The First Lanthanide Telluride-Bromide: La3Te4Br, a Valence Compound

Abstract

Abstract:The first ternary lanthanide telluride-bromide La 3 Te 4 Br was obtained from a mixture of LaTe and LaBr 3 (in the presence of iridium) in a sealed tantalum container at elevated temperatures. The crystal structure (orthorhombic, Pnma, a = 1634.3(2), b = 435.0(1), c = 1426.6(2) pm, Z = 4, R 1 (I 0 > 2(I 0 )) = 0.0349) is built from dicapped trigonal prisms of tellurium and bromine atoms surrounding lanthanum in two different ways. The dicapped trigonal prisms are connected via common edges to a threedimensional structure, in the same fashion as is known for the binary U 3 Te 5 . La 3 Te 4 Br is a valence compound according to (La

The First Rare‐Earth Metal Telluride Chlorides, RTeCl (R = La, Ce, Pr, Nd)

“…Although all of the rare‐earth metal oxide‐halides, R O X , are known structurally, comparably little is known for the heavier chalcogenide‐halides, RQX ( Q = S, Se, Te)6,7 and the least for telluride‐halides. Of the latter only a few have been reported, namely NdTeF,17 La 3 Te 4 Br,18 Er 1.73 Te 2.4 I 8 ,19 and La 2 TeI 2 20. Figure 2 compares the present knowledge of chalcogenide‐chlorides RQ Cl with R = La, Ce, Pr, Nd, of which we could now obtain the respective telluride‐chlorides, R TeCl.…”