ElementsWhat are the lanthanides?
The lanthanides are the fifteen elements from lanthanum to lutetium. They are usually drawn in a separate row below the main table to keep it narrow. Together with scandium and yttrium they are called rare earth elements. Most are not truly rare, but they occur mixed together and are hard to separate. They are soft, silvery metals with very similar chemistry. Their special magnetic and light-giving properties make them important for magnets, screens, lasers and green energy.
The family in numbers
Melting points in this family run from 797.9 °C (cerium) to 1,663 °C (lutetium). Among its solid members, the least dense is europium (5.24 g/cm³) and the densest is lutetium (9.84 g/cm³). The most recently discovered member is promethium (1945).
Why they are so alike
Across most rows of the table each new element adds an electron to the outer shell, and the chemistry changes step by step. Across the lanthanides the added electrons go into an inner shell, two layers down, while the outer electrons stay the same. Chemistry is decided by the outer electrons, so all fifteen behave almost identically. That is why they are found together in the same minerals and why separating one from another is slow and costly. The atoms also shrink slightly from lanthanum to lutetium, an effect called the lanthanide contraction.
Where you meet them
The lanthanides are hidden inside modern technology. Neodymium makes the strongest permanent magnets known, used in headphones, hard disks, electric vehicle motors and wind turbines. Europium and terbium give the red and green light of screens and energy-saving lamps. Cerium is in the flints of lighters and in the powder used to polish glass, and lanthanum is in camera lenses. Promethium is the odd one out: it has no stable form and is radioactive.
In India
The beach sands of Kerala, Tamil Nadu and Odisha contain monazite, a heavy mineral that holds lanthanides together with thorium.
All lanthanides compared
| No. | Symbol | Name | Atomic mass | State | Melts at | Boils at | Density g/cm³ | Discovered |
|---|---|---|---|---|---|---|---|---|
| 57 | La | Lanthanum | 138.9055 | Solid | 917.9 °C | 3,464 °C | 6.15 | 1839 |
| 58 | Ce | Cerium | 140.116 | Solid | 797.9 °C | 3,424 °C | 6.77 | 1803 |
| 59 | Pr | Praseodymium | 140.90766 | Solid | 930.9 °C | 3,520 °C | 6.77 | 1885 |
| 60 | Nd | Neodymium | 144.24 | Solid | 1,021 °C | 3,074 °C | 7.01 | 1885 |
| 61 | Pm | Promethium | 144.91276 | Solid | 1,042 °C | 3,000 °C | 7.26 | 1945 |
| 62 | Sm | Samarium | 150.4 | Solid | 1,074 °C | 1,794 °C | 7.52 | 1879 |
| 63 | Eu | Europium | 151.964 | Solid | 821.9 °C | 1,529 °C | 5.24 | 1901 |
| 64 | Gd | Gadolinium | 157.25 | Solid | 1,313 °C | 3,273 °C | 7.9 | 1880 |
| 65 | Tb | Terbium | 158.92535 | Solid | 1,356 °C | 3,230 °C | 8.23 | 1843 |
| 66 | Dy | Dysprosium | 162.500 | Solid | 1,412 °C | 2,567 °C | 8.55 | 1886 |
| 67 | Ho | Holmium | 164.93033 | Solid | 1,474 °C | 2,700 °C | 8.8 | 1878 |
| 68 | Er | Erbium | 167.26 | Solid | 1,529 °C | 2,868 °C | 9.07 | 1843 |
| 69 | Tm | Thulium | 168.93422 | Solid | 1,545 °C | 1,950 °C | 9.32 | 1879 |
| 70 | Yb | Ytterbium | 173.05 | Solid | 818.9 °C | 1,196 °C | 6.9 | 1878 |
| 71 | Lu | Lutetium | 174.9667 | Solid | 1,663 °C | 3,402 °C | 9.84 | 1907 |
Other families: alkali metals, alkaline earth metals, transition metals, post-transition metals, metalloids, nonmetals, halogens, noble gases, actinides.