Lanthanides

Lanthanides are a set of 15 naturally occurring metallic elements, whose atomic numbers fall between 57 (lanthanum) and 71 (lutetium). These elements all have their 4f sublevel filled. Lanthanides exhibit similarities in physical and chemical properties, and they have many industrial uses.

List of Lanthanides

The lanthanides are located in block 5d of the periodic table. The first 5d transition element is either lanthanum or lutetium, depending on how you interpret the periodic trends of the elements. Sometimes only the lanthanides, and not the actinides, are classified as rare earths; however, even the scarce rare earths (e.g., europium, lutetium) are more common than platinum-group metals.

Several of these lanthanides form during fission processes with uranium and plutonium materials.

Common Properties of the Lanthanides

Lanthanides share the following common properties:

  • Tarnishes in the air, forming its oxides.
  • Soft metals. Hardness increases somewhat as the atomic number rises.
  • Each lanthanide 3+ ion’s radius decreases from left to right across the period (increasing atomic number). This is known as ‘lanthanide shrinkage.’
  • Melting points and boiling points are high.
  • They’re very reactive.
  • React with water to release hydrogen (H2) gradually, but rapidly after heating
  • React with H+ (dilute acid) to release H2 (rapidly at room temperature).
  • React in an exothermic reaction with H2.
  • Burn easily in air.
  • They are strong reducing agents.
  • Their compounds are generally ionic.
  • At elevated temperatures, many rare earths ignite and burn vigorously.
  • Most rare earth compounds are strongly paramagnetic.
  • Many rare earth compounds fluoresce strongly under ultraviolet light.
  • Lanthanide ions tend to be pale colors, resulting from weak, narrow, forbidden f x f optical transitions.
  • The magnetic moments of the lanthanide and iron ions oppose each other.
  • The lanthanides react readily with most nonmetals and form binaries on heating with most nonmetals.

Lanthanum (La)

Lanthanum is a chemical element with atomic number 57 in the periodic table. In Earth’s crust, element 57 is mainly contained as the ferromagnetic metal cobalt (Co). This rare-earth metal is classified as a member of the lanthanides family of chemical elements.  As a transition metal, lanthanum is a chemical that has three allotropic forms, … Read more

Cerium (Ce)

Cerium is a chemical element with an atomic number of 58 in the periodic table of elements. It’s the most abundant rare-earth metal that is found in Earth’s crust. Being a member of the lanthanides family of periodic table elements, this transitional element from period 6 in the periodic table of elements has four valence … Read more

Praseodymium (Pr)

Praseodymium is a chemical element with the atomic number 59 in the periodic table. It occurs naturally in Earth’s crust with an abundance of 9.5 parts per million. However, praseodymium can be rarely found in its pure, elemental form.  Being a member of the lanthanides family of elements, this highly reactive chemical element is a … Read more

Neodymium (Nd)

Neodymium is a chemical element with the atomic number 60 in the periodic table. Despite being classified as a rare-earth element, neodymium is widely distributed in Earth’s crust. It mainly occurs in the mineral ores. As a member of the lanthanide series of periodic table elements, this rare-earth metal has three valence electrons that help … Read more

Promethium (Pm)

Promethium is a chemical element with the atomic number 61 in the periodic table. Although it’s an artificially produced substance that cannot be found in Earth’s crust, promethium can also occur in trace amounts in the uranium ores.  Element 61 is classified as a member of the lanthanides family of the periodic table. This highly … Read more

Samarium (Sm)

Samarium is a chemical element with the atomic number 62 in the periodic table. With an abundance of 6 parts per million, it’s the 40th most abundant chemical element in Earth’s crust.  Being a member of the lanthanides family of periodic table elements, this rare-earth element is a divalent substance that’s widely used in the … Read more

Europium (Eu)

Europium is a chemical element with an atomic number of 63 in the periodic table of elements. It’s one of the least abundant rare-earth elements that can be traced in Earth’s crust. Being a member of the lanthanides family of periodic table elements, europium is a divalent chemical element that makes it one of the … Read more

Gadolinium (Gd)

Gadolinium (Gd) is a chemical element with an atomic number of 64 in the periodic table of elements. There’s about 6.2 mg/kg of this soft metal occurring in Earth’s crust. This makes gadolinium one of the most abundant rare-earth elements found in nature. Being a member of the lanthanides family of periodic table elements, gadolinium … Read more

Terbium (Tb)

Terbium is a chemical element with the atomic number 65 in the periodic table. It’s one of the least plentiful rare-earth metals that occur in Earth’s crust. Located between the elements gadolinium and dysprosium, terbium is classified as a member of the lanthanide series of the periodic table. This rare-earth metal has three valence electrons … Read more

Dysprosium (Dy)

Dysprosium is a chemical element with an atomic number of 66 in the periodic table of elements. It’s one of the more abundant lanthanide elements found in Earth’s crust, in a concentration of 3 parts per million. Still, it never occurs in its free elemental form. Classified in the heavy rare-earth elements group (HREE), this … Read more