GERMANIO

Germanium

A chemical element between silicon and tin in Group 14 (IVa) of the periodic table, a silvery-gray metalloid, intermediate in properties between the metals and the nonmetals. Although germanium was not discovered until 1886 by Clements Winkler, a German chemist, its existence, properties, and position in the periodic system had been predicted in 1871 by the Russian chemist Dmitry Ivanovic Mendeleyec, who called the hypothetical element ekasilicon. Germanium did not become economically significant until after 1945, when its properties as a semiconductor were recognized as being of value in electronics. Many other substances now also are used as semiconductors, but germanium remains of primary importance in the manufacture of transistors and of components for devices such as rectifiers and photocells.

In addition to its applications in electronic devices, germanium is used as a component of alloys and in phosphors for fluorescent lamps. Because germanium is transparent to infrared radiation, it is employed in equipment used for detecting and measuring such radiation, such as windows and lenses. The high index of refraction of germanium dioxide renders it valuable as a component of glasses used in optical devices, such as wide-angle lenses for cameras and microscope objectives. The toxicology of germanium and its compounds is poorly defined.

Blanks ready to be fulfilled...A genious job

In 2019, it was celebrated the 150th anniversary of Dmitri Mendeleyev’s Periodic Table of elements. Categorizing them into a perfect order, was an mind blowing achievement. Silicon was known to Mendeleyev, but its "cousin" germanium was not. Mendeleyev could see there should be another element in the table’s order. Since he did not know what that element is, he left that place blank. Germanium was finally discovered by the German chemist Clemens Winkler some 15 years later as it was written before.

But the search for the missing element would not have taken place so fast had the empty space in the Periodic Table not been left blank. That blank space inspired other scientists to go looking for the element that will fill that blank place.

"In a dream I saw a table where all the elements fell into place as required. Awakening, I immediately wrote it down on a piece of paper"

Scandium, Gallium, Germanium were the three elements predicted by Mendeleev with blanks in his periodic table (of course they were known by him with another names...eka-boron, eka-aluminium, eka-silicon, being eka a prefix used to designate the first element of the same family in the periodic table). But the genious went much further, he proposed that some of the elements, whose behavior did not agree with his predictions, must have had their atomic weights measured incorrectly (take into account that the criteria to order elements chosen by him was precisely the atomic weight). It turned out that chemists had measured some atomic weights incorrectly as it was found out a little bit later. Mendeleev was right!

Powering up space stations with germanium-based solar cells

Six next-gen roll-out solar arrays (ROSAs). That’s what’s needed to help ensure the International Space Station (ISS) can support continued operations through 2030. The secret ingredient? Multi-junction solar cells based on germanium substrates. These enable more efficient energy conversion, protect better against space radiation and have a lower total cost. No wonder NASA will equip the Gateway, a future outpost orbiting the moon, with a similar solution.

How do we know that germanium lives up to the test when it comes to space exploration?

Compared to the old generation of solar arrays, the new ROSAs offer great advantages:

• Because they are smaller and can be rolled up, it’s easier and less costly to launch them into space.

• The germanium-based solar cells convert up to twice as much light into electricity as their silicon-based counterparts.

• Since germanium is more resistant to damaging cosmic radiation than silicon, the solar cells’ lifespan can be extended from 15 to 20 years.

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