Quaternary Rare-earth Metal Chalcotrielates and Tetrelates

Quaternary Rare-earth Metal Chalcotrielates and Tetrelates 

We have developed a systematic study of quaternary chalco-gallates, indates (trielates) and chalco-silicates, and germinates (tetrelates) of the rare-earth metals. We have demonstrated that a series of new compounds could be formed in these families of materials [1, 3, 9, 10, 14, 81, 82]. There have been reports in the literature of a few examples of these types of materials, but there is sufficient evidence to support the fact that this area is wide open for exploring the likelihood for new rare-earth metal-based materials [83-90]. Our studies have focused on the gallium, indium, germanium and sihcon sulfides, selenides, and teUurides. 

Few examples of complex structures containing homonuclear Ge-Ge or Si-Si bonds have been described in the Hterature (see Fig. 14.1b). Isostructural ternary materials with the formula (A = Na, K M =Si, Ge Q=S, Se, Te) 

A series of quaternary europium structures containing two edge-shared tetra-hedra, see Fig. 14.1c), have been synthesized with a general formula 

In each representation, the alkali metal is black, the rare-earth element is shaded medium grey, the main group element is dark grey, and selenium is light grey (a) NagEu2(Si2Se6)2, 

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