THE lutetium, symbol Lu and atomic number 71, is a chemical element of the Periodic Table belonging to the group of lanthanides (known as rare earth metals). It is a difficult metal to produce and can be obtained as a by-product of mining other lanthanides or through yttrium ores. In its metallic form, it has a grayish white color and is resistant to corrosion. In solution, like the other lanthanides, lutetium adopts the oxidation number equal to +3.
Lutetium is named after the city of Paris, the French capital. In ancient times, as in the Roman Empire, the city was called Lutetia. Although lanthanides are widely used in rapidly growing economic sectors, lutetium still has applications. restricted, such as in the manufacture of lasers, optical instruments, ceramics and in experimental treatments for severe cases of cancer.
See too: What are the internal transition elements?
Lutetium Summary
Lutetium is a metal belonging to the class of lanthanides or metals rare Lands.
In metallic form, it has a grayish white color.
In solution, its NOx is always +3.
It is generally obtained as a by-product of mining other lanthanides or yttrium.
Its production is hampered, being carried out by reduction with calcium.
There are few uses of lutetium, being more used in the manufacture of lasers, ceramics and optical instruments.
Its discovery is credited to Frenchman Georges Urbain.
Lutetium properties
Symbol: Lu
Atomic number: 71
Atomic mass: 174.9668 c.u.s.
Electronegativity: 1,27
Fusion point: 1663 °C
Boiling point: 3402 °C
Density: 9.841 g.cm-3 (at 25 °C)
Electronic configuration: [Xe] 6s2 4f14 5d1
Chemical series: rare earth metals, lanthanides
Characteristics of lutetium
Lutetium is a soft grayish white metal, stabilized against oxidation due to the formation of a thin oxide layer on its surface. In solution and in the form of compounds, lutetium has oxidation number equal to +3.
He reacts with all halogens, however, in the case of chlorine (Cl2), bromine (Br2) and iodine (I2), the halides are obtained through the reaction between lutetium (III) oxide with an aqueous solution of the corresponding hydrate. Initially the lutetium (III) halide is obtained in the hydrated form and then it must be dehydrated, either by means of heat or using a drying agent.
Lu2THE3 + 6 HCl → 2 LuCl3(OH2)6
profit3(OH2)6 → LuCl3 + 6 hours2THE
Lutetium has 50 known isotopes, however, only two occur naturally, being:
176Lu, stable, corresponding to 97.41% of natural lutetium;
175Lu, radioactive, with half life approximately 40 billion years, corresponding to 2.59% of natural lutetium.
the lutetium is in the discussion about the elements that must be below the yttrium and scandiumin group 3 of Periodic table. The doubt persists as to whether below the yttrium must be lanthanum and actinium or lutetium and laurence.
The truth is that IUPAC left the issue ambiguous, even having formed a working group to bring about a solution. Thus, in most Periodic Tables, lutetium is in the group of 15 elements known as rare earth metals, which starts with lanthanum and ends with lutetium itself.
Where can lutetium be found?
There is no mineral that has lutetium as its main constituent. Thus, much of its production occurs as by-product of yttrium mining, mainly in the minerals bastnasite and monazite. These two minerals have a large amount of rare earth metals in their composition, however lutetium (in the form of Lu2THE3) has less than 0.1% by mass in them.
Furthermore, it is noteworthy that the minerals that have higher mass amount of Lu2O3 are as follows:
xenotime, with 0.8% by mass;
eudialite, with 0.3% by mass;
fergusonite, with 0.2% by mass.
Read too: Cerium — another metal belonging to the lanthanide group
Obtaining lutetium
Obtaining lutetium in metallic and pure form is recent in the history of chemistry. In fact, it is believed to be one of the most difficult (if not the most difficult) elements to obtain. The main technique consists of LuCl reduction3 or LuF3anhydrous products using metallic calcium, in a reaction whose temperature reaches 1470 °C.
Another complicating factor is that such a reaction must take place under conditions of rarefied pressure, in the range of 10-4 pressure pascal (just for comparison, at sea level, the pressure is 101,325 pascal). The process reaction is as follows:
3 Ca (l) + 2 LuF3 (l) → 3 CaF2 (l) + 2 Lu (l)
The liquid mixture obtained is heterogeneous, facilitating the separation of fluoride from calcium of lutetium. Once separated, lutetium is solidified and then purified.
Applications of lutetium
The applications of lutetium are still scarce. Being the most expensive of all lanthanides, with a price in the range of US$ 100/g, lutetium is used in manufacture of optical lenses, ceramics and lasers.
the isotope 177Lu has been used in experimental treatments against severe cases of cancer. In this case, proteins bind to lutetium and use its ionizing radiation to destroy cancer cells.
How hafnium, lutetium can be used to geological dating. This technique, by the way, was used to quantify rare earth metals (including lutetium itself), in the mineral deposits of Bou Regreg River, in Morocco.
history of lutetium
element 71 was independently isolated for the first time in the year 1907, based on mineral samples that contained a good amount of ytterbium oxide, one of the last lanthanides. Thus, it is believed that lutetium was also part of the composition of this mineral sample. However, two scientists claimed to be responsible for the discovery of element 71.
The first, the Frenchman Georges Urbain, described that ytterbium, discovered in 1879 by Jean de Marignac, could be separated into two new elements: ytterbium (or neo-ytterbium) and lutetium. It turns out that these two elements were identical to the elements aldebarnium and cassiopeio. These were discovered by the Austrian Carl Auer von Welsbach.
In 1909, the International Commission on Atomic Weights dropped the hammer, and it was decided that Georges Urban he was the author of the discovery, keeping the lutetium name for the new element.
It is noteworthy that the word lutetium refers to the term lutetia, the former name of the city of Paris, the French capital, since in ancient times, as in the Roman Empire, the city was called Lutetia.
Interestingly, years after von Welsbach's cassiopeio was left behind, in 2009, Iupac made official the discovery of element 112, whose adopted name was copernicium. Initially, the symbol adopted would be Cp, but, due to cassiopeio (which used this symbol and still maintained in the German language to designate lutetium), Iupac decided to institute the symbol Cn for the element 112.
Exercises solved on lutetium
question 1
Lutetium, like the other lanthanides, presents, in solution, NOx +3. Which of the following substances has an element in this oxidation state?
A) LuF
B) LuCl2
C) Lu2THE3
D) LuBr4
E) Lu2I
Resolution:
Alternative C
THE fluorine has NOx equal to -1. The other halogens, in the absence of atom of oxygen in the formula, are also charged with -1. already the oxygen has a charge of -2. Thus, the calculation of the NOx of lutetium in each substance is given as follows:
LuF: x + (–1) = 0 → x = +1; so wrong answer.
profit2: x + 2(–1) = 0 → x – 2 = 0 → x = +2; so wrong answer.
Lu2THE3: 2x + 3(–2) = 0 → 2x – 6 = 0 → x = +3; so correct answer.
LuBr4: x + 4(–1) = 0 → x – 4 = 0 → x = +4; so wrong answer.
Lu2I: 2x + (–1) = 0 → 2x – 1 = 0 → x = +½; so wrong answer.
question 2
THE 177Lu has been used in the experimental treatment of some severe cases of cancer. When observing such an isotope, and knowing that the atomic number of the element is equal to 71, what is the number of neutrons in this isotope?
A) 177
B) 71
C) 248
D) 106
E) 108
Resolution:
Alternative D
The atomic number of Lu is equal to 71. So, the number of neutrons can be calculated by the following formula:
A = Z + n
where A is the number of atomic mass, Z is the atomic number, and n is the number of neutrons. Substituting the values, we have:
177 = 71 + n
n = 177 - 71
n = 106
By Stefano Araújo Novais
Chemistry teacher