Terbium physical properties

Carl Gustaf Mosander, a Swedish chemist, successfully separated two rare-earths from a sample of lanthanum found in the mineral gadolinite. He then tried the same procedure with the rare-earth yttria. He was successful in separating this rare-earth into three separate rare-earths with similar names yttia, erbia, and terbia. For the next 50 years scientists confused these three elements because of their similar names and very similar chemical and physical properties. Erbia and terbia were switched around, and for some time the two rare-earths were mixed up. The confusion was settled ostensibly in 1877 when the chemistry profession had the final say in the matter. However, they also got it wrong. What we know today as erbium was originally terbium, and terbium was erbium. 

Berkelium is a metallic element located in group 11 (IB) of the transuranic subseries of the actinide series. Berkelium is located just below the rare-earth metal terbium in the lanthanide series of the periodic table. Therefore, it has many chemical and physical properties similar to terbium ( Tb). Its isotopes are very reactive and are not found in nature. Only small amounts have been artificially produced in particle accelerators and by alpha and beta decay. 

Ionic radius TbJ+ 0,93 A, Tb4+ 0.76 A. Metallic radius 1.783 A. First ionization potential 5.84 eV second 11.52 eV, Other physical properties of terbium are given under Rare-Earth Elements and Metals. See also Chemical Elements. 

Lanthanide elements (referred to as Ln) have atomic numbers that range from 57 to 71. They are lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). With the inclusion of scandium (Sc) and yttrium (Y), which are in the same subgroup, this total of 17 elements are referred to as the rare earth elements (RE). They are similar in some aspects but very different in many others. Based on the electronic configuration of the rare earth elements, in this chapter we will discuss the lanthanide contraction phenomenon and the consequential effects on the chemical and physical properties of these elements. The coordination chemistry of lanthanide complexes containing small inorganic ligands is also briefly introduced here [1-5]. 

The main focus of research on the rare earth silicates has been their preparation and structure. A summary of the structural data available is presented in table 14. In many cases the physical properties are unknown. An important application of the rare earth silicates is the use of yttrium oxyorthosilicate activated with terbium as a luminescent material in fluorescent lamps. Several patents have been published in this field. 

Figure 11.23 Photo luminescence spectra (Xex = 285nm Xem=545nm) of Tb(tba-PMP)3(TPPO), Tb(tba-PMP)3(H20), and Tb(tba-PMP)3(phen) measured from their 80 nm vacuum evaporated films on quartz substrates [62]. (Reprinted with permission from H. Xin et al., The effect of different neutral ligands on photo luminescence and electroluminescence properties of ternary terbium complexes, The Journal of Physical Chemistry B, 108, 10796-10800, 2004. 2004 American Chemical Society.)...

Reprinted with permission from H. Xin et al., The effect of different neutral ligands on photoluminescence and electroluminescence properties of ternary terbium complexes, The Journal of Physical Chemistry B, 108, 10796-10800, 2004. 2004 American Chemical Society.)... 

Terbium is classified as a rare earth element. The term is misleading because terbium is not especially rare in Earth s crust. It is more abundant than better known metals such as silver and mercury. Although the rare earth elements are not actually scarce, they were once very difficult to separate from each other. They have physical and chemical properties very similar to each other. 

Sm(lll) has a similar resonance energy level as Eu(lll). The physical and chemical properties of the two ions are also similar [11]. So samarium complexes emit fluorescence in the same sequence as that of europium complexes with different p-diketone ligands. Tb(IIl) has a higher resonance energy level. The fluorescence of Tb(Ill) complexes decrease in a different way to that of Eu(lll) and Sm(lll) complexes. Tb(acac)3Phen emits the most intense fluorescence in the terbium complexes. The reason is that the triplet state of acac is 25300 cm, much higher... 

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