured properties. However, since it is necessary to use most of the observed properties to calculate the parameters needed to fit the potential, there is little left to predict. Also, it should be mentioned that the relation between the 1-D and 3-D central force potential, based on the number of bonds between the ions in the NaCl structure, would not be the same for fee, hep, or bcc structures. Hence the relations develop for the NaCl system. Equations 7.34 through 7.37 are not valid for other systems. 

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