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Germanium

physical science Maturity 11-13 Next article →

Germanium is a lustrous, grayish-white chemical element with the symbol Ge and atomic number 32. It is classified as a metalloid, meaning it possesses properties of both metals and nonmetals.

Winkler preparate 1886 1904
Winkler preparate 1886 1904

Because it is chemically similar to silicon, it often forms complexes with oxygen in nature. It is a hard but brittle substance that belongs to the carbon group on the periodic table. While it is highly useful in modern technology, it is relatively rare. It ranks 50th in abundance among all elements in the Earth's crust.

Renierit
Renierit

As a semiconductor, germanium plays a vital role in controlling electrical currents. A semiconductor is a material that can conduct electricity better than an insulator but not as well as a metal. In the first decade of semiconductor electronics, devices relied almost entirely on germanium. The development of the germanium transistor in 1948 opened doors to countless electronic applications. However, high-purity silicon eventually began replacing germanium in many transistors and diodes. This happened because silicon has superior electrical properties and is much easier to source from sand.

Germane-2D-dimensions
Germane-2D-dimensions

Today, germanium is used for several specialized high-tech purposes. It is essential for fiber-optic communication systems, which carry information using light.

Singlemode fibre structure
Singlemode fibre structure

It is also used in infrared optics, solar cell applications, and light-emitting diodes (LEDs). Furthermore, germanium compounds act as polymerization catalysts and are used to produce nanowires. Some germanium compounds, known as organogermanium compounds, are very useful in organometallic chemistry. These diverse uses mean that germanium remains a critical material for advanced technology.

Discovery of the element was a major victory for scientific prediction. In 1869, the Russian chemist Dmitri Mendeleev published his periodic table.

Mendeleev 1869 prediction of germanium (detail)
Mendeleev 1869 prediction of germanium (detail)

He noticed a gap in the carbon family between silicon and tin. He predicted a new element existed there and called it ekasilicon. Mendeleev even estimated its atomic weight would be around 70.

medeleeff by repin
medeleeff by repin

His mathematical predictions were remarkably accurate, as the actual atomic weight was later found to be approximately 72.32.

Clemens Winkler officially discovered the element in 1886 at Freiberg University.

Winkler Clemens
Winkler Clemens

He found germanium while analyzing a mineral called argyrodite, which contains silver and sulfur. Winkler initially thought the element was eka-antimony, but he soon realized it was actually eka-silicon. He originally wanted to name it neptunium to honor the planet Neptune. However, that name was already taken by another proposed element. Instead, he named it germanium after his home country, Germany. He later confirmed its properties using 500 kg of ore from mines in Saxony.

Germanium is primarily mined from sphalerite, which is the main ore of zinc. It can also be recovered from silver, lead, and copper ores. This makes it much harder to supply than silicon. While silicon is abundant in quartz and sand, germanium depends on specific ore availability. This scarcity makes it a strategic material. In 1987, the US government designated it as a critical material for national defense. In 1998, the price of germanium was nearly $800 per kg, while silicon cost less than $10 per kg.

Physically, germanium has some very interesting behaviors. Like silicon, gallium, and water, it expands when it freezes from a molten state. In its standard form, known as alpha-germanium, it has a diamond cubic crystal structure. Under extremely high pressures above 120 kbar, it changes into a metallic form called beta-germanium. One strange phenomenon is the growth of germanium whiskers. These are tiny, spontaneous extrusions that can cause electrical shorts in older electronic components. Despite these challenges, germanium remains a fundamental building block of modern science.

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🖼️ Images & Media (9)
File:medeleeff by repin.jpg
medeleeff by repin.jpg
File:Winkler Clemens.jpg
Winkler Clemens.jpg
File:Mendeleev 1869 prediction of germanium (detail).svg
Mendeleev 1869 prediction of germanium...
File:Winkler preparate 1886 1904.png
Winkler preparate 1886 1904.png
File:Germane-2D-dimensions.svg
Germane-2D-dimensions.svg
File:NucleophilicAdditionWithOrganogermanium.png
NucleophilicAdditionWithOrganogermanium.png
File:Renierit.JPG
Renierit.JPG
File:Singlemode fibre structure.svg
Singlemode fibre structure.svg
File:Pet Flasche.JPG
Pet Flasche.JPG
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