510. Magnetochemistry of the heaviest elements. Part VII. Sodium plutonyl acetate

Abstract

The magnetic susceptibility of sodium plutonyl acetate, measured over the temperature range 90-300" K , follows the Curie law exactly and agrees with the theoretical spin-only value for two unpaired electrons. This is taken as evidence that the ground state of the plutonyl ion has a 6d2 electron configuration.RESULTS obtained by dilution in solid solution in the diamagnetic isomorphous thorium compounds have shown that uranium and plutonium tetrafluorides have susceptibilities at infinite dilution corresponding t o two and four unpaired electrons in the 6d and 5f energy levels respectively (J., 1951, 2889 ; 1952, 1185, 1882). The dioxides have approximately the same susceptibilities at infinite dilution as the fluorides but their behaviour with increasing concentration is more complex. It was of interest t o examine the sexivalent plutonium ion, which should have two unpaired electrons, and to determine whether these are in the 5f or the 6d level. The most readily characterised compound is sodium plutonyl acetate which should be magnetically dilute and has been shown to crystallise in a fluoritetype lattice (a = 10.64 A) isomorphous with sodium uranyl acetate (Zachariasen, '' The

Magnetic Properties of Organometallic and Coordination Compounds of Plutonium

“…Pu(C 5 H 5 ) 3 and (C5H5) 3 Pu-CENC 6 Hi1 (Fig. 7) show a similar tem perature dependence to that of PUCI3.…”

Equatorial Electronic Structure in the Uranyl Ion: Cs2UO2Cl4 and Cs2UO2Br4

“…Salts containing the linear actinyl ion AnO 2 2+ (An = U, Np, Pu, Am) were among the first systems selected for experimental investigations of the distinctive electronic structure of the actinide elements. − The metal–oxygen bonds were the primary focus of early research, but subsequent work has led to a growing appreciation of metal–ligand interactions in the equatorial plane as an important determinant of the chemistry of the actinyl moiety. The strong influence of equatorial coordination is exemplified by the discovery of ligands that can activate the usually inert oxo groups. − The stabilization of transient monopositive actinyl ions, , including in the gas phase, provides another illustration of the profound effect of equatorial complexation on electron distribution at the metal.…”