Phosphorus oxides/oxoacids

Discuss key features of Group 5A(15), especially patterns in oxidation state, oxide acidity, and hydride and halide structures and describe the nitrogen and phosphorus oxides and oxoacids ( 14.6) (EPs 14.48-14.58)... 

Oxides can be defined as binary compounds formed between various elements and oxygen, while phosphates can be defined as salts based formally on phosphorus (V) oxoacids and in particular salts of phosphoric (V) acid, H3PO4. Both oxides and phosphates are among the most important classes of inorganic compounds. For example, silicon dioxide (Si02) is the main compound in the Earth s crust, and apatite, a complex mineral form of calcium phosphate, Ca5(P04)3 (OH, F, Cl) is the main compound on the enamel of teeth [1-3],... 

Historically, where the central element forms oxoacids in two oxidation numbers, the higher state is indicated by the suffix -ic (as in phosphoric acid, H3PO4, phosphorus oxidation number +5), and the lower state by the suffix -ous (as in phosphorous acid, H3PO3, phosphorus oxidation number +3.)... 

Figure 12.16 Oxidation state diagram for phosphorus. (Note that all the oxoacids have a phosphorus covalency of 5.)...

Table 12.9 Some lower oxoacids of phosphorus (Supcrscripl numerals in the abbreviated notation indicate oxidation stales)...

Oxides and Oxoacids of Phosphorus When phosphorus burns in air or oxygen, it yields tetraphosphorus hexoxide (P4Og, mp 24°C) or tetraphosphorus decoxide (P4Oio, mp 420°C), depending on the amount of oxygen present ... 

The prefixes and suffixes used in Chapter 6 can also be interpreted in terms of oxidation numbers, rather than numbers of oxygen atoms. For example, the ending -ous corresponds to the oxoacid in which the central atom has the lower oxidation state in each case, and the ending -ic corresponds to the higher oxidation state. For example phosphorous acid has phosphorus in the +3 oxidation state phosphoric acid has phosphorus in the + 5 oxidation state. Phosphorus in hypophosphorous acid has an oxidation number +1. 

Both phosphorus trichloride and phosphorus pentachloride react with water in a hydrolysis reaction, a reaction with water in which new element-oxygen bonds are formed and there is no change in oxidation state. An oxoacid and hydrogen chloride gas are formed in the reaction. 

Nitrogen Oxides 24-16 Some Oxoacids of Nitrogen and Their Salts Phosphorus... 

It is also well known (2) that not all oxoacids of phosphorus react with molybdenum ion to form a positive blue complex at the same rate. Time studies were done on plasma PSG wafers. Figure 1 shows distinct differences between the phosphate ion and doped oxide film from a wafer when analyzed with and without oxidation. 

White phosphorus, P4, is highly toxic, very reactive, and flammable the polymeric red phosphorus, (P4), is more stable. Phosphorus forms oxides and hahdes with oxidation numbers of +3 and +5 and several oxoacids. The phosphates are the most important phosphorus compounds. 

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