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Phosphorus pentoxide is a chemical compound with molecular formula P 4 O 10 (with its common name derived from its empirical formula, P 2 O 5). This white crystalline solid is the anhydride of phosphoric acid. It is a powerful desiccant and dehydrating agent.
White phosphorus, yellow phosphorus, or simply tetraphosphorus (P 4) is an allotrope of phosphorus.It is a translucent waxy solid that quickly yellows in light (due to its photochemical conversion into red phosphorus), [2] and impure white phosphorus is for this reason called yellow phosphorus.
It would appear that violet phosphorus is a polymer of high relative molecular mass, which on heating breaks down into P 2 molecules. On cooling, these would normally dimerize to give P 4 molecules (i.e. white phosphorus) but, in a vacuum , they link up again to form the polymeric violet allotrope.
Since the ends are condensed, its formula has one less H 2 O (water) than tripolyphosphoric acid. The general formula of a phosphoric acid is H n−2x+2 P n O 3n−x+1, where n is the number of phosphorus atoms and x is the number of fundamental cycles in the molecule's structure; that is, the minimum number of bonds that would have to be ...
Phosphorus trioxide is the chemical compound with the molecular formula P 4 O 6. Although the molecular formula suggests the name tetraphosphorus hexoxide, the name phosphorus trioxide preceded the knowledge of the compound's molecular structure, and its usage continues today. This colorless solid is structurally related to adamantane.
Phosphate is the conjugate base of phosphoric acid, which is produced on a massive scale for use in fertilisers. Being triprotic, phosphoric acid converts stepwise to three conjugate bases: H 3 PO 4 + H 2 O ⇌ H 3 O + + H 2 PO 4 − K a1 = 7.25×10 −3 H 2 PO 4 − + H 2 O ⇌ H 3 O + + HPO 4 2− K a2 = 6.31×10 −8
To put this in perspective: the lowest excitation vibrational energy in water is the bending mode (about 1600 cm −1). Thus, at room temperature less than 0.07 percent of all the molecules of a given amount of water will vibrate faster than at absolute zero. As stated above, rotation hardly influences the molecular geometry.
Most of the four-site water models use an OH distance and HOH angle which match those of the free water molecule. One exception is the OPC model, in which no geometry constraints are imposed other than the fundamental C 2v molecular symmetry of the water molecule. Instead, the point charges and their positions are optimized to best describe the ...