Germanium dioxide, also called germanium oxide and germania, is an inorganic compound, an oxide of germanium. Its chemical formula is GeO₂. Its CAS number is [1310-53-8] [1]. Its other names are germanic acid, G-15, and ACC10380. It has the appearance of white powder or colorless crystals, with melting point of 1115 °C. Germanium dioxide is a structural analog of silicon dioxide. It can be prepared both crystalline and amorphous. It forms a passivation layer on pure germanium in contact with atmospheric oxygen. An inorganic compound is a chemical compound that is not an organic compound. ... An oxide is a chemical compound of oxygen with other chemical elements. ... General Name, Symbol, Number germanium, Ge, 32 Chemical series metalloids Group, Period, Block 14, 4, p Appearance grayish white Atomic mass 72. ... General Name, Symbol, Number germanium, Ge, 32 Chemical series metalloids Group, Period, Block 14, 4, p Appearance grayish white Atomic mass 72. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences and alloys. ... R-phrases R42 R43 R49 S-phrases S22 S36 S37 S45 S53 Flash point non-flammable Supplementary data page Structure and properties n, εr, etc. ... Crystal (disambiguation) Insulin crystals A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ... An amorphous solid is a solid in which there is no long-range order of the positions of the atoms. ... Passivation is the process of making a material passive in relation to another material prior to using the materials together. ...

Germanium dioxide's refractive index and optical dispersion properties make it useful as an optical material for wide-angle lenses and in optical microscope objective lenses. It is transparent in infrared. The refractive index (or index of refraction) of a material is the factor by which the phase velocity of electromagnetic radiation is slowed in that material, relative to its velocity in a vacuum. ... In photography and cinematography, a wide-angle lens is a lens whose focal length is shorter than the focal length of a normal lens. ... The optical microscope is a type of microscope which uses visible light and a system of lenses to magnify images of small samples. ... An objective in optics is the lens or mirror in a microscope, telescope, camera or other optical instrument, that receives the first light rays from the object being observed. ... A lens. ... Image of two girls in mid-infrared (thermal) light (false color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ...

Mixture of silicon dioxide and germanium dioxide ("silica-germania") is used as an optical material for optical fibers and optical waveguides. 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.^[1] A bundle of optical fibers. ... An optical waveguide is a form of a dielectric waveguide, that is capable of guiding an optical signal. ... Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturally occurring oxide of titanium, chemical formula TiO2. ...

Germanium dioxide is also used as a catalyst in production of polyethylene terephthalate resin, and for production of other germanium compounds. It is used as a feedstock for production of some phosphors and semiconductor materials. It has been suggested that this article or section be merged into Catalysis. ... Polyethylene terephthalate (aka PET, PETE, PETP,PET-P) is a thermoplastic polymer resin of the polyester family that is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination with glass fiber. ... A phosphor is a substance that can exhibit the phenomenon of fluorescence (glowing during absorption of radiation of another kind) or phosphorescence (sustained glowing without further stimulus). ... Semiconductor materials are insulators at absolute zero temperature that conduct electricity in a limited way at room temperature (see also Semiconductor). ...

Germanium dioxide has low toxicity; in higher doses it is nephrotoxic. It is not flammable. In contact with hydrochloric acid it releases volatile and corrosive germanium tetrachloride. It is moderately soluble in water, with which it reacts and forms germanic acid. Nephrotoxicity is a poisonous effect of some substances, both toxins and medication, on the kidney. ... The chemical compound hydrochloric acid is the aqueous (water-based) solution of hydrogen chloride (HCl). ... Flash point None R/S statement R: ? S: ? RTECS number LY5220000 Related compounds Other anions  ? Other cations  ? Related ?  ? Related compounds  ? Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references Germanium tetrachloride is a colourless liquid primary used...

Germanium dioxide is used as a germanium supplement in some questionable dietary supplements and "miracle cures". High doses of these resulted in several cases of germanium poisonings. A prescribed dietary supplement is intended to supply nutrients (vitamins, minerals, fatty acids or amino acids) that are missing or not consumed in sufficient quantity in a persons diet. ...

At very high pressures, germanium dioxide forms unusual octahedral structure.^[2][3]

In manufacture of integrated circuits and transistors, germanium dioxide is a rather poor dielectric and is chemically unstable, which is one of the disadvantages of germanium in comparison with silicon.

References

1. ^ http://www.sri.com/policy/csted/reports/sandt/techin2/chp3.html
2. ^ http://www.anl.gov/Media_Center/News/2004/IPNS041210.html
3. ^ http://www.anl.gov/Media_Center/Argonne_News/2005/an050117.htm

External links

• Links to external chemical sources.