Lithium aluminate

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Crystal structure
Crystal structure of lithium aluminate
__ Li +      __ Al 3+      __ O 2−
General
Surname Lithium aluminate
other names
  • Aluminum lithium oxide
  • Lithium alumina
  • Lithium metaluminate
Ratio formula LiAlO 2
Brief description

white solid

External identifiers / databases
CAS number 12003-67-7
EC number 234-434-9
ECHA InfoCard 100.031.291
PubChem 123268
Wikidata Q2190661
properties
Molar mass 65.92 g mol −1
Physical state

firmly

density
  • 3.61 g cm −3 (α)
  • 2.615 g cm −3 (γ)
Melting point

1610 ° C

solubility

almost insoluble in water

safety instructions
GHS labeling of hazardous substances
07 - Warning

Caution

H and P phrases H: 315-319-335
P: 261-305 + 351 + 338
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Lithium aluminate is an inorganic chemical compound of lithium from the group of aluminates . In the Li 2 O-Al 2 O 3 system there are two other stable lithium aluminates in addition to the LiAlO 2 described here with Li 5 AlO4 and LiAl 5 O 8 .

Extraction and presentation

Lithium aluminate can be obtained by reacting aluminum oxide with lithium carbonate at 870–970 K. The γ-phase can be irreversibly obtained by sintering the α-phase at 1350 ° C. Synthesis by sol-gel synthesis from aluminum chloride and lithium carbonate or by synthesis from a lithium hydroxide solution with boehmite and subsequent evaporation and calcination at 900 ° C. is also possible.

properties

Lithium aluminate is a white solid that is insoluble in water. In the normal γ-phase it has a tetragonal crystal structure and the space group P 4 1 2 1 2 (space group no. 92) . There is also an α-modification with a trigonal crystal structure with the space group R 3 m (space group no. 166) , which has a crystal structure similar to that of sodium hydrogen fluoride. Template: room group / 92 Template: room group / 166

use

Lithium aluminate is used in carbonate fuel cells . It is also used as a substrate for gallium nitride semiconductors.

Individual evidence

  1. ↑ a b c d e R. Blachnik: Pocket book for chemists and physicists Volume 3: Elements, inorganic compounds and materials, minerals . Springer-Verlag, 2013, ISBN 978-3-642-58842-6 , pp. 530 ( limited preview in Google Book search).
  2. ↑ a b c d data sheet Lithium aluminate from Sigma-Aldrich , accessed on May 25, 2017 ( PDF ).
  3. ^ A b James F. Shackelford, Robert H. Doremus: Ceramic and Glass Materials Structure, Properties and Processing . Springer Science & Business Media, 2008, ISBN 978-0-387-73362-3 , pp. 59 ( limited preview in Google Book search).
  4. ↑ Jian CHENG, Liejin GUO, Shisen XU, Ruiyun ZHANG, Chen LI: Submicron γ-LiAlO 2 Powder Synthesized from Boehmite. In: Chinese Journal of Chemical Engineering. 20, 2012, p. 776, doi : 10.1016 / s1004-9541 ​​(11) 60248-6 .
  5. ↑ M. Marezio: The crystal structure and anomalous dispersion of γ-LiAlO 2 . In: Acta Crystallographica. 19, p. 396, doi : 10.1107 / S0365110X65003511 .
  6. ↑ Leszek Suski, Miroslawa Tarniowy: The phase stability of solid LiAlO 2 used for the electrolyte matrix of molten carbonate fuel cells In: Journal of Materials Science. 36, p. 5119, doi : 10.1023 / A: 1012425324262 .
  7. ↑ Takafumi Yao, Soon-Ku Hong: Oxide and Nitride Semiconductors Processing, Properties, and Applications . Springer Science & Business Media, 2009, ISBN 978-3-540-88847-5 , pp. 229 ( limited preview in Google Book search).
  8. ↑ Hadis Morkoc: Handbook of Nitride Semiconductors and Devices, Materials Properties, Physics and Growth . John Wiley & Sons, 2009, ISBN 3-527-62846-0 , pp. 382 ( limited preview in Google Book Search).