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Osmium compounds AI simulator
(@Osmium compounds_simulator)
Hub AI
Osmium compounds AI simulator
(@Osmium compounds_simulator)
Osmium compounds
Osmium compounds are compounds containing the element osmium (Os). Osmium forms compounds with oxidation states ranging from −2 to +8. The most common oxidation states are +2, +3, +4, and +8. The +8 oxidation state is notable for being the highest attained by any chemical element aside from iridium's +9 and is encountered only in xenon, ruthenium, hassium, iridium, and plutonium. The oxidation states −1 and −2 represented by the two reactive compounds Na
2[Os
4(CO)
13] and Na
2[Os(CO)
4] are used in the synthesis of osmium cluster compounds.
Osmium tetroxide is the most notable compound of osmium, having many uses. The name "osmium" even derives from Greek "ὀσμή, osme, 'smell'" because of the smell of osmium tetroxide. It also has a number of unusual properties, one being that the solid is volatile. Its volatility, along with its strong oxidizing power, is the origin of its quite serious toxicity - inhalation provides a very effective route for the compound to react with tissue. The compound is colourless, but most samples appear yellow. This is most likely due to the presence of the impurity OsO2, which is yellow-brown in colour. In biology, its property of binding to lipids has made it a widely used stain in electron microscopy. OsO4 is formed slowly when osmium powder reacts with O2 at ambient temperature. Reaction of bulk solid requires heating to 400 °C.
OsO4 is a Lewis acid and a mild oxidant. It reacts with alkaline aqueous solution to give the perosmate anion OsO
4(OH)2−
2. This species is easily reduced to osmate anion, OsO
2(OH)2−
4. When the Lewis base is an amine, adducts are also formed. Thus OsO4 can be stored in the form of osmeth, in which OsO4 is complexed with hexamine. Osmeth can be dissolved in tetrahydrofuran (THF) and diluted in an aqueous buffer solution to make a dilute (0.25%) working solution of OsO4. With tert-BuNH2, the imido derivative is produced:
Similarly, with NH3 one obtains the nitrido complex:
The [Os(N)O3]− anion is isoelectronic and isostructural with OsO4. OsO4 is very soluble in tert-butyl alcohol. In solution, it is readily reduced by hydrogen to osmium metal. The suspended osmium metal can be used to catalyze hydrogenation of a wide variety of organic chemicals containing double or triple bonds.
OsO4 undergoes "reductive carbonylation" with carbon monoxide in methanol at 400 K and 200 sbar to produce the triangular cluster Os3(CO)12:
Osmium dioxide is another known oxide of osmium, which can be obtained by the reaction of osmium with a variety of oxidizing agents, including, sodium chlorate, osmium tetroxide, and nitric oxide at about 600 °C. It does not dissolve in water, but is attacked by dilute hydrochloric acid. The crystals have rutile structure. Unlike osmium tetroxide, OsO2 is not toxic.
Osmium hexafluoride is one of the 17 known binary hexafluorides, which can be made by the direct reaction of osmium metal exposed to an excess of elemental fluorine gas at 300 °C. It is a yellow crystalline solid that melts at 33.4 °C and boils at 47.5 °C. The solid structure measured at −140 °C is orthorhombic space group Pnma. Lattice parameters are a = 9.387 Å, b = 8.543 Å, and c = 4.944 Å. There are four formula units (in this case, discrete molecules) per unit cell, giving a density of 5.09 g·cm−3. The OsF6 molecule itself (the form important for the liquid or gas phase) has octahedral molecular geometry, which has point group (Oh). The Os–F bond length is 1.827 Å. Partial hydrolysis of OsF6 produces OsOF4. Osmium pentafluoride is a tetramer in the solid state that can be prepared by reduction of osmium hexafluoride with iodine as a solution in iodine pentafluoride:
Osmium compounds
Osmium compounds are compounds containing the element osmium (Os). Osmium forms compounds with oxidation states ranging from −2 to +8. The most common oxidation states are +2, +3, +4, and +8. The +8 oxidation state is notable for being the highest attained by any chemical element aside from iridium's +9 and is encountered only in xenon, ruthenium, hassium, iridium, and plutonium. The oxidation states −1 and −2 represented by the two reactive compounds Na
2[Os
4(CO)
13] and Na
2[Os(CO)
4] are used in the synthesis of osmium cluster compounds.
Osmium tetroxide is the most notable compound of osmium, having many uses. The name "osmium" even derives from Greek "ὀσμή, osme, 'smell'" because of the smell of osmium tetroxide. It also has a number of unusual properties, one being that the solid is volatile. Its volatility, along with its strong oxidizing power, is the origin of its quite serious toxicity - inhalation provides a very effective route for the compound to react with tissue. The compound is colourless, but most samples appear yellow. This is most likely due to the presence of the impurity OsO2, which is yellow-brown in colour. In biology, its property of binding to lipids has made it a widely used stain in electron microscopy. OsO4 is formed slowly when osmium powder reacts with O2 at ambient temperature. Reaction of bulk solid requires heating to 400 °C.
OsO4 is a Lewis acid and a mild oxidant. It reacts with alkaline aqueous solution to give the perosmate anion OsO
4(OH)2−
2. This species is easily reduced to osmate anion, OsO
2(OH)2−
4. When the Lewis base is an amine, adducts are also formed. Thus OsO4 can be stored in the form of osmeth, in which OsO4 is complexed with hexamine. Osmeth can be dissolved in tetrahydrofuran (THF) and diluted in an aqueous buffer solution to make a dilute (0.25%) working solution of OsO4. With tert-BuNH2, the imido derivative is produced:
Similarly, with NH3 one obtains the nitrido complex:
The [Os(N)O3]− anion is isoelectronic and isostructural with OsO4. OsO4 is very soluble in tert-butyl alcohol. In solution, it is readily reduced by hydrogen to osmium metal. The suspended osmium metal can be used to catalyze hydrogenation of a wide variety of organic chemicals containing double or triple bonds.
OsO4 undergoes "reductive carbonylation" with carbon monoxide in methanol at 400 K and 200 sbar to produce the triangular cluster Os3(CO)12:
Osmium dioxide is another known oxide of osmium, which can be obtained by the reaction of osmium with a variety of oxidizing agents, including, sodium chlorate, osmium tetroxide, and nitric oxide at about 600 °C. It does not dissolve in water, but is attacked by dilute hydrochloric acid. The crystals have rutile structure. Unlike osmium tetroxide, OsO2 is not toxic.
Osmium hexafluoride is one of the 17 known binary hexafluorides, which can be made by the direct reaction of osmium metal exposed to an excess of elemental fluorine gas at 300 °C. It is a yellow crystalline solid that melts at 33.4 °C and boils at 47.5 °C. The solid structure measured at −140 °C is orthorhombic space group Pnma. Lattice parameters are a = 9.387 Å, b = 8.543 Å, and c = 4.944 Å. There are four formula units (in this case, discrete molecules) per unit cell, giving a density of 5.09 g·cm−3. The OsF6 molecule itself (the form important for the liquid or gas phase) has octahedral molecular geometry, which has point group (Oh). The Os–F bond length is 1.827 Å. Partial hydrolysis of OsF6 produces OsOF4. Osmium pentafluoride is a tetramer in the solid state that can be prepared by reduction of osmium hexafluoride with iodine as a solution in iodine pentafluoride: