UNCOMMON VALENCE STATES IN THE METALLIC LANTHANIDE AND ACTINIDE DIIODIDES MI(2) (M=LA, CE, ND, GD AND TH) AND IN THE URANIUM TELLURIDES UTE2, U2TE5 AND UTE3 .1. THE RARE-EARTH DIIODIDES LNI(2) (LN=LA, CE, ND, GD) AND THI2

The diiodides MI(2) (M=La, Ce, Nd, Gd and Th) were investigated concer ning both their crystal structure and their electronic properties. No inconstancies or anomalies in their unit cell parameters down to 12 K were found as indicators for the formation of charge density waves. Di fferent methods were applied to investigate the electronic properties of LaI2 and Cel(2). From conductivity measurements and photoelectron s pectroscopy we could confirm the metallic nature of these compounds. P hotoelectron spectroscopy was used to investigate the electronic struc ture, especially the orbital character of the conduction band. The con duction band is strongly dominated by d-states and, in the case of CeI 2, a remarkably small d-f hybridization. The latter fact was also the result of band structure calculations performed by Jepsen and Andersen [1]. In addition the magnetic susceptibility for LaI2 and CeI2 were r ecorded giving a moment of 0.5 and 2.28 mu(B), respectively.