Heptavalent chlorine

The Stoichiometry of the reaction further indicates that one OH must be adding to ClOj. A potential stumbling block in writing this out, however, is that the Lewis stmcture used for chlorine dioxide until now is not particularly representative of its real electronic stmcture. It s better to view CIO2 as a resonance hybrid  

The product C103 , a one-electron-reduced chlorate anion, could then reduce ClOj to CIO2-  

This remarkable dehydrating action of P4O10 reflects both the ability of the 0x0 groups to act as proton acceptors and the oxophilicity of the pentavalent phosphoms centers. Protonation 

Additional protonation of a nearby oxygen of the P4O10 skeleton is expected to prime the coordinated perchlorate to nucleophilic attack by a second perchlorate, resulting in CI2O7. 

The unusual oxide CI2O6 may be prepared via the interaction of CIO2F and HCIO4. Suggest a structure for CI2O6 and a mechanism underlying the preparative route. 

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In OUT final example in this section, we will consider the synthesis ofperchloryl fluoride, FCIO3, another heptavalent chlorine compound ... 

The heptoxide can then be distilled off under reduced pressure at 35 °C. It is an oily liquid (Tb 81 °C) liable to explode on mechanical shock. The different Cl—O bond lengths in the molecule support the structural formula of Figure 6.17, which contains heptavalent chlorine. 

Structure (3.226c), for example, depicts a central heptavalent Cl atom (Fa = 7), exceeding the normal valence octet by six electrons (These excess electrons are assumed to be accommodated in chlorine 3d orbitals, whereas d-orbital participation is prevented in first-row compounds.) Hypervalent structures such as (3.226a)-(3.226c) are claimed to be justified by the electroneutrality principle, which stipulates that second-row central atoms have zero formal charge (whereas first-row oxyanion Lewis structures commonly violate this principle).148... 

Some elements, like hydrogen, oxygen, or the alkali metals, seem always to have the same valency in all of their compounds. Other elements however show different valencies thus, for example, chlorine can be mono-, tri-, penta- or heptavalent in its compounds. It is true that compounds of the same element with different valencies show different physical and chemical characteristics. 

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