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Germanium is created by stellar nucleosynthesis, mostly by the s-process in asymptotic giant branch stars. The s-process is a slow neutron capture of lighter elements inside pulsating red giant stars. [55] Germanium has been detected in some of the most distant stars [56] and in the atmosphere of Jupiter. [57]
Germanium (32 Ge) has five naturally occurring isotopes, 70 Ge, 72 Ge, 73 Ge, 74 Ge, and 76 Ge. Of these, 76 Ge is very slightly radioactive, decaying by double beta decay with a half-life of 1.78 × 10 21 years [4] (130 billion times the age of the universe). Stable 74 Ge is the most common isotope, having a natural abundance of approximately ...
The oceanic carbon cycle (or marine carbon cycle) is composed of processes that exchange carbon between various pools within the ocean as well as between the atmosphere, Earth interior, and the seafloor. The carbon cycle is a result of many interacting forces across multiple time and space scales that circulates carbon around the planet ...
The Earth's crust is one "reservoir" for measurements of abundance. A reservoir is any large body to be studied as unit, like the ocean, atmosphere, mantle or crust. Different reservoirs may have different relative amounts of each element due to different chemical or mechanical processes involved in the creation of the reservoir. [1]: 18
Two oxides of germanium are known: germanium dioxide (GeO 2, germania) and germanium monoxide, (GeO). [4] The dioxide, GeO 2 can be obtained by roasting germanium disulfide (GeS 2) or by allowing elemental germanium to slowly oxidze in air, [5] and is a white powder that is only slightly soluble in water but reacts with alkalis to form germanates. [4]
Germanium dioxide, also called germanium (IV) oxide, germania, and salt of germanium, [1] is an inorganic compound with the chemical formula Ge O 2. It is the main commercial source of germanium. It also forms as a passivation layer on pure germanium in contact with atmospheric oxygen.
Today, the average time that an O 2 molecule spends in the air before it is consumed by geological sinks is about 2 million years. [61] That residence time is relatively short in geologic time; so in the Phanerozoic, there must have been feedback processes that kept the atmospheric O 2 level within bounds suitable for animal life.
In meteorology, an air mass is a volume of air defined by its temperature and humidity. Air masses cover many hundreds or thousands of square miles, and adapt to the characteristics of the surface below them. They are classified according to latitude and their continental or maritime source regions. Colder air masses are termed polar or arctic ...