Potassium tellurite

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Crystal structure
Unit cell of potassium tellurite
__ K +      __ O 2−      __ Te 4+
Crystal system

trigonal

Space group

P 3 (No. 147)Template: room group / 147

Lattice parameters

a = 6.2792 Å, c = 7.0694 Å

General
Surname Potassium tellurite
other names
  • Potassium monotellurite
  • Kalium telluricum
  • Potassium tellurate (IV)
Ratio formula K 2 TeO 3
Brief description

white solid

External identifiers / databases
CAS number
  • 7790-58-1
  • 123333-66-4 (trihydrate)
PubChem 65186
Wikidata Q3983056
properties
Molar mass 253.79 g mol −1
Physical state

firmly

density

2.52 g cm −3 (trihydrate)

Melting point

460–470 ° C (decomposition)

solubility

soluble in water (2300 g l −1 at 20 ° C, trihydrate)

safety instructions
GHS labeling of hazardous substances
06 - Toxic or very toxic

danger

H and P phrases H: 301
P: 301 + 330 + 331 + 310
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Potassium tellurite is an inorganic chemical compound of potassium from the group of tellurites , which is usually present as a trihydrate.

Extraction and presentation

Potassium tellurite can be obtained by reacting tellurium dioxide with potassium hydroxide or potassium carbonate . Depending on the mixing ratio, potassium ditellurite K 2 Te 2 O 5 , potassium tritellurite or potassium tetratellurite K 2 Te 4 O 9 can also be formed.

properties

Potassium tellurite is a white solid that is soluble in water with an alkaline reaction. When heated to 460–470 ° C, decomposition occurs through the absorption of oxygen and the formation of potassium tellurate . The trihydrate has a crystal structure with the space group Pnma (space group no. 62) . The anhydrate has a trigonal crystal structure with the space group P 3 (space group no. 147) . Template: room group / 62 Template: room group / 147

use

Potassium tellurite is used in solutions 1: 50000 for the detection of living pathogenic bacteria (e.g. diphtheria bacteria ) in sera and the like. These produce characteristic blackening through reduction.

Individual evidence

  1. ↑ a b L. Andersen, V. Langer, A. Strömberg, D. Strömberg: The structure of K2TeO3 - an experimental and theoretical study. In: Acta Crystallographica Section B Structural Science. 45, 1989, p. 344, doi : 10.1107 / S0108768189004684 .
  2. ↑ a b c d e data sheet Potassium tellurite, ≥95.0% (calc. On dry substance, RT) from Sigma-Aldrich , accessed on December 29, 2017 ( PDF ).
  3. ↑ a b c G. B. Johansson, O. Lindqvist: The crystal structure of dipotassium tellurate (IV) trihydrate, K2TeO3.3H2O. In: Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 34, 1978, p. 2959, doi : 10.1107 / S0567740878009826 .
  4. ↑ a b Data sheet potassium tellurite hydrate (PDF) from Merck , accessed on December 29, 2017.
  5. ^ A b Karl A. Hofmann: Textbook of Inorganic Experimental Chemistry . Springer-Verlag, 2013, ISBN 978-3-663-04369-0 , pp. 767 ( limited preview in Google Book search).
  6. ↑ Entry on potassium tellurite. In: Römpp Online . Georg Thieme Verlag, accessed on December 29, 2017.
  7. ^ PH List, Ludwig Hörhammer: Chemicals and Drugs (HM) . Springer-Verlag, 2013, ISBN 978-3-642-65643-9 , pp. 387 ( limited preview in Google Book search).
  8. ↑ K. Pichhardt: Food Microbiology Basics for Practice . Springer-Verlag, 2013, ISBN 978-3-642-96849-5 , p. 112.