Erbium oxide (CAS NO.12645-29-3) was partially isolated by Carl Gustaf Mosander in 1843, and first obtained in pure form in 1905 by Georges Urbain and Charles James.

The Erbium oxide, with the CAS registry number 12645-29-3, has the systematic name of erbium(+3) cation; oxygen(-2) anion. It is a is a compound of erbium with the appearance of pink solid. It is also called Erbium trioxide. And the molecular formula of this chemical is Er₂O₃.

The physical properties of Erbium oxide are as following: (1)#H bond acceptors: 1; (2)#H bond donors: 0; (3)#Freely Rotating Bonds: 0; (4)Polar Surface Area: 0 Å².

Uses of Erbium oxide: It is used as a colouring for glasses and a dopant for optical fibres and optical amplifiers. It can be also used as a burnable neutron poison for nuclear fuel, and it can also react with acids to give the corresponding erbium(III) salts:
Er₂O₃ + 6HCl → 2ErCl₃ + 3H₂O

You can still convert the following datas into molecular structure:
(1)SMILES: [Er+3].[Er+3].[O-2].[O-2].[O-2]
(2)InChI: InChI=1/2Er.3O/q2*+3;3*-2
(3)InChIKey: ZXGIFJXRQHZCGJ-UHFFFAOYAC