Dysprosium bromide

Cu3As TRICOPPER ARSENIDE 604 DyBr3[g] DYSPROSIUM BROMIDE (GAS) 646... 

Figure 12.13 TG and DTC curves of complexes of gadolinium bromide (-----) and dysprosium bromide (---) with mechanism is F2...

Formation of such complex compoimds, but already with alkali-metal halides, has foimd application in the manufacture of modern metal halide lamps (Bom et al., 2004 Hilpert and Niemann, 1997), which have an emission spectmm close to that of the natural sunlight. Relevant iodides and bromides (particularly cerium and dysprosium bromides and iodides) were foimd to be the most suitable components of binary compoimds for the production of lamp vessels from silica glass (Markus et al., 2005). Further technological developments led to the replacement of vessel material by polycrystalline alumina and to the use of rare-earth chlorides for improving lamp characteristics (Rutkowska et al., 2004). 

Lanthanide bromides and iodides have found important applications in a completely different field. They are added as additives in high-pressure discharge lamps in the lighting industry to improve the arc stability and the colour quality. The latter is due to the contribution of the multiline spectrum of the doped rare earths which are added to the salt mixture. Lanthanide trihalides of dysprosium, holmium, thullium, gadolinium and lutetium are used frequently for this purpose (Hilpert and Niemann, 1997). 

Similar dimeric structures are also encountered with bromides. In the case of Gd compound, tetramers have been reported containing two non-equivalent Gd3+ ions with formal coordination numbers of 8 and 9. These tetrameric units form the basic building blocks of compounds like [CpiGdBr] resulting in polymeric infinite double chains. The dysprosium compound [Cp2DyCl]oo has also the polymeric structure. The structure [62] of tetrameric [Cp2GdCIU is shown in Fig. 6.5. 

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