857. The potassium thorium fluorides

Abstract

The compound a-K5ThF, has not previously been described. The compound K,ThF, is stable only a t high temperatures and has been shown to disproportionate a t lower temperatures into a mixture of P-K,ThF, and P-K,ThF,. Discordant views in the literature as to the formula of the compound of highest thorium fluoride content have been discussed, and the formula KTh,F,, for this compound confirmed. Partial solid solution has been shown to occur between KTh,F,, and ThF,. Optical properties have been recorded for the majority of the compounds listed.Systematic precipitation studies in the systems KF-Th(NO,),-H,O and KN0,-Th(NO,),-HF-H,O have shown that cationic complexes of thorium and fluorine strongly influence the composition of the precipitated potassium thorium fluorides. The hydrated compounds a-K,ThF,,nH,O, KTh,F,,nH,O, and ThF,,nH,O have been isolated from solution, but the compound KThF,,nH,O could not be isolated in a substantially pure state. Lattice water in the precipitated phases can be removed a t 300" without appreciable loss of fluorine.THE preparation of hydrated potassium thorium fluorides approximating in composition to K,ThF,, KThF, (probably a mixture of K,ThF, and KTh,F9), and KTh,F, (Rosenheim, Samper and Davidsohn, 2. autorg. Chem., 1903, 35, 424) suggests a considerable degree of complexity for the binary system KF-ThF,. Ample confirmation of this complexity was obtained from preliminary studies of the system and from the results of Dergunov and

The Crystal Structures of CsTh6F25 and NaTh3F13

“…This compound is isostructural to the NaNp 3 F 13 formulation made previously by Cousson [37]. However, similar phases of the formula ATh 3 F 14 (A = Cs, Rb, K) have been identified by either single crystal [3,14] or powder diffraction [7], but having different structures. The structure of 2 differs greatly from these isoformulaic phases.…”

Hydrothermal Descriptive Chemistry and Single Crystal Structure Determination of Cesium and Rubidium Thorium Fluorides

“…It is reasonable to assume that smaller alkali cations Na + and K + would be very weakly bound in the channels of this structure type and would perhaps adopt a different structure type for an ATh 3 F 13 formulation. As such, the KTh 3 F 13 formulation has only been proposed in a hexagonal crystal system based on crystal morphology and thermal analysis data, 6 and no space group or unit cell parameters were reported.…”

Molar refractivity as a diagnostic tool for determining composition of transition-element fluoride complexes

“…Thus, from optical measurements and a simple density determination, the stoichiometry was shown to be (NH4)4ThF8 rather than (NH4)8ThF7 or (NH4)2ThF6. The formula (NH4)4ThF8 was later confirmed by chemical analysis and a structure determination.3 4 The molar refractivities of the complexes 2KF PtF4 and 2RbF-PtF4 are nearly coincident with the values for the corresponding UF4 complexes. This suggests that the values of U(IV)-F complexes, more of which are known than of the Pt(IV) complexes, could serve as a basis for an estimate for A"af.píf, and for 7?ptF, itself.…”