English 
Abstract: This article mainly introduces the chemical properties, physical properties, and application fields of germanium, demonstrating its wide and important application value in multiple fields and emphasizing the need to focus on sustainable resource utilization and environmental protection during its development and application.
Here is content list:
Chemical Properties of Germanium
Physical Properties of Germanium
Application Field of Germanium
Chemical Stability: Germanium has relatively good chemical stability and does not readily react vigorously with most acids and alkalis at room temperature. However, under high temperature, in the presence of strong oxidants or specific conditions, germanium can undergo chemical reactions to form corresponding compounds. For example, it can react with chlorine gas to produce germanium tetrachloride and with oxygen to form germanium dioxide.
Semiconductor Characteristics: This is one of the most prominent properties of germanium and the basis for its wide application in the electronics industry. Germanium's semiconductor property is manifested in that its electrical conductivity lies between that of conductors and insulators, and its electrical properties can be precisely controlled by means such as doping, enabling the manufacture of various semiconductor devices like diodes and transistors.
Appearance and Morphology: Germanium is a grayish-white brittle metal with a metallic luster. At room temperature, it is in a solid state, and its crystal structure is of the diamond type.
Density and Hardness: The density of germanium is approximately 5.323 g/cm³, which is relatively high. Its hardness is moderate, with a Mohs hardness of about 6.0, which means specific techniques and tools are required during its processing.
Melting Point and Boiling Point: Germanium has a melting point of 938.25 °C and a boiling point of 2833 °C. The relatively high melting and boiling points indicate that germanium has good thermal stability and can maintain the relative stability of its physical and chemical properties in high-temperature environments, which provides possibilities for its application in high-temperature fields.
Optical Properties: Germanium has good transparency in the infrared light region and a low absorption rate for infrared light with a wavelength of 1.8 - 20 micrometers. This property makes germanium an ideal material for manufacturing infrared optical devices, such as infrared lenses and infrared windows, which are widely used in military and civilian fields such as infrared thermal imaging, infrared remote sensing, and infrared guidance.
Electronics Industry: Based on its excellent semiconductor properties, germanium was a key material for the early manufacturing of semiconductor devices. In the early days of transistor invention, germanium transistors were widely used in electronic devices such as radios and televisions, promoting the rapid development of electronic technology. Although silicon has dominated most semiconductor applications with the continuous progress of silicon material technology, germanium still plays an irreplaceable role in certain specific fields. For example, in the high-speed and high-frequency communication fields, germanium-based semiconductor devices can provide better performance and are suitable for manufacturing microwave transistors and photodetectors.
Optical Field: Due to its good transparency to infrared light, germanium plays an important role in the manufacturing of optical instruments. In infrared optical systems, germanium lenses are often used for focusing, imaging, and beam transmission. In the military, devices such as infrared night vision goggles and infrared thermal imagers rely on germanium lenses to capture and detect the infrared radiation of targets for night observation and target identification. In the civilian field, germanium is also used in infrared thermal imaging equipment for fire protection and security monitoring, as well as non-contact temperature measurement instruments in industry. In addition, germanium can be used to manufacture optical amplifiers in optical fiber communication. By doping rare earth elements (such as erbium), it can amplify optical signals, compensate for the loss of signals during fiber transmission, and extend the communication distance.
Solar Cells: Germanium has potential application value in the field of high-efficiency solar cells. In the structure of multi-junction solar cells, germanium is often used as the bottom cell material. Due to its relatively narrow bandgap energy, it can absorb long-wavelength sunlight. The multi-junction cell structure composed of materials such as gallium arsenide on the upper layer can make fuller use of the solar spectrum and improve the photoelectric conversion efficiency of solar cells. Such high-efficiency solar cells have important application prospects in fields with high requirements for energy efficiency, such as space exploration and satellite communication.
Pharmaceutical and Health Care Field: Organic germanium compounds have attracted widespread attention in the pharmaceutical and health care aspects. Some studies have shown that organic germanium with specific structures has certain physiological activities and may have potential effects such as antioxidant, immunity enhancement, and anti-tumor. For example, carboxyethyl germanium sesquioxide (Ge - 132) has been studied for the adjuvant treatment of cancer, but the relevant research is still in the exploratory stage, and its exact mechanism of action and clinical efficacy have not been fully clarified. In the health care product market, there are also some products claiming to contain organic germanium components and claiming to have health care effects, but consumers should be cautious when choosing and follow scientific evidence and professional advice.
Other Fields: Germanium also has certain applications in fields such as chemical catalysts and the metallurgical industry. In some organic synthesis reactions, germanium compounds can be used as catalysts to promote the progress of reactions and improve the selectivity and yield of reactions. In the metallurgical industry, germanium can be used to improve the properties of metal materials, such as increasing the strength, hardness, and corrosion resistance of alloys.
