O ytterbium, symbol Yb and atomic number 70, is a lanthanide (or rare-earth metal). It is a silver colored, ductile and malleable metal. Unlike the other lanthanides, ytterbium can present, in solution and in compounds, the oxidation number equal to +2 (while most lanthanides have only NOx equal to +3).
Ytterbium is an element of few uses, but it can be applied as a stainless steel improver, in portable X-ray devices and in the composition of atomic clocks. It is produced by metalothermic reduction, using lanthanum as the reducing metal.
Your discovered between the 18th and 19th centuries, based on ores sourced from the town of Ytterby, Sweden, home to virtually all rare earth metals. However, its name was only made official at the beginning of the 20th century, more precisely in 1909.
Read too: Scandium — metal capable of making good metal alloys
Topics of this article
- 1 - Summary about ytterbium
- 2 - Properties of ytterbium
- 3 - Characteristics of ytterbium
- 4 - Where can ytterbium be found?
- 5 - Obtaining the ytterbium
- 6 - Applications of ytterbium
- 7 - History of ytterbium
Summary about ytterbium
- Ytterbium is a metal belonging to the class of lanthanides or rare-earth metals.
- In metallic form, it has a silver color and shine, in addition to being malleable.
- Despite presenting NOx +3, characteristic of the lanthanides, it also presents NOx +2.
- It occurs in nature mixed with other lanthanides, such as xenotime and fergusonite.
- It is obtained through reduction with lanthanum.
- The uses of ytterbium are still limited, but it can be a steel improver and be used in atomic clocks.
- Its discovery occurred from the ores coming from the city of Ytterby, Sweden.
ytterbium properties
- Symbol: Yb
- atomic number: 70
- atomic mass: 173.054 a.u.u.a.
- electronegativity: 1,1
- Fusion point: 824°C
- Boiling point: 1196°C
- Density: 6.903 g.cm-3 (α allotrope), 6.966 g.cm-3 (β allotrope)
- Electronic configuration: [Xe] 6s2 4f14
- chemical series: rare earth metals, lanthanides
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characteristics of ytterbium
Ytterbium, symbol Yb, has a silver coloring and shine in metallic form, in addition to being soft, malleable and somewhat ductile. Despite being relatively stable, it is interesting that the metal be packed in closed containers in order to protect it from air and moisture. By the way, like the other lanthanides, Yb can suffer combustion in contact with air to form ytterbium III oxide:
4 Yb + 3 O2 → 2 Yb2O3
Note: The oxide can also be formed by the calcination of ytterbium salts and hydroxides.
In solution, ytterbium can also have NOx equal to +3, characteristic of all lanthanides, however, like europium (Eu) and samarium (Sm), ytterbium can present NOx equal to +2. This is a consequence of your electronic configuration, which ends in [Xe] 6s2 4f14. By losing the two electrons of the 6s subshell, the filled 4f subshell manages to guarantee stability to the Yb ion2+.
The ytterbium too has three allotropic forms: α (alpha), β (beta) and γ (gamma). The alpha form exists down to -13 °C, while the beta form is present at room temperature. At over 795 °C, the gamma form is formed. Ytterbium also has 33 isotopes, seven of which are stable.
Where can ytterbium be found?
the ytterbium not the main constituent of any ore. Lanthanides (and ytterbium is no exception) often occur mixed in nature. Bastnasite and monazite ores are the most commercially exploited for lower mass lanthanides. Thus, ytterbium, a heavier lanthanide, has a mass concentration (in the form of Yb2O3) less than 0.1% in them.
The main heavier lanthanide ores are xenotime (a yttrium phosphate, YPO4), eudialite, from the silicate group, and fergusonite, from the oxide class. In the xenothyme, the mass concentration (in the form of Yb2O3) of ytterbium is 5.8%, while in eudialite it is 2.3%, and in fergusonite, 1.4%.
Read too:Origin of names and symbols of chemical elements
Obtaining the ytterbium
Although historically ytterbium was obtained via reduction with potassium, currently, its best way to obtain it is by lanthanum reduction in induction furnaces, the so-called metalothermic reduction. In it, ytterbium III oxide is reduced by the action of lanthanum, obtaining ytterbium in the form of steam, which condenses and crystallizes at specific points in the induction furnace.
Yb2O3 (s) + 2 La (l) → 2 Yb (g) + La2O3 (s)
The operating temperature must be in the range of 1500 °C, while the pressure must be between 10-4 and 10-3 Shovel.
ytterbium applications
Little studied, the applications of ytterbium are still few. One of them is the fact that ytterbium improve interesting properties of stainless steel, such as strength and other mechanical properties. the isotope 169Yb, radioactive, is used in portable X-ray machines, used in places without electricity.
O isotope 174Yb can be used in atomic clocks, whose precision is at least one second in 50 billion years, that is, it would take 50 billion years for it to miss a single second of time (plus or minus).
history of ytterbium
the ytterbium began to be discovered in the 18th century, with a Swedish porcelain factory. In 1788, the factory's owner, Reinhold Geijer, also a chemist and mineralogist, described a black, non-magnetic mineral of density equal to 4.223, found in the Ytterby mine (Swedish city) by the amateur geologist Carl Axel Arrhenius. Arrenhius also sent a sample of this mineral to Professor Johan Gadolin of Åbo Akademi in Finland.
After some experiments, Gadolin concluded that the ore would have 31 parts of silica, 19 parts of alumina (actually beryllium), 12 parts of iron oxide plus 38 parts of an unknown “earth” (formerly, “earth” was a name for “oxides”).
In 1797, Anders Gustaf Ekeberg, a chemist from the Swedish town of Uppsala, re-evaluated Gadolin's data, concluding that, untrue, the ore contained 47.5 parts of the new oxide. Ekeberg proposed the name yttersten for the mineral and the name ytterjord (Swedish) or yttria (Latin) for the new oxide.
Over the years, it was concluded that yttria was not a simple yttrium oxide. In 1843, it was proved that there were also oxides of erbium and terbium. In 1878, Swiss chemist Jean de Marignac isolated ytterbia from yttria., going so far as to say that she would be the oxide of a new trivalent element, ytterbium, of molar mass 172 g.mol-1. However, in 1899, in Austria, scientists Franz Exner and Eduard Haschek presented spectroscopic evidence that Marignac's ytterbium was not a single element.
Six years later, also in Austria, Carl Auer von Welsbach used fractional crystallization to separate ytterbium from Marignac on two elements, calling them aldebarium and cassiopeium, presenting mass data for both in December 1907.
However, 44 days before Welsbach published his results, Georges Urbain presented to the Paris Academy the separation of ytterbium into two new elements: neoterbium and lutetium, also presenting its mass data. Urbain went so far as to say that Welsbach's work lacked evidence and was not quantitative.
Thus, in 1909, the International Committee on Atomic Weights (of which Urbain was a member) favored the Georges Urbain's nomenclature, placing neoyerbium (later just ytterbium) with a molar mass of 172 g.mol-1 and lutetium with a molar mass of 174 g.mol-1.
By Stefano Araujo Novais
Chemistry teacher
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