Comparative Analysis of the Saturated Vapor Pressure of Halogenides of the Scandium Subgroup

Abstract

Experimental values for saturated vapor pressure (Psat) of halides of the scandium subgroup are systematized for the purpose of analyzing and predicting unexplored Psat. Comparative calculations are used for analysis, making it possible to compare the sought Psat to basic values graphically (Psat for CaF2).. Generalized analytical expressions of the form $$\log P$$ −1/T for all halides of elements of the Sc subgroup and dependence $$\log P$$ − $$\log {{P}_{{{\text{Ca}}{{{\text{F}}}_{2}}}}}$$ at different temperatures are obtained using the least squares approach. Linear correlations of the form $$\log P$$ − $$\log {{P}_{{{\text{Ca}}{{{\text{F}}}_{2}}}}}$$ are used to estimate correctly unknown values Psat of halides of the subgroup Sc. The special position of scandium and fluorine in the subgroups of Mendeleev’s periodic table is confirmed by the considerable difference between the properties of fluorides and similar values for chlorides, bromides and iodides. It is shown that the properties of scandium halides differ from those of the corresponding lanthanum and yttrium halides, and the properties of fluorides differ sharply from those of chlorides, bromides, and iodides, which have close values. The possibility of estimating Psat for compounds of actinium and astatide is shown.