Gallium (III) oxide

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Crystal structure
Crystal structure of β-gallium oxide
__ Ga 3+      __ O 2−
General
Surname Gallium (III) oxide
other names
  • Gallium oxide (ambiguous)
  • Digallium trioxide
Ratio formula Ga 2 O 3
Brief description

white, crystalline solid

External identifiers / databases
CAS number 12024-21-4
EC number 234-691-7
ECHA InfoCard 100.031.525
PubChem 5139834
Wikidata Q419487
properties
Molar mass 187.5 g mol −1
Physical state

firmly

density

5.88 g cm −3

Melting point

1740 ° C

solubility
  • almost insoluble in water
  • soluble in acids
safety instructions
GHS labeling of hazardous substances
no GHS pictograms
H and P phrases H: no H-phrases
P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Gallium (III) oxide is a chemical compound of gallium and is one of the oxides . The colorless, crystalline solid occurs in five modifications .

Extraction and presentation

Gallium (III) oxide can be obtained by dehydrating gallium hydroxide at 500 ° C.

An alternative is the decomposition of gallium nitrate at 200 ° C. The two ways of representation lead to different modifications, which are converted into the most stable β-modification at higher temperatures.

properties

The modifications of gallium (III) oxide are designated with the Greek letters α to ε. The most stable is the monoclinic β modification. If gallium hydroxide is dehydrated, the γ-modification forms first, the structure of which is a spinel structure with gallium defects. With prolonged heating, this changes into the α-Ga 2 O 3 modification with a corundum structure and finally into β-Ga 2 O 3 .

In the reaction pathway via gallium nitrate, the bixbyite- like δ-modification is initially formed , which also converts to β-Ga 2 O 3 when heated more strongly via the orthorhombic ε phase .

Several gallium oxide modifications show photocatalytic activity in the decomposition of aromatic compounds such as benzene or toluene . It is higher than that of the frequently used titanium (IV) oxide .

use

Gallium (III) oxide is the starting material for the production of gadolinium gallium garnet for magnetic bubble storage .

Individual evidence

  1. ↑ a b digallium trioxide at webelements.com .
  2. ↑ a b c d e f data sheet Gallium (III) oxide, Puratronic®, 99.999% (metals basis) from AlfaAesar, accessed on December 23, 2019 ( PDF )(JavaScript required) .
  3. ^ A b c d A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 1196.
  4. ^ A b S. Yoshioka, H. Hayashi, A. Kuwabara, F. Oba, K. Matsunaga, I Tanaka: Structures and energetics of Ga 2 O 3 polymorphs. In: J. Phys .: Condens. Matter . 2007, 19, pp. 346211-22, doi : 10.1088 / 0953-8984 / 19/34/346211 .
  5. ↑ Yidong Hou, Ling Wu, Xinchen Wang, Zhengxin Ding, Zhaohui Li, Xianzhi Fu: Photocatalytic performance of α-, β-, and γ-Ga 2 O 3 for the destruction of volatile aromatic pollutants in air. In: Journal of Catalysis. 2007, 250, 1, pp. 12-18, doi : 10.1016 / j.jcat.2007.05.012 .
  6. ↑ Entry on gallium compounds. In: Römpp Online . Georg Thieme Verlag, accessed on June 13, 2014.