Lanthanide Contraction in F ( = Ce-Lu) and Its Chemical and Structural Consequences: Part 1: Location of YF in the F Series According to Its Chemical and Structural Characteristics

A of 14 () from Ce to Lu consists of the interaction of nucleus with -electrons. (REEs-) include Sc, Y, La, and 14 . They are located in 4-6th periods of the subgroup of group III. The electronic structure divides into short (- Sc, Y, La) and long (14 -elements Ce-Lu) homologous series. The most important chemical consequence of LC is the creation of a new conglomerate of 16 F by mixing fluorides of - (Y, La) and -elements. This determines the location of YF among F. The location of YF depends on the structural (-) and thermochemical (temperatures and heats of phase transformations, phase diagrams) properties. The location of YF between HoF and ErF was determined by V at a () and (). The location of YF according to Δ and Δ is in a dimorphic () ( Er-Lu), but without the exact " Z". According to the () in F ( = Dy-Lu), YF is located in the SSGr between ErF and TmF. The ErF-YF and YF-TmF phase diagrams show it to be between ErF and TmF. The crystals of five -F ( = Ho-Lu) and -YF were obtained in identical conditions and their crystal structures were studied. V (at and ) with "" = 67.42 was calculated from the unit cell parameters, which were defined with ±5 × 10 Å accuracy. It determines the location of YF between HoF and ErF.