Atomic Number: 68
Atomic Weight: 167.259
Melting Point: 1802 K (1529°C or 2784°F)
Boiling Point: 3141 K (2868°C or 5194°F)
Density: 9.07 grams per cubic centimeter
Phase at Room Temperature: Solid
Element Classification: Metal
Period Number: 6
Group Number: none
Group Name: Lanthanide
Erbium has six stable isotopes but only Er-168 appears to have a well established application. Er-168 is used for the production of Er-169 which is used in form of citrate for the treatment of rheumatoid arthritis.