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Phosphorus strain energy

High level ab initio calculations have been applied to estimate the ring strain energies of three-membered heterocycles, amongst other phosphorus three-membered heterocycles are included <2006JA4598>. [Pg.478]

The barriers to permutational isomerizations in five-membered spiro-phosphoranes have been rationalized in terms of BPR processes involving diequatorial five-membered rings and preferred lone-pair orientations. The energy difference between (22) and (23) is composed of a general strain term due to the increased bond angle at phosphorus, the energy required to rotate the lone pairs on both X and Y from the preferred equatorial orientation to an... [Pg.31]

Factor (b) Phosphorus-carbon bonds are longer than nitrogen-carbon bonds (P-C 1.89 A N-C 1.47 A), and thus the ring strain energy in 38 is smaller than in 40. [Pg.193]

Solution. We see that the strain energy in red phosphorus per P4 is 4(43 — 18) = 100 kJ mole . The strain energy is about 58% of the value for the tetrahedral P4 molecule in white phosphorus. This molecule has twelve 60° bond angles. If one bond is broken, the P groups can form chains ... [Pg.201]

The composition of white phosphorus is P4. Each of the phosphorus atoms lies at the comer of a regular tetrahedron, just as the four atoms of hydrogen in methane do. The phosphoms atoms feel strain reacting to form more stable stmctures relieves that strain and releases energy. People behave in basically the same way finding ways to relieve strain. [Pg.94]

I8.lt> The P4 molecule in white phosphorus has extremely strained bonds The bond angles in the Tj molecule are only 60°. Therefore the bonds are weak, only 201 kJ mol-1 for each one. The total bond energy of two moles of Pj (962 kJ. Appendix E)is244 kJ less than that of one mole of Pi (1206 kJ. Appendix E). In contrast, the total bond energy of two moles of N. has been calculated57 to be 77 kJ greater than that of one mole of N, ta hypothetical tetrahedral molecule iscslraclund with P4)... [Pg.978]


See other pages where Phosphorus strain energy is mentioned: [Pg.733]    [Pg.121]    [Pg.303]    [Pg.390]    [Pg.17]    [Pg.733]    [Pg.40]    [Pg.877]    [Pg.38]    [Pg.258]    [Pg.128]    [Pg.733]    [Pg.15]    [Pg.278]    [Pg.2238]    [Pg.733]    [Pg.370]    [Pg.102]    [Pg.163]    [Pg.163]    [Pg.163]    [Pg.164]    [Pg.237]    [Pg.233]    [Pg.117]    [Pg.118]    [Pg.14]    [Pg.168]    [Pg.70]    [Pg.53]    [Pg.421]    [Pg.102]    [Pg.75]    [Pg.533]    [Pg.78]    [Pg.296]    [Pg.89]    [Pg.8]    [Pg.60]    [Pg.446]    [Pg.110]    [Pg.29]    [Pg.252]    [Pg.152]   
See also in sourсe #XX -- [ Pg.4 , Pg.211 ]




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