| Identification | More | [Name]
Germanium | [CAS]
7440-56-4 | [Synonyms]
Ge
HCl tr%
GE007930
GE004600
GE007920
GE003121
GE003120
GE003130
GE003122
GE003020
GE003030
GE003101
GE003055
GE003100
GE007910
GE003053
GE003052
GE003131
GE004700
GE003010
98.5% ACS
GERMANIUM
Azure B
Sudan II &ge
U in HNO3 2%
germanium(4+)
Ponceau S &ge
Tartrazine &ge
Evans Blue &ge
Germaniumwafer
germanium atom
Tb in HNO3 10%
Bi in HNO3 10%
GERMANIUM METAL
Germanium 4N-6N
Allura Red
Germanium ingots
Germanium sludge
Cermanium powder
Germanium pieces
Germanium powder
germaniumelement
GERMANIUM: 99.9%
Xylenol Blue &ge
GERMANIUM, 99.99%
80% (Dye content)
90% (Dye content)
85% (Dye content)
Erioglaucine
Metanil Yellow &ge
Thioflavin T
Patent Blue V
GermaniumpiecesNmm
Ge Target 99.999%
GERMANIUM STANDARD
Germanium, 99.999%
10ug/l each of Be
GERMANIUM, 99.9999%
Germaniumpowdermesh
Germaniummeshpowder
Quinaldine Red
Brilliant Yellow &ge
GerManiuM Nanopowder
GermaniumpowderNmesh
Germanium Nanoprisms
Chlorophenol Red
germanium monohydride
germanium,metalpowder
Crystal Scarlet
Calcium hydroxide &ge
Bismark Brown R
Orange II Certifed &ge
Acridine Yellow G
Indocyanine Green
GERMANIUM ICP STANDARD
GerManiuM piece,1-5MM.
GermaniumIngots,99.999%
Germanium, Pieces 3-9mm
Brilliant Black BN
Orange G, Certified
Brilliant blue G-250 &ge
Acriflavine Neutral
Quinoline Yellow W/S &ge
Germanium,99.999%,powder
Germaniumpieces(99.999%)
Sudan III, Certified &ge
Germanium Optical Window
Germanium Stock Solution
Potassium thiocyanate &ge
Germaniumpowder(99.9999%)
Germanium, Powder 10 Mesh
getmanium monocrystalline
New Methylene Blue N
98.5% (acidimetric) (Assa
Sodium decyl sulfate
Fast Sulphon Black F
4-Bromo-7-azaindole
6-Fluoro (1H)indazole, >
Germanium Pieces 50 Ohm cm
GERMANIUM ICP/DCP STANDARD
Germanium, powder, 99.999%
GerManiuM sputtering target
GERMANIUM STANDARD SOLUTION
GERMANIUM WAFER - 25mm dia.
Germanium germanium element
Neotetrazolium Chloride
Ethyl Orange sodium salt &ge
Germanium ISO 9001：2015 REACH
6-Quinolinecarbaldehyde
GERMANIUM POWDER: 99.999%, 5N
GERMANIUM PIECES, 5N: 99.999%
Bromophenol Red Free acid
1-Boc-1H-indazol-4-amine
5-Fluoro-2-methoxyaniline, >
4-(4-Pyridinyl)piperidine, >
1-Boc-4-bromo-1H-indazole
Germanium, Pieces 3-9mm 99.999%
GERMANIUM, AAS STANDARD SOLUTION
Azetidine-3-carboxylic acid, >
Thymol Blue sodium salt ACS
Boc-2-methyl-D-phenylalanine, >
POTASSIUM CHLORIDE MOL.BIOL GRADE
GERMANIUM SINGLE ELEMENT STANDARD
Germanium, Powder 10 Mesh 99.999%
germanium coating quality balzers
Germanium, 99.9% -100 mesh powder
GERMANIUM PLASMA EMISSION STANDARD
Ethyl 6-quinolinecarboxylate
GERMANIUM, PLASMA STANDARD SOLUTION
GERMANIUM ATOMIC ABSORPTION STANDARD
GERMANIUM AA SINGLE ELEMENT STANDARD
Germanium, pieces, irregular,99.999%
Thionin Acetate Salt, Certified
Germanium rod, 6.35mm (0.25 in.) dia.
5-Chloro-2-cyano-3-fluoropyridine, >
3-Bromo-1H-pyrrolo[2,3-b]pyridine, >
GERMANIUM, POWDER, -100 MESH, 99.999+%
GerManiuM, powder, (trace Metal basis)
GERMANIUM: 99.999%, POWDER, -50 MICRON
Germanium, chip, 99.9998% metals basis
GERMANIUM ICP STANDARD TRACEABLE TO SRM
2-Chloro-4-pyrimidinecarbonitrile
GERMANIUM SINGLE ELEMENT PLASMA STANDARD
1,2,4-Trihydroxy-9,10-anthracenedione &ge
Sodium Salt (Acid Blue 3 Sodium Salt), &ge
Germanium chips, 99.999% trace metals basis
Germanium pieces, 3 to 9mm (0.1 to 0.4 in.)
Germanium AA Standard,1000 ppm in H2O tr. HF
GERMANIUM ATOMIC ABSORPTION STANDARD SOLUTION
4-Nitrophenyl-N-acetyl-b-D-galctosaminide, >
Germanium, AAS standard solution, Ge 1000μg/mL
Methyl 4-bromo-1H-pyrazole-3-carboxylate
Germanium, plasma standard solution, Ge 10μg/mL
Germanium, powder, (trace metal basis), 99.999%
GERMANIUM PLASMA EMISSION SPECTROSCOPY STANDARD
GerManiuM, 99.999%, (trace Metal basis), powder
GERMANIUM, PIECES, IRREGULAR, +10 MESH, 99.999%
mmGermanium atomic absorption standard solution
Germanium plasma standard solution, Ge 1000μg/mL
Germanium plasma standard solution, Ge 10000μg/mL
4-(2-Methoxyphenoxy)benzenesulfonyl chloride, >
Elan 5000 Detection Limit Solution - 6 components
Germanium, powder, #100 mesh, 99.99+% metals basis
Germanium atomic spectroscopy standard 1.00 Ge
Germanium pieces, ≤2cm, 99.9999% trace metals basis
Germanium pieces, 3-9mm, 99.999% trace metals basis
ICP-MS Alternate Internal Standard 2 - 8 components
Germanium pieces, Electrical Resistivity: >40 ohm-cm
Germanium pieces, ≤3.2mm, 99.999% trace metals basis
Internal standard mix for ICP-MS systems - 8 components
(2-Amino-Ethyl)ethyl-carbamic acid tert-butyl ester, >
Germanium powder, -100 mesh, >=99.99% trace metals basis
Ammonium chloride - germanium(IV) chloride solution
metel basisGermanium atomic absorption standard solution
Germanium powder, -100 mesh, >=99.999% trace metals basis
Morpholin-3-yl-acetic acid ethyl ester hydrochloride, >
Germanium ingot, zone refined, 99.9999% trace metals basis
Germanium, plasma standard solution, Specpure, Ge 10g/ml
(2-Hydroxyethyl)propyl-carbamic acid tert-butyl ester, >
Germanium, AAS standard solution, Specpure(R), Ge 1000μg/ml
Germanium ICP Std@1000 μg/mL in Water, tr Hydrofluoric acid
Germanium pieces, 2cm (0.8in) & down, 99.9999% (metals basis)
Germanium, plasma standard solution, Specpure(R), Ge 1000μg/ml
Germanium, plasma standard solution, Specpure(R), Ge 10,000μg/ml
Germanium ICP Standard@1000 μg/mL in Water, tr Hydrofluoric acid
Germanium ICP Standard@10000 μg/mL in Water, tr Hydrofluoric acid
Germanium Optical Window, 25.4mm (1.0in) dia x 2mm (0.08in) thick
Germanium Optical Window, 50.8mm (2.0in) dia x 1mm (0.04in) thick
Germanium Optical Window, 50.8mm (2.0in) dia x 2mm (0.08in) thick
Germanium Optical Window, 25.4mm (1.0in) dia x 1mm (0.04in) thick
GerManiuM pieces, 3.2MM (0.125in) and down, 99.999% (Metals basis)
Germanium ICP-MS Standard@100 μg/mL in Water, tr Hydrofluoric acid
Germanium ICP-MS Standard@1000 μg/mL in Water, tr Hydrofluoric acid
Germanium ICP-MS Standard@10000 μg/mL in Water, tr Hydrofluoric acid
Germanium rod, polycrystalline, 6.35mm dia., 99.9999% trace metals basis
Germanium pieces, 2cm (0.8in) & down, Puratronic, 99.9999+% (metals basis)
Germanium pieces, 2cm (0.8in) & down, Puratronic(R), 99.9999+% (metals basis)
Germanium single crystal disc, 10mm (0.39in) dia, 1-3mm (0.04-0.1in) thick, (110) orientation, ±0.5°
Germanium Optical Window, 25.4mm (1.0 in.) dia. x 2mm (0.08 in.) thick, Uncoated, Clear Aperture 85%, Surface Finsh 40/20 | [EINECS(EC#)]
231-164-3 | [Molecular Formula]
Ge | [MDL Number]
MFCD00085310 | [Molecular Weight]
72.64 | [MOL File]
7440-56-4.mol |
| Chemical Properties | Back Directory | [Definition]
Nonmetallic element of atomic number 32, aw72.59,
valences of 2, 4; group IVa of the periodic table. | [Appearance]
Germanium is a grayish-white, lustrous, and
brittle metalloid. The powder is grayish-black and odorless. It
is never found free and occurs most commonly in ergyrodite
and germanite. It is generally recovered as a by-product in
zinc production, coal processing, or other sources. | [Melting point ]
937 °C(lit.)
| [Boiling point ]
2830 °C(lit.)
| [density ]
5.35 g/mL at 25 °C(lit.)
| [vapor pressure ]
0Pa at 25℃ | [storage temp. ]
Flammables area | [solubility ]
insoluble in H2O, dilute acid solutions, alkaline solutions | [form ]
powder
| [color ]
Silver | [Specific Gravity]
5.35 | [Stability:]
Stable. Slightly soluble in strong acids. Incompatible with strong oxidizing agents. | [Resistivity]
53000 μΩ-cm, 20°C | [Water Solubility ]
insoluble H2O, HCl, dilute alkali hydroxides; attacked by aqua regia [MER06] | [Crystal Structure]
Cubic, Diamond Structure - Space Group Fd3m | [Merck ]
13,4419 | [Exposure limits]
ACGIH: TWA 0.5 ppm(2.5 mg/m3); Ceiling 2 ppm (Skin)
OSHA: TWA 3 ppm
NIOSH: IDLH 30 ppm(250 mg/m3); TWA 3 ppm(2.5 mg/m3); Ceiling 6 ppm(5 mg/m3) | [History]
Germanium was predicted by Mendeleev in 1871 as ekasilicon, and discovered by Winkler in 1886. The metal is found in argyrodite, a sulfide of germanium and silver; in germanite, which contains 8% of the element; in zinc ores; in coal; and in other minerals. Germanium is frequently obtained commercially from flue dusts of smelters processing zinc ores, and has been recovered from the by-products of combustion of certain coals. Its presence in coal insures a large reserve of the element in the years to come. Germanium can be separated from other metals by fractional distillation of its volatile tetrachloride. The tetrachloride may then be hydrolyzed to give GeO2; the dioxide can be reduced with hydrogen to give the metal. Recently developed zone-refining techniques permit the production of germanium of ultra-high purity. The element is a gray-white metalloid, and in its pure state is crystalline and brittle, retaining its luster in air at room temperature. Germanium is a very important semiconductor material. Zone-refining techniques have led to production of crystalline germanium for semiconductor use with an impurity of only one part in 1010. Doped with arsenic, gallium, or other elements, it is used as a transistor element in thousands of electronic applications. Its application in fiber optics and infrared optical systems now provides the largest use for germanium. Germanium is also finding many other applications including use as an alloying agent, as a phosphor in fluorescent lamps, and as a catalyst. Germanium and germanium oxide are transparent to the infrared and are used in infrared spectrometers and other optical equipment, including extremely sensitive infrared detectors. Germanium oxide’s high index of refraction and dispersion make it useful as a component of glasses used in wide-angle camera lenses and microscope objectives. The field of organogermanium chemistry is becoming increasingly important. Certain germanium compounds have a low mammalian toxicity, but a marked activity against certain bacteria, which makes them of interest as chemotherapeutic agents. The cost of germanium is about $10/g (99.999% purity). Thirty isotopes and isomers are known, five of which occur naturally. | [LogP]
4.14 at 20℃ | [CAS DataBase Reference]
7440-56-4(CAS DataBase Reference) | [NIST Chemistry Reference]
Germanium(7440-56-4) | [EPA Substance Registry System]
7440-56-4(EPA Substance) |
| Hazard Information | Back Directory | [Chemical Properties]
Germanium is a grayish-white, lustrous, and
brittle metalloid. The powder is grayish-black and odorless. It
is never found free and occurs most commonly in ergyrodite
and germanite. It is generally recovered as a by-product in
zinc production, coal processing, or other sources. | [Chemical Properties]
greyish-white lustrous brittle solid, odourless | [Potential Exposure]
Because of its semiconductor proper ties, germanium is widely used in the electronic industry in
rectifiers, diodes, and transistors. It is alloyed with alumi num, aluminum magnesium, antimony, bronze, and tin to
increase strength, hardness, or corrosion resistance. In the
process of alloying germanium and arsenic, arsine may be
released; stibine is released from the alloying of germanium and antimony. Germanium is also used in the manufacture
of optical glass for infrared applications; red-fluorescing
phosphors; and cathodes for electronic valves; and in elec troplating; in the hydrogenation of coal; and as a catalyst,
particularly at low temperatures. Certain compounds are
used medically. Industrial exposures to the dust and fumes
of the metal or oxide generally occur during separation and
purification of germanium, welding, multiple-zone melting
operations, or cutting and grinding of crystals. Germanium
tetrahydride (germanium hydride, germane, and monoger mane) and other hydrides are produced by the action of a
reducing acid on a germanium alloy. | [First aid]
Move victim to fresh air. Call 911 or emergency
medical service. Give artificial respiration if victim is not
breathing. Do not use mouth-to-mouth method if victim
ingested or inhaled the substance; give artificial respira tion with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device.
Administer oxygen if breathing is difficult. Remove and
isolate contaminated clothing and shoes. In case of contact
with substance, immediately flush skin or eyes with run ning water for at least 20 minutes. For minor skin contact,
avoid spreading material on unaffected skin. Keep victim
warm and quiet. Effects of exposure (inhalation, ingestion,
or skin contact) to substance may be delayed. Ensure that
medical personnel are aware of the material(s) involved
and take precautions to protect themselves. Medical obser vation is recommended for 24 to 48 hours after breathing
overexposure, as pulmonary edema may be delayed. As
first aid for pulmonary edema, a doctor or authorized para medic may consider administering a drug or other inhala tion therapy. | [Shipping]
UN3089 Metal powders, flammable, n.o.s.,
Hazard Class: 4.1; Labels: 4.1-Flammable solid. UN1759
Corrosive solids, n.o.s., Hazard class: 8; Labels:
8-Corrosive material, Technical Name required. | [Incompatibilities]
A strong reducing agent and flammable
solid. Finely divided metal is incompatible with oxidizing
and nonoxidizing acids, ammonia, bromine, oxidizers, aqua
regia, sulfuric acid, carbonates, halogens, and nitrates.
Explosive reaction or ignition with potassium chlorate,
potassium nitrate, chlorine, bromine, oxygen, and potas sium hydroxide in the presence of heat. Violent reaction
with strong acids: aqua regia, nitric, and sulfuric.
Incompatible with oxidizers (chlorates, nitrates, peroxides,
permanganates, perchlorates, chlorine, bromine, fluorine,
etc.); contact may cause fires or explosions. | [Description]
Germanium is extracted from zinc ores in a very complicated process as it has aqueous properties similar
to those of zinc. Once the germanium/zinc mixture has been sufficiently enriched with germanium, it is
heated in HCl with Cl2 in order to allow the formation of germanium tetrachloride (GeCl2). | [Waste Disposal]
Recovery and return to sup pliers for reprocessing is preferable. | [Physical properties]
Germanium has a gray shine with a metallic silvery-white luster. It is a brittle elementclassed as a semimetal or metalloid, meaning it is neither a metal such as iron or copper nora nonmetal, such as phosphorus, sulfur, or oxygen. Germanium has some properties likea metal and some like a nonmetal. It is a crystal in its pure state, somewhat like silicon. Itwill combine with oxygen to form germanium dioxide, which is similar to silicon dioxide(sand).
Germanium is not found in its free elemental state because it is much too reactive. For themost part, it is found combined with oxygen, either as germanium monoxide or as germaniumdioxide. Also, it is recovered from the ores of zinc, copper, and arsenic and the flue depositsof burning coal.
The crystal structure of germanium is similar to that of diamonds and silicon, and its semiconductingproperties are also similar to silicon.The melting point of germanium is 938.3°C, its boiling point is 2833°C, and its densityis 5.323 g/cm3. | [Isotopes]
There are a total of 38 isotopes of Germanium, five of which are stable. Thestable isotopes of germanium and their natural abundance are as follows: Ge-70 =20.37%, Ge-72 = 27.31%, Ge-73 = 7.76%, Ge-74 = 36.73%, and Ge-76 = 7.83%.Ge-76 is considered stable because it has such a long half-life (0.8×10+25 years)All theother 33 isotopes are radioactive and are produced artificially. | [Origin of Name]
Germanium’s name was derived from the Latin word Germania, meaning
“Germany.” | [Occurrence]
Germanium, the 52nd most abundant element in the Earth’s crust, is widely distributed,but never found in its natural elemental state. It is always combined with other elements,particularly oxygen.
Germanium’s main minerals are germanite, argyrodite, renierite and canfieldite, all ofwhich are rare. Small amounts of germanium are found in zinc ore, as well as in copper andarsenic ores. It is known to concentrate in certain plants on Earth, particularly in coal: commercialquantities are collected from the soot in the stacks where coal is burned. | [Characteristics]
Once germanium is recovered and formed into blocks, it is further refined by the manufacturerof semiconductors. It is melted, and the small amounts of impurities such as arsenic, gallium,or antimony, are added. They act as either electron donors or acceptors that are infused(doped) into the mix. Then small amounts of the molten material are removed and used togrow crystals of germanium that are formed into semiconducting transistors on a germaniumchip. The device can now carry variable amounts of electricity because it can act as both aninsulator and a conductor of electrons, which is the basis of modern computers. | [Purification Methods]
Copper contamination on the surface and in the bulk of single crystals of Ge can be removed by immersion in molten alkali cyanide under N2. The Ge is placed in dry K and/or Na cyanide powder in a graphite holder in a quartz or porcelain boat. The boat is then inserted into a heated furnace which, after a suitable time, is left to cool to room temperature. At 750o, a 1mm thickness of metal requires about 1minute, whereas 0.5cm needs about half hour. The boat is removed from the furnace, and the solid samples are taken out with plastic-coated tweezers, carefully rinsed in hot water and dried in air [Wang J Phys Chem 60 45 1956, Schenk in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 712 1963]. Care with the use of cyanide. | [Hazard]
Many of the chemicals used in the semiconductor industries are highly toxic. For example,germanium-halogen compounds are extremely toxic, both as a powder and in a gaseous state.Precautions should be taken when working with germanium as with similar metalloids fromgroup 14 (IVA). | [Flammability and Explosibility]
Notclassified | [Industrial uses]
A rare elemental metal, germanium (Ge) has agrayish white crystalline appearance and hasgreat hardness: 6.25 Mohs. Its specific gravityis 5.35, and melting point is 937°C. It is resistantto acids and alkalies. It has metallic-appearingcrystals with diamond structure, givesgreater hardness and strength to aluminum andmagnesium alloys, and as little as 0.35% in tinwill double the hardness. It is not used commonlyin alloys, however, because of its rarityand great cost. It is used chiefly as metal inrectifiers and transistors. An Au–Ge alloy, withabout 12% germanium, has a melting point of359°C and has been used for soldering jewelry.
Germanium is obtained as a by-productfrom flue dust of the zinc industry, or it can beobtained by reduction of its oxide from the ores,and is marketed in small irregular lumps. Germaniumcrystals are grown in rods up to 3.49cm in diameter for use in making transistorwafers. High-purity crystals are used for both P and Nsemiconductors. They are easier topurify and have a lower melting point than othersemiconductors, specifically silicon. | [Industrial uses]
Germanium lenses and filters have been usedin instruments that operate in the infraredregion of the spectrum. Windows and lenses ofgermanium are vital components of some laserand infrared guidance or detection systems.Glasses prepared with germanium dioxide havea higher refractivity and dispersion than docomparable silicate glasses and may be used inwide-angle camera lenses and microscopes. | [Environmental Fate]
Metals are recalcitrant to degradation; therefore, no biodegradation studies have been performed on germanium compounds. Naturally occurring germanium exists in mineral ores; therefore, the levels of free germanium are expected to be low and of low concern for bioaccumulation in aquatic and terrestrial species, due to negligible exposures. |
| Safety Data | Back Directory | [Hazard Codes ]
F,Xi | [Risk Statements ]
R36/37/38:Irritating to eyes, respiratory system and skin .
R36/38:Irritating to eyes and skin .
R11:Highly Flammable. | [Safety Statements ]
S26:In case of contact with eyes, rinse immediately with plenty of water and seek medical advice .
S36/39:Wear suitable protective clothing and eye/face protection .
S2:Keep out of the reach of children . | [RIDADR ]
UN 3089 4.1/PG 2
| [WGK Germany ]
3
| [RTECS ]
LY5200000
| [TSCA ]
Yes | [HazardClass ]
8 | [PackingGroup ]
III | [HS Code ]
28053090 | [Hazardous Substances Data]
7440-56-4(Hazardous Substances Data) |
| Questions And Answer | Back Directory | [Chemical Properties]
Germanium is a grayish-white, lustrous, brittle metalloid. When crystalline, it exists in a diamond-cubic structure. It has a very low vapor pressure and is insoluble in water.
Germanium is never found in a pure state in the environment. In the refined state, it is a gray– white metalloid. Like its counterparts in group 14 of the periodic table (carbon, silicon, tin, and lead), germanium has both metallic and nonmetallic properties. It has a valence of +2 or +4; the atom usually is quadrivalent.
Germanium is a true semiconductor, is highly transparent to infrared light, and has a high index of refraction. Germanium and its compounds or alloys have found wide use in the optical and electronics industries. In electronic applications, it often is alloyed with antimony, gallium, indium, or arsenic.
Germanium is a low production volume chemical.
| [History]
The existence of this element was predicted by Mendeleev in 1871 in his periodic scheme. He predicted that it should belong to the carbon group and occupy the position just below silicon. He therefore named it ekasilicon.
Fifteen years later in 1886, the predicted element was discovered by Clemens Winkler who isolated it from the mineral argyrodite. It was named in honor of Germany.
Germanium occurs in nature mostly as sulfide ores. It is found in the minerals germanite, 7CuS•FeS•GeS2; argyrodite, 4Ag2S•GeS2; renierite (Cu,Ge,Fe,Zn,As)S; and canfieldite, 4Ag2S. It also is found in small quantities in many zinc blende ores from which it is commercially extracted in the United States. Trace quantities of germanium are also found in many coals. Its abundance in the earth’s crust is about 1.5 mg/kg and concentration in sea water is 0.05 µg/L.
| [Uses]
The most important uses of germanium are in electronic industries. It is a semiconductor material exhibiting an exponential increase of conductivity with increasing temperature. The element can be prepared in extreme purification with a high degree of crystalline perfection so as to yield highly characterized surfaces. Other applications of germanium are in infrared detectors, microscopes and various optical instruments; as a phosphor in fluorescent lamps; as an alloying agent; and as a catalyst.
| [Production Methods]
In the United States, germanium is obtained as a by-product of zinc production from zinc blende ores. The ore is concentrated by the flotation process. Concentrated ore is then roasted, converting zinc and the impurity metals to their oxides. Heating the crude oxides with sodium chloride and coal converts germanium and other impurity metal oxides into their volatile chlorides. The chloride vapors are condensed and germanium chloride, GeCl4, is separated from the condensate by fractional distillation.
Germanium also is recovered from coal that contains this metal at trace concentrations. Coal ash and fine dusts are mixed with sodium carbonate, copper oxide, calcium oxide, and coal dust, and smelted. The crude oxide products are converted to their volatile chlorides. Germanium chloride is isolated from the condensate products by fractional distillation.
High purity (99.9999%) germanium may be produced by fractional distillation of the chloride in the presence of hydrochloric acid and chlorine in quartz stills, followed by hydrolysis of the purified chloride with double distilled water to produce germanium oxide, GeO2. The oxide is reduced with hydrogen at 1,000°C. Exceedingly high purity germanium for semiconductor applications may be obtained from the high purity grade material by the zone refining process. Impurities present in germanium are more soluble in its melt than the solid metal. Thus, repeated passes of a molten zone along the impure ingot of germanium effectively removes trace impurities from the solid metal ingot.
Doping of the metal for its solid state electronic use may be carried out either by adding trace amounts of doping agents into the melts before a single crystal is grown from the melt or into the prepared single crystal by solid state diffusion. Single crystals up to a few inches in diameter may be prepared from the melt by the Czochralski technique, which involves contacting the melt with a seed crystal under an inert atmosphere and controlled conditions of temperature and seeding.
| [Reactions]
The chemical properties of germanium fall between those of silicon and tin. It forms both the divalent and tetravalent compounds, the oxidation state +4 being more stable than the +2 oxidation state. The metal is stable in air and water at ambient temperatures. However, it reacts with oxygen at elevated temperatures forming divalent and tetravalent oxides, GeO and GeO2.
While no reaction occurs with dilute mineral acids, the compound is attacked by concentrated HNO3 and H2SO4. Also, no reaction occurs with caustic alkalies.
When heated with carbon dioxide at 800°C, the divalent oxide is formed:
Ge + CO2 →GeO + CO
The metal also reduces the tetravalent oxide to the divalent oxide upon heating at elevated temperatures:
Ge + GeO2→ 2GeO
Heating with chlorine at elevated temperatures yields germanium tetrachloride:
Ge + 2Cl2 →GeCl4
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