Holmium oxide

Holmium(III) oxide

Names
IUPAC name Holmium(III) oxide
Other names Holmium oxide, Holmia
Identifiers
CAS Number	12055-62-8 Y
3D model (JSmol)	Interactive image Interactive image
ChemSpider	3441223 Y
ECHA InfoCard	100.031.820
EC Number	235-015-3
PubChem CID	4232365
InChI InChI=1S/2Ho.3O Y Key: JYTUFVYWTIKZGR-UHFFFAOYSA-N Y InChI=1/2Ho.3O/rHo2O3/c3-1-5-2-4 Key: JYTUFVYWTIKZGR-VLHOCPAZAL
SMILES [O][Ho]O[Ho][O] O=[Ho]O[Ho]=O
Properties
Chemical formula	Ho2O3
Molar mass	377.86 g·mol−1
Appearance	Pale yellow, opaque powder.
Density	8.41 g cm−3
Melting point	2,415 °C (4,379 °F; 2,688 K)
Boiling point	3,900 °C (7,050 °F; 4,170 K)
Band gap	5.3 eV
Magnetic susceptibility (χ)	+88,100·10−6 cm3/mol
Refractive index (nD)	1.8
Structure
Crystal structure	Cubic, cI80
Space group	Ia-3, No. 206
Thermochemistry
Specific heat capacity (C)	115.0 J mol−1 K−1
Std molar entropy (So298)	158.2 J mol−1 K−1
Std enthalpy of formation (ΔfHo298)	-1880.7 kJ mol−1
Hazards
Safety data sheet	External MSDS
S-phrases (outdated)	S22, S24/25
Related compounds
Other anions	Holmium(III) chloride
Other cations	Dysprosium(III) oxide Erbium(III) oxide
Related compounds	Bismuth(III) oxide Europium(III) oxide Gold(III) oxide Lanthanum(III) oxide Lutetium(III) oxide Praseodymium(III) oxide Promethium(III) oxide Terbium(III) oxide Thallium(III) oxide Thulium(III) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Europium(III) oxide
Gold(III) oxide
Lanthanum(III) oxide
Lutetium(III) oxide
Praseodymium(III) oxide
Promethium(III) oxide
Terbium(III) oxide
Thallium(III) oxide
Thulium(III) oxide

Holmium(III) oxide, or holmium oxide is a chemical compound of a rare-earth element holmium and oxygen with the formula Ho₂O₃. Together with dysprosium(III) oxide (Dy₂O₃) holmium oxide is one of the most powerfully paramagnetic substances known. The oxide, also called holmia, occurs as a component of the related erbium oxide mineral called erbia. Typically the oxides of the trivalent lanthanides coexist in nature and separation of these components requires specialized methods. Holmium oxide is used in making specialty colored glasses. Glass containing holmium oxide and holmium oxide solutions have a series of sharp optical absorption peaks in the visible spectral range. They are therefore traditionally used as a convenient calibration standard for optical spectrophotometers.

Holmium oxide has some fairly dramatic color changes depending on the lighting conditions. In daylight, it is a tannish yellow color. Under trichromatic light, it is a fiery orange red, almost indistinguishable from the way erbium oxide looks under this same lighting. This is related to the sharp emission bands of the phosphors. Holmium oxide has a wide band gap of 5.3 eV and thus should appear colorless. The yellow color originates from abundant lattice defects (such as oxygen vacancies) and is related to internal transitions at the Ho³⁺ ions.