Nickel earth core

Birch (1952) compared seismically determined density estimates for the mantle and core with the available EOS data for candidate materials. He argued that the inner core was a crystalline phase, mainly iron and the liquid outer core is perhaps some 10-20% less dense than that expected for iron or iron-nickel at core conditions. Later, Birch (1964) showed that the Earth s outer core is —10% less dense than that expected for iron at the appropriate pressures and temperatures and proposed that it contained (in addition to liquid iron and nickel) a lighter alloying element or elements such as carbon, or hydrogen (Birch, 1952) or sulfur, silicon, or oxygen (Birch, 1964). 

The many expeditions to Venus have also produced a good deal of information about the planet s surface and interior structure and composition. The overall structure of the planet is probably similar to that of Earth, consisting of a large central core about 2,000 miles (3,000 km) in radius, made of liquid iron and nickel. The core is probably surrounded by a molten mantle, consisting of rocky material that is, in turn, covered by a thin, solid outer surface. Many... 

Earths core is a solid iron sphere about the size of the Moon. Surrounding the inner core, there is an outer liquid core that contains a nickel-iron alloy. Scientists think the iron core formed when multiple collisions during Earths early history resulted in enough heat to melt metals. In the molten state, the densest materials, including iron and nickel, settled to the center and became Earths core. The less-dense materials remained at the surface. As Earth cooled, the outer layers solidified, creating Earths mantle and crust. 

Occurrence. Iron is highly abundant (about 5.5% of the earth s crust) it is believed that the core of earth is mostly molten iron together with nickel. The most common ore is haematite (Fe203). Iron is found in other minerals such as magnetite, limonite, siderite, pyrite. Iron is found native in meteorites known as siderites. 

Iron is the fourth most abundant element in the Earths crust (about 5%) and is the ninth most abundant element found in the sun and stars in the universe. The core of the Earth is believed to consist of two layers, or spheres, of iron. The inner core is thought to be molten iron and nickel mixture, and the outer core is a transition phase of iron with the molten magma of the Earths mantle. 

Nickel is the 23rd most abundant element found in the Earths crust. It is somewhat plentiful but scattered and makes up one-hundredth of 1% of igneous rocks. Nickel metal is found in meteorites (as are some other elements). It is believed that molten nickel, along with iron, makes up the central sphere that forms the core of the Earth. 

The abundance of nickel in the earth s crust is only 84 mg/kg, the 24 most abundant element. It is found in most meteorites, particularly in the iron meteorites or siderites, alloyed with iron. Its average concentration in seawater is 0.56 pg/mL. Nickel is one of the major components of the earth s core, comprising about 7%. 

Nickel is also found in meteorites and on the ocean floor in lumps of minerals known as sea floor nodules. The earth s core contains large amounts of nickel. Nickel is released into the atmosphere during nickel mining and by industries that make alloys or nickel compounds or industries that use nickel and its compounds. These industries may also discharge nickel in waste water. Nickel is also released into the atmosphere by oil-burning power plants, coalburning power plants, and trash incinerators. 

The Earth s core is composed of iron-nickel alloy, with an inner solid core surrounded by a molten outer core. A mismatch between the inferred density of the outer core and that predicted for iron-nickel metal at high pressure suggests that some light elements) must dilute the iron in the molten core. Some possibilities are oxygen, sulfur, silicon, and hydrogen, all elements with high cosmic abundances that can alloy with iron at very high... 

Chabot, N. L., Draper, D. S. and Agee, . B. (2005) Conditions of core formation in the Earth constraints from nickel and cobalt partitioning. Geochimica et Cosmochimica Acta, 69,2141-2151. 

Core (Earth) A spherical nickel-iron body at the center of the Earth. The core is divided into inner and outer sections. The outer core is a molten iron-nickel layer at about 2900 to 5100 km below the Earth s surface. The inner core is the central shell of the Earth, which is solid and extends from a depth of about 5100 km to the very center of the Earth at a depth of 6370 km. 

Crystal field theory is one of several chemical bonding models and one that is applicable solely to the transition metal and lanthanide elements. The theory, which utilizes thermodynamic data obtained from absorption bands in the visible and near-infrared regions of the electromagnetic spectrum, has met with widespread applications and successful interpretations of diverse physical and chemical properties of elements of the first transition series. These elements comprise scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel and copper. The position of the first transition series in the periodic table is shown in fig. 1.1. Transition elements constitute almost forty weight per cent, or eighteen atom per cent, of the Earth (Appendix 1) and occur in most minerals in the Crust, Mantle and Core. As a result, there are many aspects of transition metal geochemistry that are amenable to interpretation by crystal field theory. 

Iron meteorites consist mainly of iron and nickel. They resemble material thought to lie deep in the cores of some planets, including Earth. This suggests that iron meteorites may be chunks from the core of a larger body that broke apart. 

Iron is the second most abundant metal after A1 and the fourth most abundant element in the earth s crust. The earth s core is believed to consist mainly of iron and nickel, and the occurrence of iron meteorites suggests that it is abundant throughout the solar system. The major iron ores are hematite (Fe203), magnetite (Fe304), limonite [FeO(OH)], and siderite (FeC03). 

The mean density of Mercury is 5.43 0.01 g cm (Anderson et al., 1987). This corresponds to a reduced (or uncompressed) density of 5.31 (Kaula, 1986). The reduced density is the density a planet would have if it was not compressed, but was at high enough pressure to squeeze out all the pore spaces, —10 kbar (Kaula, 1986). Calculation of the reduced densities of the terrestrial planets assumes that the core is composed of iron and nickel, and that all the metal is in the core. The reduced density of Mercury is by far the largest of the terrestrial planets. Earth is the closest, with a reduced density of only 4.03 g cm. ... 

The six most abundant, nonvolatile rock-forming elements in the Sun are Si (100), Mg (104), Fe (86), S (43), Al (8.4), and Ca (6.2). The numbers in parentheses are atoms relative to 100 Si atoms. They are derived from element abundances in Cl-meteorites which are identical to those in the Sun except that Cl-abundances are better known (see Chapter 1.03). From geophysical measurements it is known that the Earth s core accounts for 32.5% of the mass of the Earth. Assuming that the core contains only iron, nickel, and sulfur allows us to calculate the composition of the silicate fraction of the Earth by mass balance. This is the composition of the bulk silicate earth (BSE) or the primitive earth mantle (PM). The term primitive implies the composition of the Earth s mantle before crust and after core formation. 

Gessmann C. K. and Rubie D. C. (1998) The effect of temperature on the partitioning of nickel, cobalt, manganese, chromium and vanadium at 9 GPa and constraints on formation of the Earth s core. Geochim. Cosmochim. Acta 62, 867-882. 

Li J. and Agee C. B. (2001) The effect of pressure, temperature, oxygen fugacity and composition on partitioning of nickel and cobalt between liquidFe—Ni—S alloy and liquid silicate implications for the Earth s core formation. Geochim. Cosmochim. Acta 65, 1821—1832. 

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