[padawan]

Hello everybody!
this is my first topic in this forum. I try to find a equation to calculate the minimum number of bond angle that describe to a molecule. for example I know that the minimun bond angle for a cabonate ion is 2 because the third angle is a function of the two other angles and if I consider this third angle would introduce a redundancy in the phase space of the molecule. because of that I'd wish to have an equation that tells me the number of minimum angles for a molecule.
in bond, torcional angles (or proper angles) and out of plane angles (or improper angles) the redundance problem also is present
I hope that someone help me in this issue.
thanks in advance

[AWK]

This is a quite complex problem. Even for a 4 atoms molecule (or an ion) you can get different answers, ie:
2 angles for linear species, 3 angles for flat or pyramidal species, 4 or 5 angles for cyclic species and 6 angles for bicyclic specie. For 5 atoms you  have 3 to 9 possible angles (try to draw all these structures). Moreover only angles are insufficient to show a proper configuration.