Erbium compounds

An optical microcavity produced by the latter process has been applied to tune the emission from erbium-doped PS [Zh6], Erbium compounds like Er203 are known to exhibit a narrow emission band at 1.54 pm, which is useful for optical telecommunications. Several methods have been used to incorporate erbium in PS. A simple and economical way is cathodic electrochemical doping. External quantum efficiencies of up to 0.01% have been shown from erbium-doped PS films under electrical excitation [Lo2]. The emission band, however, is much broader than observed for Er203. This drawback can be circumvented by the use of an optical cavity formed by PS multilayers. In this case the band is narrowed and the intensity is increased because emission is only allowed into optical cavity modes [Lo3]. 

Erbium is fairly stable in air. It does not react with oxygen as quickly as most other lanthanoids. Erbium compounds tend to be pink or red. They are sometimes used to color glass and ceramics. 

The erbium compound decomposes upon heating in hexane with formation of a pink solution, which contains the lithium salt of the homoleptic anion [Er CH(SiMe3)2 4] . This complex could not be prepared independently via chlo-ride-silyl exchange from [Li(THF)4][Er CH(SiMe3)2 3C1] and excess LiCH(SiMe3)2. 

Thus, Mosander s activities led to the originally two-element division into a six-element division. The cerium compounds are yellow at the higher oxidation level and colourless at the lower oxidation level, lanthanum compounds are white, didymium compounds are red, yttrium and erbium compounds are white, terbium compounds are pink. Chemists existed, of course, who disputed the existence of these elements. Unequivocal identification of elements was, however, possible in later times only. In the period in question, the main characteristics on the basis of which a substance could be qualified as a new element were separability, colour, crystal shape and reactivity. Even atomic mass determinations were largely uncertain, particularly in the group of the rare earth elements, it will be seen in the... 

Figure 9.11 DTA curves of the glass 50GeO2 40PbO 10PbF2, with various erbium compounds used as doping species. The arrow points out the crystallization peak of the Pbp2 phase. Reproduced from reference 20. Copyright (2003) Elsevier Ltd...

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