Alumina hydroxide

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Structural formula
No drawing available
General
Surname Alumina hydroxide
other names
  • Aluminum metahydroxide
  • Alumina hydrate
Molecular formula AlO (OH)
Brief description

colorless solid

External identifiers / databases
CAS number 24623-77-6
EC number 246-368-8
ECHA InfoCard 100.042.138
PubChem 32524
Wikidata Q4291506
properties
Molar mass 59.99 g mol −1
Physical state

firmly

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 .

Aluminum oxide hydroxide is an inorganic chemical compound of aluminum from the group of hydroxides .

Occurrence

Aluminum oxide hydroxide occurs naturally in the form of the orthorhombic minerals diaspore (α-AlO (OH)) and boehmite (γ-AlO (OH)), as well as (contaminated with aluminum hydroxide , iron hydroxides , aluminosilicates , titanium oxides and others) in bauxite .

Extraction and presentation

Y-aluminum oxide hydroxide can be obtained artificially hydrothermally from hydrargillite or amorphous aluminum hydroxides in an autoclave by heating it to 300 ° C for two hours. It is hydrothermally converted into α-aluminum oxide hydroxide by heating for several days in 0.4% sodium hydroxide solution at 380 ° C. and 500 bar.

properties

Alumina hydroxide is a colorless solid. In crystallized alumina hydroxide, aluminum is octahedral surrounded by both OH groups and oxygen atoms. In the α-aluminum oxide hydroxide structure, the oxygen atoms are hexagonally densely packed. The aluminum ions each occupy half of the octahedral gaps between the densely packed oxygen atom layers. In y-aluminum oxide hydroxide, layer-like areas with the most dense cubic oxygen atom packing alternate with those without a dense oxygen atom packing.

use

Alumina hydroxide can be used as a flame retardant .

Individual evidence

  1. ↑ a b c d e Entry on aluminum oxide hydroxide in the GESTIS substance database of the IFA , accessed on March 5, 2019(JavaScript required) .
  2. ↑ a b c Egon Wiberg, A. .F. Holleman: Basics and main group elements . Walter de Gruyter GmbH & Co KG, 2016, ISBN 978-3-11-049585-0 , p. 1355 ( limited preview in Google Book search).
  3. ↑ Andreas Giessmann: Substrate and Textile Coating Practical knowledge for coating and lamination technologies . Springer-Verlag, 2009, ISBN 978-3-642-01417-8 , pp. 187 ( limited preview in Google Book search).