[antimatter101]

Chlorine has a motley of oxidation states, the positive ones being +1, +3, +5 etc, as shown in chlorate ClO₃^-, perchlorate ClO₄^- etc. What is the structure of bonding in these molecules?

[camptzak]

hey man,
im pretty sure that ClO₃, ClO₄ have tetrahedral geometry
I could be wrong, google it.

[antimatter101]

So chlorine in ClO₃^- has one lone pair, while chlorine in ClO₄^- has none, so chlorine in ClO₄^-has a charge of +3, right?

[Borek]

so chlorine in ClO₄^-has a charge of +3, right?

Wrong.

This is a basic and trivial calculation of the oxidation number.

[antimatter101]

Please explain what the bonding is like in these molecules, then.
Is it a bit like the ones in phosphoric-sulphuric acid then?
Is it hypervalence?
Does chlorine have any formal charges?

[JPA]

lets try the ClO₃,
first you have to find how many valence electrons in the molecule.
7 valence electrons for the chlorine atom and 18 valence electrons for the Oxygen atom. add 1 for the - charge. 7e + 18e + 1e = 26electrons. 
then substract 6e for the three single bonds between Cl nd O. 26e - 6e = 20electrons.
then contribute each electrons to the molecule according to the octect rule. then you can get the structure of molecule with two double bonds and one single bond and one lone pair.
the geometry of the electron pairs is tetrahedral. but the geometry of molecule is trigonal piramidal.
there is no formal charge for the  Cl atom.
http://chemwiki.ucdavis.edu/Theoretical_Chemistry/Chemical_Bonding/Lewis_Theory_of_Bonding/Lewis_Structures ( use this for further) it will help you

[antimatter101]

Chlorine usually needs one electron and is satisfied. Like phosphorous and sulfur.

[Big-Daddy]

Chlorine usually needs one electron and is satisfied. Like phosphorous and sulfur.

Cl is dealing with oxygen, it may well end up unsatisfied. Think instead in terms of how many valence electrons Cl has and how it can use them.

Simply think about it like this: for every O you want to end up neutral (talking formal charges), give it a double bond with the Cl, and for the O you want to end up with the -1 formal charge give it a single bond. So for ClO-, Cl has 3 lone pairs and a single bond to O; for ClO₂-, Cl has 2 lone pairs, a double bond to an O and a single bond to an O (bent,v-shaped geometry, right?); ClO₃^- has 1 lone pair, 2 double bonds to O and a single bond to another O, so it will have pyramidal geometry. What about ClO₄^-?