Oxides And Oxy-acids Of Chlorine : Constitution Of The Oxy-compounds Of Chlorine

If we assumed chlorine to be univalent in all its oxygen compounds, except ClO₂, these would have the following formulae:

chlorine monoxide, Cl-O-Cl hypochlorous acid, H-O-Cl.

chlorine dioxide, clorine dioxide

chlorous acid, H-O-O-Cl

chloric acid, H-O-O-O-Cl perchloric acid, H-O-O-O-O-Cl chlorine heptoxide, Cl-O-O-O-O-O-O-O-Cl.

Usually, however, the stability of compounds containing chains of singly-linked oxygen atoms decreases as the number of oxygen atoms in the chain increases. Hydrogen peroxide, H-O-O-H, is less stable than water H-O-H. We should therefore expect the stability to decrease in the series: HClO, HClO₃, HClO₄, whereas actually it increases.

Although the energy-content of the molecule is the main factor affecting stability, it is assumed that this is conditioned by the mode of linkage of the atoms, i.e., by valency. The formulae of the above compounds are usually written with the chlorine atom with different valencies, from 1 to 7 (Blomstrand, 1869).

I. Cl-O-Cl; H-O-Cl.

III and V. H-O-Cl=O;

, or

.

II and IV.

, or

.

VII.

;

, or

.

The hydrate HClO₄,H₂O may be written: hclO<sub>4</sub>,H<sub>2</sub>o

The variable valency of iodine, an element very similar to chlorine and univalent in its stable compounds, appears in the compounds ICl₃, IF₅, and IF₇.

Protein crystallography
Chemistry guide
Oxides And Oxy-acids Of Chlorine
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