Platinum group elements osmium

Rauch, S., Hemond, H.F., Peucker-Ehrenbrink, B. Recent changes in platinum group element concentrations and osmium isotopic composition in sediments from an urban lake. Environ. Sci. Technol. 38, 396-402 (2004)... 

Hattori H. and Hart S. R. (1991) Osmium isotope ratios of platinum group elements associated with ultramafic intrusions. Earth. Planet. Sci. Lett. 107, 499-514. 

Peucker-Ehrenbrink B. and Jahn B.-M. (2001) Rhenium-osmium isotope systematics and platinum group element concentrations loess and the upper continental crust. Geochem. Geophys. Geosys. G 3 2001GC000172. 

Cave R. R., Ravizza G. E., German C. R., Thomson J., and Nesbitt R. W. (2003) Deposition of osmium and other platinum-group elements beneath the ultramafic-hosted rainbow hydrothermal plume. Earth Planet. Sci. Lett. 210, 65-79. 

There are characteristic chemical properties of cosmic dust that have been involved in the study of sediment accumulation rates. The platinum group elements, such as iridium and osmium, offer good examples. Attempts to use iridium in this way have had the important result of indicating a giant meteorite impact at the Cretaceous-Tertiary boundary (Alvarez et ai, 1980) but it has not been proven important in determining chronometry. 

Osmium forms relatively few non-organoraetallic metal-metal-bonded complexes (for species containing Os—Hg bonds see above, p. 525). In common with the other platinum group elements, however, it does form species of the type [Os(SnX3)5Xf -, and these have received some recent study. 

Rauch S, Hemond HF, Peuker-Ehrenbrink B, Ek KH, Morrison GM (2005) Platinum group element concentrations and osmium isotopic composition in urban airborne particles from Boston, Massachusetts. Env Sci Technol 39 9464—9470 Ravindra K, Bencs L, Van Grieken R (2004) Platinum group elements in the environment and... 

The platinum-group metals (PGMs), which consist of six elements in Groups 8— 10 (VIII) of the Periodic Table, are often found collectively in nature. They are mthenium, Ru rhodium, Rh and palladium, Pd, atomic numbers 44 to 46, and osmium. Os indium, Ir and platinum, Pt, atomic numbers 76 to 78. Corresponding members of each triad have similar properties, eg, palladium and platinum are both ductile metals and form active catalysts. Rhodium and iridium are both characterized by resistance to oxidation and chemical attack (see Platinum-GROUP metals, compounds). 

Ruthenium also belongs to the platinum group, which includes six elements with similar chemical characteristics. They are located in the middle of the second and third series of the transition elements (groups 8, 9, and 10). The platinum group consists of ruthenium, rhodium, palladium, osmium, iridium, and platinum. 

Osmium is found in group 8 (VIII) of the periodic table and has some of the same chemical, physical, and historical characteristics as several other elements. This group of similar elements is classed as the platinum group, which includes Ru, Rh, and Pd of the second transition series (period 5) and Os, Ir, and Pt of the third series of transition metals (period 6). 

Os forms many complexes with nitnte. oxalate, carbon monoxide, amines, and thio ureas. The latter arc important analytically Osmium forms the interesting aromatic sandwich" compound, osmocene. A metallocene is described under Ruthenium. See also Chemical Elements and Platinum and Platinum Group. 

As its title implies, this review restricts itself to describing and discussing compounds of platinum group metals—i.e., of ruthenium, rhodium, palladium, osmium, iridium, and platinum—although the compounds of the other transition elements and even some post-transition elements are either fully analogous or closely related to those of the platinum metals. 

Osmium bears a close resemblance to ruthenium in many of its chemical properties in fact, in certain respects, such as the formation of tetroxides, these two elements are absolutely unique amongst the metals of the platinum group. 

---