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Phosphorus pentoxide crystallizes in at least four forms or polymorphs.The most familiar one, a metastable form [1] (shown in the figure), comprises molecules of P 4 O 10.Weak van der Waals forces hold these molecules together in a hexagonal lattice (However, in spite of the high symmetry of the molecules, the crystal packing is not a close packing [2]).
Diphosphorus is the gaseous form of phosphorus, and the thermodynamically stable form between 1200 °C and 2000 °C. The dissociation of tetraphosphorus (P 4) begins at lower temperature: the percentage of P 2 at 800 °C is ≈ 1%. At temperatures above about 2000 °C, the diphosphorus molecule begins to dissociate into atomic phosphorus.
The odour of combustion of this form has a characteristic garlic odor, and samples are commonly coated with white "diphosphorus pentoxide", which consists of P 4 O 10 tetrahedra with oxygen inserted between the phosphorus atoms and at their vertices. White phosphorus is only slightly soluble in water and can be stored under water.
Phosphorus pentoxide (phosphorus(V) oxide, phosphoric anhydride), P 2 O 5; Phosphorus trioxide (phosphorus(III) oxide, phosphorous anhydride), P 2 O 3; Phosphorus tetroxide, P 2 O 4; Several other, less common, oxides of phosphorus, including P 4 O 7, P 4 O 9, and P 2 O 6; Gases: Phosphorus monoxide, PO; Phosphorus dioxide, PO 2
Diphosphorus is an inorganic chemical with the chemical formula P 2 . Unlike nitrogen, its lighter pnictogen neighbor which forms a stable N 2 molecule with a nitrogen to nitrogen triple bond , phosphorus prefers a tetrahedral form P 4 because P-P pi-bonds are high in energy.
Phosphorus pentoxide (P 4 O 10) is the acid anhydride of phosphoric acid, but several intermediates between the two are known. This waxy white solid reacts vigorously with water. With metal cations, phosphate forms a variety of salts. These solids are polymeric, featuring P-O-M linkages.
Diphosphorus tetroxide, or phosphorus tetroxide is an inorganic compound of phosphorus and oxygen. It has the empirical chemical formula P 2 O 4 . Solid phosphorus tetroxide (also referred to as phosphorus(III,V)-oxide) consists of variable mixtures of the mixed-valence oxides P 4 O 7 , P 4 O 8 and P 4 O 9 .
M5 fiber is prepared by a condensation polymerization between tetraaminopyridine and dihydroxyterephthalic acid using diphosphorus pentoxide as a dehydrating agent. The polymer mixture is then heated and extruded to form brightly blue polymer fibers.