Germanium dioxide

Source: Wikipedia, the free encyclopedia.
Not to be confused with Geranic acid.
Germanium dioxide
Tetragonal rutile form
Names
IUPAC name
Germanium dioxide
Other names
Germanium(IV) oxide
Germania
ACC10380
G-15
Neutral germanium oxide (1:2)
Germanic oxide
Salt of germanium
Identifiers
3D model (
JSmol
)
ChemSpider
ECHA InfoCard
 100.013.801 Edit this at Wikidata
RTECS number
  • LY5240000
UNII
  • InChI=1S/GeO2/c2-1-3 checkY
    Key: YBMRDBCBODYGJE-UHFFFAOYSA-N checkY
  • InChI=1/GeO2/c2-1-3
    Key: YBMRDBCBODYGJE-UHFFFAOYAG
  • O=[Ge]=O
Properties
GeO2
Molar mass 104.6388 g/mol
Appearance White powder or colourless crystals
Density 4.228 g/cm3
Melting point 1,115 °C (2,039 °F; 1,388 K)
4.47 g/L (25 °C)
10.7 g/L (100 °C)
Solubility Soluble in HF,
insoluble in other acid. Soluble in strong alkaline conditions.
−34.3·10−6 cm3/mol
1.650
Structure
Hexagonal
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
0
0
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
3700 mg/kg (rat, oral)
Related compounds
Other anions
 Germanium disulfide
Germanium diselenide
Other cations
Tin dioxide
Lead dioxide
Related compounds
 Germanium monoxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Germanium dioxide, also called germanium(IV) oxide, germania, and salt of germanium,[1] is an inorganic compound with the chemical formula GeO2. It is the main commercial source of germanium. It also forms as a passivation layer on pure germanium in contact with atmospheric oxygen.

Structure

The two predominant polymorphs of GeO2 are hexagonal and tetragonal. Hexagonal GeO2 has the same structure as β-quartz, with germanium having

fused silica.[2]

Germanium dioxide can be prepared in both

GPa, the germanium coordination number increases to 6, and the dense network structure is composed of GeO6 octahedra.[4] When the pressure is subsequently reduced, the structure reverts to the tetrahedral form.[3][4] At high pressure, the rutile form converts to an orthorhombic CaCl2 form.[5]

Reactions

Heating germanium dioxide with powdered germanium at 1000 °C forms germanium monoxide (GeO).[2]

The hexagonal (d = 4.29 g/cm3) form of germanium dioxide is more soluble than the rutile (d = 6.27 g/cm3) form and dissolves to form germanic acid, H4GeO4, or Ge(OH)4.

o-diphenols.[7]

In contact with hydrochloric acid, it releases the volatile and corrosive germanium tetrachloride.

Uses

The

lenses, and for the core of fiber-optic lines. See Optical fiber for specifics on the manufacturing process. Both germanium and its glass oxide, GeO2, are transparent to the infrared (IR) spectrum. The glass can be manufactured into IR windows and lenses, used for night-vision technology in the military, luxury vehicles,[8] and thermographic cameras. GeO2 is preferred over other IR transparent glasses because it is mechanically strong and therefore preferred for rugged military usage.[9]

A mixture of silicon dioxide and germanium dioxide ("silica-germania") is used as an optical material for

optical waveguides.[10] Controlling the ratio of the elements allows precise control of refractive index. Silica-germania glasses have lower viscosity and higher refractive index than pure silica. Germania replaced titania as the silica dopant for silica fiber, eliminating the need for subsequent heat treatment, which made the fibers brittle.[11]

Germanium dioxide is also used as a

semiconductor materials
.

Germanium dioxide is used in algaculture as an inhibitor of unwanted diatom growth in algal cultures, since contamination with the comparatively fast-growing diatoms often inhibits the growth of or outcompetes the original algae strains. GeO2 is readily taken up by diatoms and leads to silicon being substituted by germanium in biochemical processes within the diatoms, causing a significant reduction of the diatoms' growth rate or even their complete elimination, with little effect on non-diatom algal species. For this application, the concentration of germanium dioxide typically used in the culture medium is between 1 and 10 mg/L, depending on the stage of the contamination and the species.[13]

Toxicity and medical

Germanium dioxide has low toxicity, but it is nephrotoxic in higher doses.[citation needed]

Germanium dioxide is used as a germanium supplement in some questionable dietary supplements and "miracle cures".[14] High doses of these resulted in several cases of germanium poisonings.

References

  1. ^ "US Patent Application for Esterification catalysts Patent Application (Application #20020087027 issued July 4, 2002) - Justia Patents Search". patents.justia.com. Retrieved 2018-12-05.
  2. ^
    ISBN 978-0-08-037941-8
    .
  3. ^
    doi:10.1103/PhysRevB.81.014202
    .
  4. ^
    PMID 15447351
    .
  5. doi:10.1007/s002690000092
    .
  6. ^
    ISBN 0-12-352651-5
    .
  7. ISSN 1383-5866
    .
  8. ^ "The Elements", C. R. Hammond, David R. Lide, ed. CRC Handbook of Chemistry and Physics, Edition 85 (CRC Press, Boca Raton, FL) (2004).
  9. ^ "Germanium" Mineral Commodity Profile, U.S. Geological Survey, 2005.
  10. ^ Robert D. Brown Jr. (2000). "Germanium" (PDF). U.S. Geological Survey.
  11. ^ Chapter Iii: Optical Fiber For Communications. Archived 2006-06-15 at the Wayback Machine.
  12. S2CID 98758568
    .
  13. ISBN 9780120884261
    .
  14. PMID 9237323
    .
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