Oxygen is a key element facilitating life and one of the earth's most prominent elements. However, its presence or absence is yet to be confirmed inside the earth's inner core. According to SciTechDaily, the earth's inner core is filled with close to full iron and is subject to high temperature and pressure conditions.
According to Prensa Latina, a recent study showed that oxygen could be present within the earth's solid inner core.
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The Mystery of Earth's Inner Core
According to the scientists of the Innovation study, Fe-O alloys that are Fe-rich can maintain stability in extreme pressures (up to 300 GPa) and temperatures that exceed 3,000 degrees Kelvin.
Prensa Latina reports how it is presently thought that the inner core is filled with light elements. However, the specific content and type are still being studied and debated. Based on cosmochemical and geochemical evidence, this core could be full of silicon, hydrogen, carbon, and sulfur. Calculations and experiments verified how such elements combine with full iron to come up with different iron alloys within high-pressure and high-temperature environments within the earth's deep core.
The inner core of the earth is one of the earth's most mysterious areas, according to Phys. It has the most extreme pressure and temperature conditions on earth.
Phys notes that oxygen is usually not included in the inner core. Such is the case primarily because Fe-O alloys rich in iron were never spotted within the surface or mantle areas. Oxygen levels across all known iron oxides exceed or are equivalent to 50 atomic percent. Though several individuals have been attempting to synthesize compounds of iron oxide that are rich in iron, these substances were never found before.
Oxygen Could Be Present Within the Earth's Core
Researchers conducted various calculations and experiments to see if the earth's inner core was anoxic. In order to mirror the pressure and temperature of the core, iron oxide and pure iron were added to two diamond anvil tips and heated using a laser beam with high energy. After several tries, it was discovered that iron and iron oxide have a chemical reaction that takes place beyond 220-260 GPa and 3,000 degrees Kelvin. The XRD findings show that such reaction products differ from the usual structure of iron oxide and pure iron within high temperatures and pressures.
With a crystal structure search that is theoretical and that uses a genetic algorithm, the scientists proved that such alloys might stably exist at around 200 GPa. Within these conditions, such alloys come up with a hexagonal close-packed structure, where layers of oxygen are arranged between iron layers for the structure to stabilize. This mechanism leads to several close-packed arrangements, coming up with a large Fe-O compound family that is Fe-rich and has a configurational entropy.
According to such theoretical data, an iron oxide atomic configuration was seen to match the XRD pattern that was experimentally gauged. Even more, calculations revealed that iron-rich Fe-O phases are also metallic. The structure or electrons depend on the concentration of O and the layer arrangements of both iron and oxygen.
Alloy's mechanical and thermal properties need to be further investigated.
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