Erbium

Symbol: Er
Atomic number: 68
Category: lanthanides
Group: n/a
Period: 6
Block: f
Atomic weight: 167.259 g/mol
Electrons per shell: 2, 8, 18, 30, 8, 2
CAS number: 7440-52-0
Phase: solid
Density: 9.066 kg/dm³ (near room temperature)
Melting point: 1802 K (1529 °C, 2784 °F)
Boiling point: 3141 K (2868 °C, 5194 °F)
Crystal structure: hexagonal
Oxidation states: 3
Electronegativity: 1.24 (Pauling scale)
Name's origin: Ytterby
Name's meaning: the village where the element was found
Facts:
- is a rare, silvery, white metallic lanthanide which is solid in its normal state
- is malleable (or easily shaped), soft yet stable in air, and does not oxidize as quickly as some other rare-earth metals
- its salts are rose-colored, and the element has characteristic sharp absorption spectra bands in visible light, ultraviolet, and near infrared
- does not play any known biological role, but is thought by some to be able to stimulate metabolism
- is commonly used as a photographic filter, and because of its resilience it is useful as a metallurgical additive
- its estimated abundance in the Earth's crust is 1.3 mg/kg
- the mineral gadolinite was spearated into three fractions which was called yttria, erbia, and terbia - erbia and terbia, however, were confused at this time, and after 1860, terbia was renamed erbia and after 1877 what had been known as erbia was renamed terbia
- is never found as a free element in nature but is found bound in monazite sand ores
- has historically been very difficult and expensive to separate rare earths from each other in their ores but ion-exchange production techniques developed in the late 20th century have greatly brought down the cost of production of all rare-earth metals and their chemical compounds
- metallic erbium in dust form presents a fire and explosion hazard