Phosphorus solid state

What had to be omitted from this volume The large and important area of phosphorus solid-state chemistry has been omitted, not because it is not important, but because it could constitute a volume in itself. For that same reason, the related area of volatile phosphorus precursors for solid-state synthesis has received only passing attention (see Chapter 4). Military applications of phosphorus were deliberately passed up for more positively focused topics. 

Marina OA, Coyle CA, Thomsen EC, Edwards DJ, Coffey GW, Pederson LR (2010) Degradation mechanisms of SOFC anodes in coal gas containing phosphorus. Solid State Ionics 181 430-440... 

However, phosphorus pentachloride in the solid state has an ionic lattice built up of (PC ) and (PClg)" ions and these ions are believed to exist in certain solvents. Thus under these conditions the maximum covalency is reached with chlorine. In phosphorus pentabromide, PBrj, the solid has the structure [PBr4] [Br] . 

Hyperpure silicon can be doped with boron, gallium, phosphorus, or arsenic to produce silicon for use in transistors, solar cells, rectifiers, and other solid-state devices which are used extensively in the electronics and space-age industries. 

The element phosphorus forms a variety of allotropic forms in the solid state. In the chemistry stockroom, you are likely to find red phosphorus and possibly white phosphorus (Figure B). As you can see, white phosphorus has the molecular formula P4, whereas red phosphorus might be represented as Px, where x is a very large number. The difference in properties between the two allotropes reflects the difference in their bonding patterns, molecular versus network covalent ... 

The JV-phosphino-l-azadiene 66 undergoes cycloaddition with DMAD in ether at -20 °C to form the bridged structure 67 <96AG(E)896>. The new compound is thermally unstable and isomerises to the alternative bridged structure 68 at 25 °C. X-ray analysis data have been interpreted to suggest that the isomer 69 co-exists in the solid state. The same ring system is also formed by protonation at the sp carbon atom neighbouring phosphorus in 67 (Scheme 15). 

The stability of phosphinous amides depends, to a large extent, on the substituents at phosphorus and nitrogen. Normally, tetrasubstituted and N,P,P-trisubstituted phosphinous amides are stable and well-known compounds. The parent compound H2PNH2 is a volatile compound that is formed on hydrolysis of a solid state solution mixture of magnesium phosphide and magnesium... 

Boron trifluoride, sulphur and disulphur dichlorides, phosphorus trichloride in the liquid state cause potassium to combust. The same is true for phosphorus pentachloride in the solid state. In the latter case the same accident happened with gaseous halide. The same is also true for the bromide analogues of these compounds. 

Many catalysts, both immobilized (on solid state supports) and heterogeneous, contain phosphines and other phosphorus compounds, so that solid state NMR has become an invaluable tool in the study of catalysis. 

Measurements made on a group of 3 structurally similar organophospho-rus compounds containing one, two and three phosphorus nuclei shows the power of solid state NMR. The relevant data are given in Table 6, while Fig. 51 shows the three MAS spectra. 

Noteworthy NMR studies involving nuclei other than phosphorus have been carried out for some P-chloro-NHPs where the possible occurrence of spontaneous P-Cl bond dissociation was probed by II NMR titrations and 35C1 NMR [20], and for P-cyclopentadienyl derivatives where measurement of solid-state 13C CP-MAS NMR spectra allowed one to substantiate the preservation of the circumambulatory ring migration of cyclopentadienyl groups in the solid state [47], Several neutral and cationic derivatives have also been studied by 15N NMR [20, 53],... 

Solid-state NMR spectroscopy was used for studying the formation of cubic mesoporous aluminophosphate thin films and powders. The analysis of the initial gel, the as-deposited materials and the thermally-treated materials elucidated the changes in the coordination of phosphorus and aluminium atoms and thus revealed how the framework formation and condensation proceeds. The consolidation process in thin films was different than the process in powders. Most probably this could be attributed to the effect of glass substrate. 

Studies on the solid-state structures, vibrational frequencies and dipole moments of tertiary phosphine chalcogenides have shown the phosphorus to be in an approximately tetrahedral environment with phosphorus-chalcogen bond lengths in-between those expected for single and double bonds.21 There has been much debate on the nature of the phosphorus-chalcogen bond in these... 

The monochalcogenides 43 can also theoretically exist in more than one tautomeric form an N-H tautomer 43a, a P-H tautomer 43b or an E-H tautomer 43c. Solution and solid-state studies on these compounds show that, depending upon the nature of the R substituents, either the N-H or the P-H tautomer predominates. Substituents which lead to increased basicity of the phosphorus lone-pair (e.g., R = NMe279, Pr80) have been shown to favour the formation of the P H tautomer, whereas in systems where the phosphorus lone pair is less basic (e.g., R = Ph81) the N-H tautomers are favoured. 

Coordination of [(t-C4H9)2P(=Se)I] with molecular iodine furnishes a 1 1 adduct that crystallises as cyclic dimer in the solid state (Figure 46).57 From each I2 molecule within the structure, one atom acts as acceptor towards selenium, and the other one becomes very weak donor towards the iodine atom bonded to phosphorus. This compound fulfills the requirements of a soft-soft base pair . As in the structure of the parent donor molecule [(t-C4Hg)2P(=Se)I],... 

The reaction of 18 and 19 with phosphorus ylides occurs as a stepwise process. Betaine (21) can be isolated when (Me2SiS)3 reacts with Ph3P=CHMe in a 3 2 ratio of the reactants (Scheme 11). This substance is quite stable in the solid state but on dissolving in pyridine it is reversibly transformed into a mixture of 20k and (Me2SiS)3. The equilibrium concentration of 21 in a solution at room temperature is at most 28% according to the NMR data, and the addition of one more equivalent of Ph3P=CHMe to the solution results in the quantitative transformation of 21 into 20k. 

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