Lanthanum oxide

Crystal structure
__ La 3+      __ O 2−
General
Surname	Lanthanum oxide
other names	Lanthanum sesquioxide Dilanthanum trioxide Lanthanum (III) oxide
Ratio formula	La 2 O 3
Brief description	white, odorless solid
External identifiers / databases
CAS number 1312-81-8 EC number 215-200-5 ECHA InfoCard 100,013,819 PubChem 150906 Wikidata Q417250
properties
Molar mass	325.81 g mol −1
Physical state	firmly
density	6.51 g cm −3
Melting point	2315 ° C
boiling point	4200 ° C
solubility	almost insoluble in water
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
Toxicological data	9970 mg kg −1 ( LD 50 ,  rat ,  oral )
Thermodynamic properties
ΔH f 0	−1794.9 kJ / mol
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Lanthanum oxide is the oxide of the rare earth metal lanthanum .

Occurrence

Lanthanum oxide is a compound obtained from lanthanum minerals such as B .: Monazite , Cerit , Bastnäsit , Cheralith and Samarskit is produced.

properties

Lanthana is a white powder. Similar to calcium oxide, it reacts strongly exothermically with water to form lanthanum hydroxide .

${\displaystyle \mathrm {La_{2}O_{3}+3\ H_{2}O\longrightarrow 2\ La(OH)_{3}} }$

• 

  La ₂ O ₃ powder

• 

  Lanthanum oxide

presentation

After the laborious separation of the other lanthanides from their ores, lanthanum oxalate is finally obtained, which is then burned to lanthanum oxide La ₂ O ₃ .

${\displaystyle \mathrm {2\ La_{2}(C_{2}O_{4})_{3}+3\ O_{2}\longrightarrow 2\ La_{2}O_{3}+12\ CO_{2}} }$

use

• Lanthanum oxide is mainly used to produce the pure metal lanthanum . For this purpose, it is converted to lanthanum fluoride using hydrogen fluoride (HF) or, at higher temperatures, to anhydrous lanthanum chloride using chlorine . Both halides can then be metallothermally reduced to the metal using calcium or magnesium .
• Highly pure lanthanum oxide is used in the glass industry to produce high-quality glasses for optics , e.g. B. for camera lenses used. The cameras of the first two Mars Rover had, for example, at least one lens from the Schott -Lanthanglas LaFN21 was made.
• As a La-Pb-Mn catalyst , it is used to purify exhaust gas for internal combustion engines, as it not only oxidizes carbon monoxide to carbon dioxide, but also reduces nitrogen oxides to nitrogen .
• It is also used to make tungsten electrodes for welding .
• Otherwise, lanthanum oxide is used to produce other lanthanum compounds.

Individual evidence

1. ↑ ^{a b c d e f g h} Entry on lanthanum (III) oxide in the GESTIS substance database of the IFA , accessed on December 21, 2019(JavaScript required) .
2. ↑ Bailar et al .: Comprehensive Inorganic Chemistry. 1973, p. 89.
3. ↑ NASA: Optical Designs for the Mars '03 Rover Cameras ( Memento of the original from May 27, 2010 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (accessed on April 21, 2011; PDF; 1.3 MB)