Pure Germanium is a hard, lustrous, gray-white, brittle metalloid. It has a
diamondlike crystalline structure and it is similar in chemical and physical
properties to Silicon. Germanium is stable in air and water, and is unaffected
by alkalis and acids, except nitric acid.
Applications
Germanium is an important semiconductor, mainly used in transistors and
integrated circuits. They are often made from Germanium to which small amounts
of Arsenic, Gallium, or other metals. Germanium forms many compounds. Germanium
oxide is added to glass to increase the index of refraction; such glass is used
in wide-angle lenses and in infrared devices. Numerous alloys containing
Germanium have been prepared. High purity Germanium single crystal detectors can
precisely identify radiation sources (e.g. for airport security).
Germanium in the environment
Germanium is less abundant than either tin or lead, which are the heavier
component metals of group 14, and it is less easily accessed because geological
processes have contracted only small amounts of it into minerals, so that it
tends to be widely dispersed. Germanium ores are rare. The least rare,
germanite, is a Copper-Iron-Germanium sulfide with 8% of the element, but even
this is not mined. Germanium is widely distributed in ores of other metals, such
as Zinc, and that which is required for manufacturing purposes is recovered as a
by-product from the flue-dusts of Zinc smelters. World production is about 80
tonnes per year.
Health effects of Germanium
The estimated daily intake is around 1 mg, and there have been claims that
Germanium could be beneficial to health, athough this has never been proved
scientifically. A high intake of Germanium was supposed to improve the immune
system, bost the body's Oxygen supply, make a person feel more alive and destroy
damaging free radicals. In addition was said to protect the user against
radiation. In 1989 in the UK the Governement's Department of Health warned
against Germanium supplements, noting that they had no nutritional or medical
value and that taking them consituted a risk to health, rather than a benefit.
Germanium hydride and Germanium tetrahydride are extremely flammable and even
explosive when mixed with air. Inhalation: Abdominal cramps. Burning sensation.
Cough. Skin: Redness. Pain. Eyes: Redness. Pain.
Routes of exposure: The substance can be absorbed into the body by inhalation.
Inhalation risk: A harmful concentration of this gas in the air will be reached
very quickly on loss of containment.
Effects of short-term exposure: The substance irritates the eyes, the skin and
the respiratory tract. The substance may cause effects on the blood, resulting
in lesions of blood cells. Exposure may result in death.
Environmental effects of Germanium
Physical dangers: The gas is heavier than air and may travel along the ground;
distant ignition possible.
As a heavy metal it is considered to have some negative impact in aquatic
ecosystems.
