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Phosphorus oxyanions

The kinetics of oxidation of bivalent manganese to the heptavalent state by peroxomonophosphoric acid has been investigated/ In perchloric acid, the reaction rate is negligible without the addition of an appropriate catalyst. Trace quantities of Co(II) increase the observed reaction rate significantly the resulting rate law and mechanism are shown in equations (46)-(53). The oxidation was [Pg.89]


The oxyanions Sn044 and Sn032- are both considered to be stannates because they contain Sn(IV). In a way that is analogous to that used with the phosphorus oxyanions, the stannates are known as the orthostannate and metastannate ions. [Pg.468]

Phosphorus oxyanions are entirely different from nitrogen oxyanions. First, the oxyanion species present is controlled by the pH also, phosphate oxyanions are generally not mobile in soil. However, sandy soils and soils high in phosphorus are exceptions to this rule. Any soil, though, can lose phosphate by erosion and this phosphate can cause environmental problems. Because of its unique chemistry, phosphorus will be discussed separately later. [Pg.142]

Another oxyanion of interest to soil chemists is that of tungsten, which is in itself important but is also important because it forms polymers and reacts with both molybdenum and phosphorus oxyanions to form mixed polymers. Because tungsten species are toxic, its oxyanionic species, including polymers, are of interest [28],... [Pg.142]

Bednar AJ, Mirecki JE, Inouye LS, Winfield LE, Larson SL, Ringelberg DB. The determination of tungsten, molybdenum, and phosphorus oxyanions by high performance liquid chromatography inductively coupled plasma mass spectrometry. Talanta 2007 72 1828-1832. [Pg.150]

Phosphorus and arsenic are both group 15 elements. The main phosphorus oxyanion, phosphate (PO43- ), has the same charge and tetrahedral configuration as inorganic As(V), which allow phosphate to out compete As(V) for adsorption sites on clay minerals and various iron and aluminum compounds over a wide range of pH conditions (Stollenwerk, 2003), 85 (Gao and Mucci, 2001) (Su and Puls, 2003), 2582. Phosphate is also capable of desorbing arsenic from humic acids and some mineral surfaces (Stollenwerk, 2003), 91 (Mok and Wai, 1994), 111 (Lafferty and Loeppert, 2005), 2120. [Pg.56]

Dietz, E. R. (1983). Scattered-wave calculations of the phosphorus L X-ray emission spectrum of ligand-substituted phosphorus oxyanions. J. Phys. B16, 4593-9. [Pg.470]

These mutants provided a unique opportunity for us to examine whether phosphonate transition state similarity extends beyond simple geometric considerations. We posed the question how will mutation at position 127 affect inhibitor binding A correlation between log(Kj) and log(Km/kcat) across a series of proteins would show whether the phosphorus oxyanion, the part of the inhibitor that interacts with the 127-side chain, and the carbonyl oxygen in the transition state respond similarly to... [Pg.140]

Many important soil components are not present as simple cations or anions but as oxyanions that include both important metals and nonmetals. The most common and important metal oxyanion is molybdate (Mo042 ). The most common and important nonmetal oxyanions are those of carbon (e.g., bicarbonate [HC03 ] and carbonate [C032-]), nitrogen (e.g., nitrate [N03 ] and nitrite [NQ2 ]), and phosphorus (e.g., monobasic phosphate [H2P04 ], dibasic... [Pg.140]

Of the nonmetal oxyanions, those of carbon have a different role in soil than nitrogen and phosphorus. Bicarbonate and carbonate can act as counterions to cations to keep the soil electrically neutral. They are also important because all pH changes in soil tend to involve either carbonate or bicarbonate, and thus, both are involved in soil pH and buffering. [Pg.141]

By proton inventory, a technique that determines whether acid and base groups act simultaneously, we found that hydrolysis of 36 by artificial enzyme 44 involves two protons moving in the transition state [130]. Thus, ImH+ of 46 is hydrogen bonded to a phosphate oxyanion of bound substrate 36 water hydrogen bonded to the Im then attacks the phosphorus, and as the O-P bond forms the ImH+ proton transfers (along with the water proton) to produce the phosphorane monoanion 47. This then goes on to the cleaved product in later catalyzed steps before there is time for pseudo-rotation. These general conclusions have been described and summarized in several publications [131-137]. [Pg.13]

The phosphorus reagent is first attacked by the OH group (an 5 2 reaction at phosphorus) and the displacement of an oxyanion bonded to phosphorus is now a good reaction because of the anion stabilization by phosphorus. 0 iGy... [Pg.431]

The oxyanions of phosphorus and arsenic take up the major portion of a recent large volume of Gmelin (C9), which includes more than 100 compounds, hydrates and phases containing phosphate groups.263 To pursue the detail of the latter is an exercise in phosphorus chemistry, so we concentrate on a survey of the available data on the Mn" coordination polyhedra. [Pg.45]

Phosphates are compoimds that contain oxyanions of phosphorus(V), ranging from the simple orthophosphate group to condensed chain, ring, and network anions. Oxyanions of phosphorus in lower oxidation states such as phosphite, HP03, are also known. [Pg.3628]

The orthophosphate group, P04 , (often shortened to phosphate ) is the most ubiquitous oxyanion of phosphorus. In solid orthophosphates, all four oxygen atoms are usually coordinated to cations resulting in a strongly bonded three-dimensional framework, although layered or chain structures sometimes result. [Pg.3628]

The oxyanion of nitrogen in which it has the highest oxidation state is the nitrate ion (N03 ). The corresponding oxyanion of phosphorus is P043-. The N043 ion is known but is not very stable. The P03 ion is not known. Account for these differences in terms of the bonding in the four anions. [Pg.924]

Following a short review of early studies of the valence band of tetrahedral oxyanions of types X04" some recent results of this field are discussed. High resolution XPS measurements of the valence band of phosphorus and sulphur oxyanions made possible a rigorous test of various theoretical models. For DV-Xa cluster MO calculations, experimentally determined crystal structure information were used to set up realistic model clusters. In the case of the S04 cluster, the results of several model calculations ab initio, DV-Xa, hybrid models) are presented. From the comparison of these results a better understanding of the role of the contributions from different effects to the MO one-electron energies can be obtained. [Pg.207]


See other pages where Phosphorus oxyanions is mentioned: [Pg.141]    [Pg.214]    [Pg.217]    [Pg.89]    [Pg.65]    [Pg.142]    [Pg.141]    [Pg.214]    [Pg.217]    [Pg.89]    [Pg.65]    [Pg.142]    [Pg.115]    [Pg.160]    [Pg.161]    [Pg.220]    [Pg.250]    [Pg.265]    [Pg.663]    [Pg.144]    [Pg.227]    [Pg.297]    [Pg.224]    [Pg.341]    [Pg.355]    [Pg.152]    [Pg.10]    [Pg.297]    [Pg.543]    [Pg.428]    [Pg.429]    [Pg.750]    [Pg.847]   


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