Skutterudite is a naturally occurring cobalt arsenide mineral. The crystal structure of this mineral has been found to have important technological uses for several compounds isostructural with the mineral. General Name, Symbol, Number cobalt, Co, 27 Chemical series transition metals Group, Period, Block 9, 4, d Appearance metallic with gray tinge Atomic mass 58. ... An arsenide ion is an arsenic atom with three extra electrons and charge -3. ... This article is about minerals in the geologic sense; for nutrient minerals see dietary mineral; for the band see Mineral (band). ... Rose des Sables (Sand Rose), formed of gypsum crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... A chemical compound is a chemical substance formed from two or more elements, with a fixed ratio determining the composition. ...

The skutterudite mineral

Skutterudite from Bou Azzer, Morocco.

Skutterudite is a cobalt arsenide mineral that has variable amounts of nickel and iron substituting for cobalt with a general formula: (Co,Ni,Fe)As₃. Some references give the arsenic a variable formula subscript of 2-3. High nickel varieties are referred to as nickel-skutterudite, previously chloanthite. It is a hydrothermal ore mineral found in moderate to high temperature veins with other Ni-Co minerals. Associated minerals are arsenopyrite, native silver, erythrite, and annabergite. It is mined as an ore of cobalt and nickel with a by-product of arsenic. Photograph of a specimen of Skutterudite specimen taken by Dlloyd. ... Photograph of a specimen of Skutterudite specimen taken by Dlloyd. ... General Name, Symbol, Number cobalt, Co, 27 Chemical series transition metals Group, Period, Block 9, 4, d Appearance metallic with gray tinge Atomic mass 58. ... An arsenide ion is an arsenic atom with three extra electrons and charge -3. ... General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10, 4, d Appearance lustrous, metallic Atomic mass 58. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... Hydrothermal circulation in the oceans is the passage of the water through mid-ocean Ridge (MOR) systems. ... Iron ore (Banded iron formation) Manganese ore Lead ore Gold ore An ore is a mineral deposit containing a metal or other valuable resource in economically viable concentrations. ... Arsenopyrite is an iron arsenic sulfide (FeAsS). ... General Name, Symbol, Number silver, Ag, 47 Chemical series transition metals Group, Period, Block 11, 5, d Appearance lustrous white metal Atomic mass 107. ... Erythrite is a secondary hydrated arsenate of cobalt minerals with the formula (Co3(AsO4)2·8H2O). ... Annabergite is a mineral consisting of a hydrous nickel arsenate, Ni3(AsO4)2 + 8H2O, crystallizing in the monoclinic system and isomorphous with vivianite and erythrite. ... General Name, Symbol, Number arsenic, As, 33 Chemical series metalloids Group, Period, Block 15, 4, p Appearance metallic gray Atomic mass 74. ...

The mineral has a bright metallic luster, and is tin white or light steel gray in color with a black streak. The specific gravity is 6.5 and the hardness is 5.5-6. Its crystal structure is isometric with cube and octahedron forms similar to that of pyrite. The arsenic content gives a garlic odor when heated or crushed. Relative density (also known as specific gravity) is a measure of the density of a material. ... Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer. ... Rose des Sables (Sand Rose), formed of gypsum crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... In crystallography, the cubic crystal system (or isometric crystal system) is the most symmetric of the 7 crystal systems. ... The mineral pyrite, or iron pyrite, is iron disulfide, FeS2. ...

It was discovered in Skutterud, Norway, in 1845. Smaltite is a synonym for the mineral. Notable occurrences include Cobalt, Ontario , Canada, Skutterud, Norway, Franklin, New Jersey in the United States, and in other cobalt and nickel mining areas around the world. The rare arsenide minerals are classified in Dana's sulfide mineral group, even though it contains no sulfur. 1845 was a common year starting on Wednesday (see link for calendar). ... Cobalt is a town in the district of Timiskaming, province of Ontario, Canada, with a population of 1,221, and an area of 2. ... Franklin is a borough located in Sussex County, New Jersey. ... General Name, Symbol, Number cobalt, Co, 27 Chemical series transition metals Group, Period, Block 9, 4, d Appearance metallic with gray tinge Atomic mass 58. ... In chemistry, a sulfide (sulphide in British) is a chemical compound or combination of sulfur with an oxidation number of -2, with another chemical element or a radical thereof. ...

The skutterudite crystal structure

The skutterudite unit cell.

The crystal structure of the skutterudite mineral was determined in 1928 by Oftedahl to be cubic, belonging to space group Im-3 (number 204). The unit cell can be considered to consist of eight smaller cubes made up of the Co atoms. Six of these cubes are filled with (almost) square planar rings of As, each of which is oriented parallel to one of the unit cell edges, see image on the right. The As atoms then form octahedra with Co in the centre. Image File history File linksMetadata Download high resolution version (787x791, 263 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File linksMetadata Download high resolution version (787x791, 263 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... A space group is a mathematical symmetry group or symmetry group type of n-dimensional structures with translational symmetry in n independent directions, such as, for n = 3, a crystal. ... In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ...

In crystallographic terms, the Co atoms occupy the 8c sites, while the As atoms occupy the 24g sites. The position of the Co atoms within the unit cell is fixed, while the positions of the As atoms are determined by the parameters x and y. It has been shown that for the As-rings to be fully square, these parameters must satisfy the Oftedahl relation x+y=1/2. Any deviation from this relation yields a rectangular configuration of the As atoms. Indeed, this is the case for all known compounds with this structure, and it should be noted that the As atoms then do not form perfect octahedra.

Together with the unit cell size and the assigned space group, these two parameters fully describe the crystal structure of the material which is often referred to as the skutterudite structure.

References

• Dana's Manual of Mineralogy ISBN 0471032883
• A. Kjekshus and T. Rakke. Compunds with skutterudite type crystal-structure .3. Structural data for arsenides and antimonides. Acta Chemica Scandinavica Series A 28 (1): 99-103 1974.
• Mineral galleries
• Mindat.org
• Webmineral.com

See also

• List of minerals