Lanthanide Characteristics

Lanthanides are the chemical elements that range from Lanthanum to Lutetium. They share common characteristics, for which they are classified in a special category at the bottom of the periodic table.

Main characteristics of lanthanides:

• They are located in period 6 of the periodic table.
• They cover 15 elements, from 57 to 71.
• They share the structure of Lanthanum, to which is added an energy level f, which is less chemically reactive.
• They were called rare earths because in a natural state they are always combined to form oxides.
• Some are relatively abundant.
• Although they have variable valences, most have valences +3.
• As its atomic number increases, its radius decreases.
• They all have a shiny metallic look.

Individual characteristics of lanthanides:

Lanthanum (La).

• Atomic number 57
• Atomic Weight: 139
• Solid state
• Appearance: Metallic, silver white
• Valencias: +3
• Melting point: 920 ° C
• Boiling point: 3457 ° C

It was discovered in 1839. In industry it is used in alloys with other lanthanides to make lighter stones; in optics it is used for optical glasses. It is also used for hydrogen sponges, used to contain gases. In medicine it is used in the form of lanthanum carbonate, for the treatment of kidney failure, as it has an affinity to mix with phostates, reducing hyperphosphemia.

Cerium (Ce)

• Atomic number 58
• Atomic Weight: 140
• State: Soft solid
• Appearance: Metallic, silver gray, iron-like
• Valencias: +3, +4
• Melting point: 798 ° C
• Boiling point: 3426 ° C

It was discovered in 1803. It is the most abundant lanthanide. It is used to make catalysts, mainly for automobiles (catalytic converters) and for oil cracking. In oxide form it is used to polish glasses and lenses. Although it has no known biological functions, in medicine it is used in burn ointments.

Praseodymium (Pr)

• Atomic number 59
• Atomic Weight: 144
• State: Soft solid
• Appearance: Metallic, silver white
• Valencias: +3
• Melting point: 931 ° C
• Boiling point: 3520 ° C

It was discovered in 1841 and isolated in 1885. In the industry it is used in alloys with magnesium to make airplane engines; It is used to give glass and enamels a yellow color. Nickel alloys have magnetic properties. Reacts with halogens to produce fluorides, chlorides, bromides and iodides.

Neodymium (Nd)

• Atomic number 60
• Atomic Weight: 139
• Solid state
• Appearance: Metallic, silver white
• Valencias: +3
• Melting point: 1024 ° C
• Boiling point: 3100 ° C

It was discovered in 1885, when praseodymium was isolated; neodymium was isolated until 1925. It is one of the most reactive lanthanides. In industry it is used to color glass and enamels. Because of its ability to absorb light, it is used in astronomy to create crystals with which infrared spectrometers and filters are calibrated. One of its main uses is to make magnets of high magnetic intensity. These magnets are used for precision instruments, such as those used in computer hard drives, as well as some thin-format speakers.

Promethium (Pm)

• Atomic number 61
• Atomic Weight: 145
• Solid state
• Appearance: ?
• Valencias: +3
• Melting point: 1100 ° C
• Boiling point: 3000 ° C

Its existence was predicted in 1902, but could not be proven until 1944. This lanthanide is not found in nature, being the source of its obtaining and study the fission of uranium. When uranium fissions in a nuclear reactor, one of the atoms that are produced from this atomic separation is the promethium. It has radioactive characteristics, which give it phosphorescence, and it is used for calibrators and nuclear batteries used in spacecraft.

Samarium (Sm)

• Atomic number 62
• Atomic Weight: 150
• Solid state
• Appearance: Metallic, silver white
• Valencias: +3
• Melting point: 1072 ° C
• Boiling point: 1803 ° C

It was discovered in 1853 and isolated in 1879. It has several isotopes, and at least two of them are radioactive. In industry it is used in optics to make crystals that absorb infrared light. It is also used as a catalyst to obtain alcohol, and as an element in some fluorescent lamps and televisions. As for health, if inhaled (such as the oxide used to polish crystals), it can cause pulmonary embolisms or affect the liver. Radioactive isotopes are used in radiotherapy of terminally ill patients.

Europium (Eu)

• Atomic number 63
• Atomic Weight: 152
• Solid state
• Appearance: Metallic, silver white
• Valencias: +2, +3
• Melting point: 826 ° C
• Boiling point: 1527 ° C

It was discovered in 1890. It is the most reactive of the lanthanides. It has been used in fluorescent lamps and televisions, however for causing pulmonary embolisms if it is inhaled or damage the liver if accumulated in the human body, it has almost no industrial uses. In atomic research it is used since it absorbs neutrons.

Gadolinium (Gd)

• Atomic number 64
• Atomic Weight: 157
• Solid state
• Appearance: Metallic, silver white
• Valencias: +3
• Melting point: 1312 ° C
• Boiling point: 3250 ° C

Gadolinium has few uses, the main one being magnetic industrial refrigeration, since it increases its magnetic properties at low temperatures; but as this type of coolers require the use of arsenic, they are not used in domestic refrigeration. In medicine it is used as a contrast medium for magnetic-nuclear resonance.

Terbium (Tb)

• Atomic number 65
• Atomic Weight: 159
• Solid state
• Appearance: Metallic, silver white
• Valencias: +4
• Melting point: 1356 ° C
• Boiling point: 3230 ° C

It was discovered in 1843 and isolated in 1905. It is very important in the electronics industry, as it is one of the elements used to make semiconductors. Other uses are to make fluorescent tubes and picture tubes. It is also used as a catalyst in fuel cells. Although it does not have biological functions, its inhalation or entry into the human body has toxic effects, mainly affecting the liver.

Dysprosium (Dy)

• Atomic number 66
• Atomic Weight: 162.5
• Solid state
• Appearance: Metallic, silver white
• Valencias: +2, +3
• Melting point: 1407 ° C
• Boiling point: 2567 ° C

It was discovered in 1843 and isolated in 1905. It is very important in the electronics industry, as it is one of the elements used to make semiconductors. Other uses are to make fluorescent tubes and picture tubes. It is also used as a catalyst in fuel cells. Although it does not have biological functions, its inhalation or entry into the human body has toxic effects, mainly affecting the liver.

Holmium (Ho)

• Atomic number 67
• Atomic Weight: 166
• Solid state
• Appearance: Metallic, silver white
• Valencias: +3
• Melting point: 1474 ° C
• Boiling point: 2700 ° C

It was discovered in 1878 and its name derives from the city of its discovery, Stockholm, in Latin, Holmia. It has almost no practical uses; however, it is used in some industries as a catalyst for chemical reactions, as well as for some electronic components. It is also used to change the frequency and intensity of the laser beam.

Erbium (Er)

• Atomic number 68
• Atomic Weight: 167
• Solid state
• Appearance: Metallic, silver white
• Valencias: +3
• Melting point: 1795 ° C
• Boiling point: 2863 ° C

It was discovered in 1843. It is used in the nuclear industry as a neutron buffer. In oxide form it is a colorant for crystals, which gives them a pink hue; These crystals are used in optics and jewelry. It is also used to make fiber optics.

Thulium (Tm)

• Atomic number 69
• Atomic Weight: 167
• Solid state
• Appearance: Metallic, silver white
• Valencias: +3
• Melting point: 1545 ° C
• Boiling point: 1947 ° C

It was discovered in 1879. Despite its low availability, due to its radioactive characteristics, its main use is as an X-ray source in portable equipment and for solid-state lasers.

Ytterbium (Yb)

• Atomic number 70
• Atomic Weight: 173
• Solid state
• Appearance: Metallic, silver white
• Valencias: +3
• Melting point: 824 ° C
• Boiling point: 1194 ° C

It was discovered in 1878 and isolated in 1907. Radioactive isotopes are used for portable X-ray equipment that works without electricity. It is also used to improve steel alloys and increase their resistance, a characteristic that is used in dentistry, due to the improvement of the mechanical properties of steel. It must be handled with care as it can cause irritation and burns. In addition, when reacting with air, it can cause an explosion or fire.

Lutetium (Lu)

• Atomic number 71
• Atomic Weight: 175
• Solid state
• Appearance: Metallic, silver white
• Valencias: +3
• Melting point: 1652 ° C
• Boiling point: 3402 ° C

It was discovered in 1907. It is the least abundant chemical element in the earth's crust. Despite its low availability, it is used for oil refining and as a catalyst for organic chemistry reactions. Some radioactive isotopes have also been tested for radiation therapy treatments.