Digermane

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Digermane
Names
IUPAC name
Digermane
Identifiers
3D model (
JSmol
)
ChemSpider
ECHA InfoCard
 100.159.079 Edit this at Wikidata
  • InChI=1S/Ge2H6/c1-2/h1-2H3
    Key: MOFQWXUCFOZALF-UHFFFAOYSA-N
  • InChI=1/Ge2H6/c1-2/h1-2H3
    Key: MOFQWXUCFOZALF-UHFFFAOYAF
  • [GeH3][GeH3]
Properties
Ge2H6
Molar mass 151.328 g/mol
Appearance Colorless gas
Density 1.98 kg/m3[1]
Melting point −109 °C (−164 °F; 164 K)
Boiling point 29 °C (84 °F; 302 K)
Insoluble
Hazards
GHS labelling:
GHS02: FlammableGHS06: ToxicGHS07: Exclamation mark
Danger
H220, H302, H312, H315, H319, H330, H335
P210, P260, P261, P264, P270, P271, P280, P284, P301+P312, P302+P352, P304+P340, P305+P351+P338, P310, P312, P320, P321, P322, P330, P332+P313, P337+P313, P362, P363, P377, P381, P403, P403+P233, P405, P501
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Digermane is an inorganic compound with the chemical formula Ge2H6. One of the few hydrides of germanium, it is a colourless liquid. Its molecular geometry is similar to ethane.[2]

Synthesis

Digermane was first synthesized and examined in 1924 by Dennis, Corey, and Moore. Their method involves the hydrolysis of magnesium germanide using hydrochloric acid.[3] Many of the properties of digermane and trigermane GeH3GeH2GeH3 were determined in the following decade using electron diffraction studies.[4] Further considerations of the compound involved examinations of various reactions such as pyrolysis and oxidation.

Digermane is produced together with germane by the reduction of germanium dioxide with sodium borohydride. Although the major product is germane, a quantifiable amount of digermane is produced in addition to traces of trigermane.[5] It also arises by the hydrolysis of magnesium-germanium alloys.[6]

Reactions

The reactions of digermane exhibit some differences between analogous compounds of the Group 14 elements carbon and silicon. However, there are still some similarities seen, especially in regards to pyrolysis reactions.

The

oxidation of digermane takes place at lower temperatures than monogermane. The product of the reaction, germanium oxide, has been shown to act in turn as a catalyst of the reaction. This exemplifies a fundamental difference between germanium and the other Group 14 elements carbon and silicon (carbon dioxide and silicon dioxide do not exhibit the same catalytic properties).[7]

2 Ge2H6 + 7 O2 → 4 GeO2 + 6 H2O

In liquid ammonia, digermane undergoes disproportionation. Ammonia acts as a weakly basic catalyst. Products of the reaction are hydrogen, germane, and a solid polymeric germanium hydride.[8]

Pyrolysis of digermane is proposed to follow multiple steps:

Ge2H6 → 2 GeH3
GeH3 + Ge2H6 → GeH4 + Ge2H5
Ge2H5 → GeH2 + GeH3
GeH2 → Ge + H2
2 GeH2 → GeH4 + Ge
n GeH2 → (GeH2)n

This pyrolysis has been found to be more endothermic than the pyrolysis of disilane. This difference is attributed to the greater strength of the Ge-H bond vs the Si-H bond. As seen in the last reaction of the mechanism above, pyrolysis of digermane may induce polymerization of the GeH2 group, where GeH3 acts as a chain propagator and molecular hydrogen gas is released.

nanowires.[10]

Digermane is a precursor to GeH3−GH2−E−CF3, where E is either sulfur or selenium. These trifluoromethylthio (−S−CF3) and trifluoromethylseleno (−Se−CF3) derivatives possess a markedly higher thermal stability than digermane itself.[11]

Applications

Digermane has a limited number of applications; germane itself is the preferred volatile germanium hydride. Generally, digermane is primarily used a precursor to germanium for use in various applications. Digermane can be used to deposit Ge-containing semiconductors via chemical vapor deposition.[12]

References

  1. ISBN 9781498754293
    .
  2. doi:10.1021/ja01274a024
    .
  3. doi:10.1021/ja01668a015
    .
  4. doi:10.1021/ja01274a024
    .
  5. S2CID 227343469
    .
  6. ISBN 978-0-08-037941-8
    .
  7. doi:10.1039/jr9380001900
    .
  8. doi:10.1021/ic50070a037
    .
  9. PMID 24540662
    .
  10. PMID 20608714
    .
  11. doi:10.1021/ic50193a002
    .
  12. doi:10.1021/cm100915q
    .
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