Monogerman
Structural formula | ||||||||||||||||
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General | ||||||||||||||||
Surname | Monogerman | |||||||||||||||
other names |
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Molecular formula | GeH 4 | |||||||||||||||
Brief description |
colorless gas with an unpleasant odor |
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properties | ||||||||||||||||
Molar mass | 76.62 g mol −1 | |||||||||||||||
Physical state |
gaseous |
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density |
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Melting point |
−166 ° C |
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boiling point |
−88.5 ° C |
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solubility |
Hydrolysis in water |
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Refractive index |
1.451 (16.85 ° C) |
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safety instructions | ||||||||||||||||
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MAK |
Switzerland: 0.2 ml m −3 or 0.6 mg m −3 |
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As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C |
Monogerman (GeH 4 ) is the simplest chemical compound from the group of Germans (a combination of germanium and hydrogen ). It is a very reactive, toxic, easily decomposable gas with an unpleasant odor. It is used in semiconductor technology .
Occurrence
Monogerman has been detected in Jupiter's atmosphere .
Extraction and presentation
Monogerman is formed when salt-like germanides (germanium metal compounds) decompose in acids , such as magnesium germanide in dilute hydrochloric acid :
- .
Monogerman can also be represented by the direct reaction of germanium with hydrogen, whereby other germanium hydrides ( Germane) such as germanium hexahydride / digerman (Ge 2 H 6 ) and germanium octahydride / trigerman (Ge 3 H 8 ) are also formed. The synthesis of monogerman is easier and more pure by reacting germanium tetrachloride with methane and palladium as a catalyst . The yield is 98%, carbon tetrachloride is formed as a by-product :
Monogerman can also be obtained on a laboratory scale by reacting germanium (IV) compounds with hydrides. A typical synthesis of this type is sodium germanate Na 2 GeO 3 with sodium borohydride
properties
Monogerman has a critical temperature of 34.85 ° C, a critical pressure of 55.5 bar and a critical density of 0.598 kg · l −1 .
use
Monogerman is used in the electronics industry for epitaxy and doping .
safety instructions
Monogerman forms highly explosive mixtures with air from a proportion of approx. 10.1%. Since the gas is very heavy and normally only accumulates up to 5% in the air, it can only be classified as extremely flammable.
Monogerman is very poisonous. In the event of acute poisoning with large amounts of Monogerman, the following symptoms occur:
- Widening of the blood vessels ( arteriectasia )
- Ptosis
- cyanosis
- tremor
The reason for this is the interruption of the oxygen transport, since Monogerman reacts with the oxygen transported in the blood to form germanium (IV) oxide and water:
This can be prevented by giving complexing agents such as EDTA .
Individual evidence
- ↑ a b c d e f g h i Entry on Monogerman in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
- ↑ PG Sennikov, VE Shkrunin, DA Raldugin, KG Tokhadze: Weak Hydrogen Bonding in Ethanol and Water Solutions of Liquid Volatile Inorganic Hydrides of Group IV-VI Elements (SiH 4 , GeH 4 , PH 3 , AsH 3 , H 2 S, and H 2 Se). 1. IR Spectroscopy of H Bonding in Ethanol Solutions in Hydrides . In: The Journal of Physical Chemistry . tape 100 , no. January 16 , 1996, ISSN 0022-3654 , pp. 6415-6420 , doi : 10.1021 / jp953245k .
- ↑ Swiss Accident Insurance Fund (Suva): Limits - Current MAK and BAT values (search for 7782-65-2 or Monogerman ), accessed on November 2, 2015.
- ↑ NASA report on Jupiter (English)
- ↑ LM Dennis: Germanium. Summary of studies in the Department of Chemistry, Cornell University, 1921-1927 . In: Journal of Inorganic and General Chemistry . tape 174 , no. 1 , August 2, 1928, p. 97 , doi : 10.1002 / zaac.19281740114 .