Lanthanum oxide

Short description: Chemical compound

Lanthanum(III) oxide

Names
IUPAC name

Lanthanum(III) oxide

Other names

Lanthanum sesquioxide
Lanthana

Identifiers

CAS Number

* 1312-81-8 Y

3D model (JSmol)

* Interactive image

ChemSpider |

* 2529886 Y
* 133008 Y

EC Number |

* 215-200-5

PubChem CID

* 150906

RTECS number |

* OE5330000

UNII |

* 4QI5EL790W

InChI

* InChI=1S/2La.3O/q2*+3;3*-2 Y

Key: MRELNEQAGSRDBK-UHFFFAOYSA-N Y

SMILES

* [O-2].[O-2].[O-2].[La+3].[La+3]

Properties

Chemical formula

| La2O3
Molar mass | 325.808 g·mol−1
Appearance  | White powder, hygroscopic
Density | 6.51 g/cm3, solid
Melting point |  2,315 °C (4,199 °F; 2,588 K)
Boiling point |  4,200 °C (7,590 °F; 4,470 K)

Solubility in water

| Insoluble
Band gap | 4.3 eV

Magnetic susceptibility (χ)

| −78.0·10−6 cm3/mol
Structure

Crystal structure

| Hexagonal, hP5

Space group

| P-3m1, No. 164
Hazards
Main hazards | Irritant
Safety data sheet | External SDS
GHS pictograms | [1]
GHS Signal word | Warning[1]

GHS hazard statements

| H315, H319, H335[1]

GHS precautionary statements

| P261, P280, P301+310, P304+340, P305+351+338, P405, P501[1]
NFPA 704 (fire diamond)  |

~~W~~

Flash point | Non-flammable
Related compounds

Other anions

| Lanthanum(III) chloride

Other cations

| Cerium(III) oxide
Actinium(III) oxide

Related compounds

| Lanthanum aluminium oxide,
LaSrCoO4

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

N verify (what is YN ?)
Infobox references

Lanthanum(III) oxide, also known as lanthana, chemical formula La

3, is an inorganic compound containing the rare earth element lanthanum and oxygen. It is used in some ferroelectric materials, as a component of optical materials, and is a feedstock for certain catalysts, among other uses.

## Contents

* 1 Properties
* 2 Structure
* 3 Synthesis
* 4 Reactions
* 5 Potential applications
* 6 References

## Properties

3 powder

Lanthanum oxide is a white solid that is insoluble in water, but dissolves in acidic solutions. La

3 absorbs moisture from air, converts to lanthanum hydroxide.[2] Lanthanum oxide has p-type semiconducting properties and a band gap of approximately 5.8 eV.[3] Its average room temperature resistivity is 10 kΩ·cm, which decreases with an increase in temperature. La

3 has the lowest lattice energy of the rare earth oxides, with very high dielectric constant, ε = 27.

## Structure

At low temperatures, La

3 has an A-M

3 hexagonal crystal structure. The La3+ metal atoms are surrounded by a 7 coordinate group of O2− atoms, the oxygen ions are in an octahedral shape around the metal atom and there is one oxygen ion above one of the octahedral faces.[4] On the other hand, at high temperatures lanthanum oxide converts to a C-M

3 cubic crystal structure. The La3+ ion is surrounded by six O2− ions in a hexagonal configuration.[5][6]

## Synthesis

Lanthanum oxide can crystallize in at least three polymorphs.[2]

Hexagonal La

3 has been produced by spray pyrolysis of lanthanum chloride.[7]

2 LaCl
3 \+ 3 H
2O → La(OH)
3 \+ 3 HCl
2 La(OH)
3 → La

3 \+ 3 H

An alternative route to obtaining hexagonal La

3 involves precipitation of nominal La(OH)
3 from aqueous solution using a combination of 2.5% NH
3 and the surfactant sodium dodecyl sulfate followed by heating and stirring for 24 hours at 80 °C:

2 LaCl
3 \+ 3 H
2O + 3 NH
3 → La(OH)
3 \+ 3 [NH
4]Cl

Other routes include:

2 La

3 \+ 3 CO
2 → 2 La

3 \+ 3 CS

## Reactions

Lanthanum oxide is used as an additive to develop certain ferroelectric materials, such as La-doped bismuth titanate (Bi
4Ti

12 \- BLT). Lanthanum oxide is used in optical materials; often the optical glasses are doped with La

3 to improve the glass' refractive index, chemical durability, and mechanical strength.[8]

3 B

3 \+ La

3 → 2 La(BO

3[clarification needed]

The addition of the La

3 to the glass melt leads to a higher glass transition temperature from 658 °C to 679 °C. The addition also leads to a higher density, microhardness, and refractive index of the glass.

## Potential applications

Lanthanum oxide is most useful as a precursor to other lanthanum compounds.[9] Neither the oxide nor any of the derived materials enjoys substantial commercial value, unlike some of the other lanthanides. Many reports describe efforts toward practical applications of La

3, as described below.

3 forms glasses of high density, refractive index, and hardness. Together with oxides of tungsten, tantalum, and thorium, La

3 improves the resistance of the glass to attack by alkali. La

3 is an ingredient in some piezoelectric and thermoelectric materials.

3 has been examined for the oxidative coupling of methane.[10]

## References

1. ↑ 1.0 1.1 1.2 1.3 "Lanthanum Oxide". American Elements. https://www.americanelements.com/lanthanum-oxide-1312-81-8.
2. ↑ 2.0 2.1 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
3. ↑ Shang, G.; Peacock, P. W.; Robertson, J. (2004). "Stability and band offsets of nitrogenated high-dielectric-constant gate oxides". Applied Physics Letters 84 (1): 106–108. doi:10.1063/1.1638896. Bibcode: 2004ApPhL..84..106S.
4. ↑ Wells, A.F. (1984). Structural Inorganic Chemistry. Oxford: Clarendon Press. p. 546.
5. ↑ Wyckoff, R. W.G. (1963). Crystal Structures: Inorganic Compounds RXn, RnMX2, RnMX3. New York: Interscience Publishers.
6. ↑ Adachi, Gin-ya; Imanaka, Nobuhito (1998). "The Binary Rare Earth Oxides". Chemical Reviews 98 (4): 1479–1514. doi:10.1021/cr940055h. PMID 11848940.
7. ↑ Kale, S.S.; Jadhav, K.R.; Patil, P.S.; Gujar, T.P.; Lokhande, C.D. (2005). "Characterizations of spray-deposited lanthanum oxide (La2O3) thin films". Materials Letters 59 (24–25): 3007–3009. doi:10.1016/j.matlet.2005.02.091.
8. ↑ Vinogradova, N. N.; Dmitruk, L. N.; Petrova, O. B. (2004). "Glass Transition and Crystallization of Glasses Based on Rare-Earth Borates". Glass Physics and Chemistry 30: 1–5. doi:10.1023/B:GPAC.0000016391.83527.44.
9. ↑ "Lanthanum has also found modest uses." Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 946. ISBN 978-0-08-037941-8.
10. ↑ Manoilova, O.V. (2004). "Surface acidity and basicity of La2O3, LaOCl, and LaCl3 characterized by IR spectroscopy, TPD, and DFT calculations". J. Phys. Chem. B 108 (40): 15770–15781. doi:10.1021/jp040311m.

* v
* t
* e

Lanthanum compounds

* LaB6
* LaBr3
* LaC2
* LaCl3
* La2(CO3)3
* LaH10
* LaF3
* La2O3
* La(OH)3

* v
* t
* e

Oxides

Mixed oxidation states|

* Antimony tetroxide (Sb2O4)
* Cobalt(II,III) oxide (Co3O4)
* Europium(II,III) oxide (Eu3O4)
* Iron(II,III) oxide (Fe<sub>3O4)
* Lead(II,IV) oxide (Pb3O4)
* Manganese(II,III) oxide (Mn3O4)
* Silver(I,III) oxide (Ag2O2)
* Triuranium octoxide (U3O8)
* Carbon suboxide (C3O2)
* Mellitic anhydride (C12O9)
* [[Chemistry:Praseodymium(III,IV) Praseodymium(III,IV) oxide]] (Pr6O11)
* Terbium(III,IV) oxide (Tb4O7)

+1 oxidation state|

* Copper(I) oxide (Cu<sub>2O)
* Caesium oxide (Cs2O)
* Dicarbon monoxide (C2O)
* Dichlorine monoxide (Cl2O)
* Gallium(I) oxide (Ga2O)
* Lithium oxide (Li2O)
* Potassium oxide (K2O)
* Rubidium oxide (Rb2O)
* Silver oxide (Ag2O)
* Thallium(I) oxide (Tl2O)
* Sodium oxide (Na2O)
* Water (hydrogen oxide) (H2O)

+2 oxidation state|

* Aluminium(II) oxide (AlO)
* Barium oxide (BaO)
* Beryllium oxide (BeO)
* Cadmium oxide (CdO)
* Calcium oxide (CaO)
* Carbon monoxide (CO)
* Chromium(II) oxide (CrO)
* Cobalt(II) oxide (CoO)
* Copper(II) oxide (CuO)
* Europium(II) oxide (EuO)
* Germanium monoxide (GeO))
* Iron(II) oxide (FeO)
* Lead(II) oxide (PbO)
* Magnesium oxide (MgO)
* Manganese(II) oxide (MnO)
* Mercury(II) oxide (HgO)
* Nickel(II) oxide (NiO)
* Nitric oxide (NO)
* Palladium(II) oxide (PdO)
* Silicon monoxide (SiO)
* Strontium oxide (SrO)
* Sulfur monoxide (SO)
* Disulfur dioxide (S2O2)
* Thorium monoxide (ThO)
* Tin(II) oxide (SnO)
* Titanium(II) oxide (TiO)
* Vanadium(II) oxide (VO)
* Zinc oxide (ZnO)

+3 oxidation state|

* Aluminium oxide (Al<sub>2O3)
* Antimony trioxide (Sb2O3)
* Arsenic trioxide (As2O3)
* Bismuth(III) oxide (Bi2O3)
* Boron trioxide (B2O3)
* Cerium(III) oxide (Ce2O3)
* Dibromine trioxide (Br2O3)
* Chromium(III) oxide (Cr2O3)
* Dinitrogen trioxide (N2O3)
* Dysprosium(III) oxide (Dy2O3)
* Erbium(III) oxide (Er2O3)
* Europium(III) oxide (Eu2O3)
* Gadolinium(III) oxide (Gd2O3)
* Gallium(III) oxide (Ga2O3)
* Holmium(III) oxide (Ho2O3)
* Indium(III) oxide (In<sub>2O3)
* Iron(III) oxide (Fe2O3)
* Lanthanum oxide (La2O3)
* Lutetium(III) oxide (Lu2O3)
* Manganese(III) oxide (Mn2O3)
* Neodymium(III) oxide (Nd2O3)
* Nickel(III) oxide (Ni2O3)
* Phosphorus trioxide (P4O6)
* Praseodymium(III) oxide (Pr2O3)
* Promethium(III) oxide (Pm2O3)
* Rhodium(III) oxide (Rh2O3)
* [[Chemistry:Samarium(III) Samarium(III) oxide]] (Sm2O3)
* Scandium oxide (Sc2O3)
* Terbium(III) oxide (Tb2O3)
* Thallium(III) oxide (Tl2O3)
* Thulium(III) oxide (Tm2O3)
* Titanium(III) oxide (Ti2O3)
* Tungsten(III) oxide (W2O3)
* Vanadium(III) oxide (V2O3)
* Ytterbium(III) oxide (Yb2O3)
* Yttrium(III) oxide (Y2O3)

+4 oxidation state|

* Americium dioxide (AmO2)
* Carbon dioxide (CO2)
* Carbon trioxide (CO3)
* Cerium(IV) oxide (CeO2)
* Chlorine dioxide (ClO2)
* Chromium(IV) oxide (CrO<sub>2)
* Dinitrogen tetroxide (N2O4)
* Germanium dioxide (GeO<sub>2)
* [[Chemistry:Hafnium(IV) Hafnium(IV) oxide]] (HfO2)
* Lead dioxide (PbO2)
* Manganese dioxide (MnO2)
* Neptunium(IV) oxide (NpO2)
* Nitrogen dioxide (NO2)
* Osmium dioxide (OsO2)
* Plutonium(IV) oxide (PuO2)
* Praseodymium(IV) oxide (PrO2)
* Protactinium(IV) oxide (PaO2)
* Rhodium(IV) oxide (RhO2)
* Ruthenium(IV) oxide (RuO<sub>2)
* Selenium dioxide (SeO2)
* Silicon dioxide (SiO2)
* Sulfur dioxide (SO2)
* Tellurium dioxide (TeO<sub>2)
* [[Chemistry:Terbium(IV) Terbium(IV) oxide]] (TbO2)
* Thorium dioxide (ThO2)
* Tin dioxide (SnO2)
* Titanium dioxide (TiO<sub>2)
* Tungsten(IV) oxide (WO2)
* Uranium dioxide (UO2)
* Vanadium(IV) oxide (VO2)
* Zirconium dioxide (ZrO2)

+5 oxidation state|

* Antimony pentoxide (Sb2O5)
* Arsenic pentoxide (As2O5)
* Dinitrogen pentoxide (N2O5)
* Niobium pentoxide (Nb2O5)
* Phosphorus pentoxide (P2O5)
* Protactinium(V) oxide (Pa2O5)
* Tantalum pentoxide (Ta2O5)
* Vanadium(V) oxide (V2O5)

+6 oxidation state|

* Chromium trioxide (CrO3)
* Molybdenum trioxide (MoO3)
* Rhenium trioxide (ReO3)
* Selenium trioxide (SeO3)
* Sulfur trioxide (SO3)
* Tellurium trioxide (TeO3)
* Tungsten trioxide (WO3)
* Uranium trioxide (UO3)
* Xenon trioxide (XeO3)
* Iridium trioxide (IrO3)

+7 oxidation state|

* Dichlorine heptoxide (Cl2O7)
* Manganese heptoxide (Mn2O7)
* [[Chemistry:Rhenium(VII) Rhenium(VII) oxide]] (Re2O7)
* Technetium(VII) oxide (Tc2O7)

+8 oxidation state|

* Osmium tetroxide (OsO4)
* Ruthenium tetroxide (RuO4)
* Xenon tetroxide (XeO4)
* Iridium tetroxide (IrO4)
* Hassium tetroxide (HsO4)

Related|

* Oxocarbon
* Suboxide
* Oxyanion
* Ozonide
* Peroxide
* Superoxide

Oxides are sorted by oxidation state. Category:Oxides

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*[CID]: Compound ID
*[H315]: Causes skin irritation
*[H319]: Causes serious eye irritation
*[H335]: May cause respiratory irritation
*[P261]: Avoid breathing dust/fume/gas/mist/vapours/spray
*[P280]: Wear protective gloves/protective clothing/eye protection/face protection
*[P301+310]: IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician
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*[P501]: Dispose of contents/container to …
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