Erbium is a chemical element with the symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements.
Phase at STP： solid
Melting point： 1802 K (1529 °C, 2784 °F)
Boiling point： 3141 K (2868 °C, 5194 °F)
Density (near r.t.)： 9.066 g/cm3
when liquid (at m.p.)： 8.86 g/cm3
Heat of fusion： 19.90 kJ/mol
Heat of vaporization： 280 kJ/mol
Molar heat capacity： 28.12 J/(mol·K)
Erbium’s principal uses involve its pink-colored Er3+ ions, which have optical fluorescent properties particularly useful in certain laser applications. Erbium-doped glasses or crystals can be used as optical amplification media, where Er3+ ions are optically pumped at around 980 or 1480 nm and then radiate light at 1530 nm in stimulated emission. This process results in an unusually mechanically simple laser optical amplifier for signals transmitted by fiber optics. The 1550 nm wavelength is especially important for optical communications because standard single mode optical fibers have minimal loss at this particular wavelength.