Lower oxidation states nitrate

Another method of preparing pure nitric oxide is to heat nitrate-nitrite mixture with a metal oxide in a lower oxidation state ... 

B. Milligan, Nitration of Aromatics hy Lower Oxidation States of Nitrogen, J. Org. Chem. 48, 1495 (1983). 

Uranium Compounds with Lower Oxidation States. Pour 5 ml of a uranyl nitrate solution into a test tube, add 1 ml of a 10% hydrochloric acid solution, and drop one or two small pieces of zinc into the tube. How can the change in the solution s colour be explained Pour the solution into three test tubes. Pour a potassium permanganate solution dropwise into one tube. What happens What properties do uranium(lV) compounds have ... 

The methods listed yield the concentrations either of water-soluble ions measured in terms of certain oxidized states or of elements. For example, materials appearing as sulfate and nitrate may include lower oxidation states, but the methods basically do not distinguish among them. The metal elements found are either oxides or soluble salts. The actual composition of the material is indeterminant, but workers have deduced the composition suspected to be present by a material balance, combined with knowledge of the origins of the particulate material. 

Compared with other transition metals in biological redox systems, the oxidation states likely to be used by molybdenum are very high (74). As discussed previously, the IV, V, and VI states are a likely set of participants in molybdenum oxidases, and while the II and III states remain viable for molybdenum reductases, it nevertheless seems likely that higher oxidation states will be found in these enzymes as well. Indeed, the substitution of tungsten for molybdenum in both nitrate reductase and nitrogenase indicates this likelihood as it is much more difficult to obtain the lower oxidation states of tungsten. 

Actinides Generally present in fully oxidized form, but salts such as nitrates, fluorides, and chlorides are common in solution Fully oxidized forms are insoluble. Oxides of lower oxidation states may be slightly soluble. Actinide salts are soluble... 

Plutonium is a very reactive metal and oxidizes readily in moist air. In finely divided form, plutonium metal is pyrophoric (Taylor 1973). Plutonium exhibits five oxidation states from plutonium(lll) to plutonium(VII). The four lower oxidation states are stable in solution and may co- exist in the same solution. Complex (coordination) compounds are formed with many of the common inorganic anions, such as plutonium nitrate (Pu(NO 3) 4). 

Metal nitrates readily undergo bond homolysis to form metal oxides. A survey of the CID reactions of metal nitrate anions, [Metal (N03)x+i] , with different oxidation states (x = 1-3) revealed the following competing fragmentation pathways NO2 loss to form a metal oxide (Eq. (6.85)), NO3 loss with reduction of the metal center (Eq. (6.86)), formation of the nitrate anion, N03 (Eq. (6.87)), and loss of two NO2 neutrals (Eq. (6.88)). An examination of Table 6.2 reveals that the types of reactions observed depend on both the metal and its oxidation state. For the two metals (Cu and Fe) that were studied in two different oxidation states, CID of the higher oxidation state results in NO3 loss with reduction of the metal to the lower oxidation state (Eq. (6.86)). This reaction does not occur for the lower oxidation state, which instead gives N—O bond homolysis via loss of NO2 (Eq. (6.85)). 

The N,F, assay consists of three steps (1) digestion with alkaline permanganate solution to decompose the material, (2) acidification and treatment with sodium bisulphite to reduce the manganese and iodine to their lower oxidation states and (3) titration with silver nitrate. 

Nitrate reduction by which nitrogen in chemical compounds is reduced by microbial action to lower oxidation states in the absence of fi ee oxygen ... 

Nitric acid is also a good oxidizing agent. For example, copper reacts with dilute HN03(aq), producing primarily NO or, with concentrated HN03(aq), NO2 (reaction 22.43). With a more active metal, such as Zn, the reduction product has N in one of its lower oxidation states, for example, NH4. Nitrates can be made by neutralizing nitric acid with appropriate bases. 

The reduction of NOs" to NH4" is catalyzed sequentially by nitrate reductase and a series of further reductions to lower oxidation states by nitrate reductase. These reactions together require an input of four electron pairs per mole of nitrate as indicated in reactions (6) and (7) below ... 

MedloCK has latterly patented a method, whereby the nitrates which exert such a powerful action, upon lead are removed, together with the organic matter, if the latter he not present in great excess. It consists in suspending coils of iron wire or pieces of sheet-iron in the water, and after a stated period filtering off the deposit which forms. By this means the nitrie acid is decomposed by the iron,.which Is transformed into sos-quioxlde and falls to the bottom, whilst nitrous gas is set free and Oxidizes the carbonaceous matters, which remain still in the fluid so as to yield carbonic aoid and a lower oxide cf nitrogen. 

When an explosive slowly decomposes, the products may not follow the previously described hierarchy or be at the maximum oxidation states. The nitro, nitrate, nitramines, acids, etc., in an explosive molecule can break down slowly. This is due to low-temperature kinetics as well as the influence of light, infrared, and ultraviolet radiation, and any other mechanism that feeds energy into the molecule. Upon decomposition, products such as NO, NO2, H2O, N2, acids, aldehydes, ketones, etc., are formed. Large radicals of the parent explosive molecule are left, and these react with their neighbors. As long as the explosive is at a temperature above absolute zero, decomposition occurs. At lower temperatures the rate of decomposition is infinitesimally small. As the temperature increases, the decomposition rate increases. Although we do not always, and in fact seldom do, know the exact chemical mechanism, we do know that most explosives, in the use range of temperatures, decompose with a zero-order reaction rate. This means that the rate of decomposition is usually independent of... 

Much less work has been reported for the 6-valent elements as compared with the volume of literature for the actinides in lower valence states. Hydrated neptunium and plutonium trioxides are now known, Np03 H2O and PUO3 (0.8)H2O being readily obtained by the action of ozone on an aqueous suspension of neptunium (V) or plutonium (IV) hydroxides at 90°C. (23) Np03 2H2O is obtained in a similar manner at 18°C. (23) or by ozone oxidation of neptunium (V) in a molten lithium-potassium nitrate eutectic at 150°C. (42). 

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