Lewis structure

[xenamclean_1G]

For the Lewis structure of PO4 3-, I know it has one double bond and the rest are single, but why can't all four be double bonds with all of the O having 0 formal charge and the P having a 3- charge?

[haileyramsey-1c]

The lewis structure for PO4 3- would be with P in the center and 4 oxygen surrounding, 3 of which connected with a single bond and one with a double bond. You wouldn't put 4 double bonds as you want to distribute the charge. So, having a charge of 3- is really high and not favorable. Also, oxygen is the more electronegative element so it is ideal for it to have a charge over phosphorous and if three oxygen's have -1 charge that is more evenly spread and more favorable.

[chemboi]

What is the reasoning behind only having one double bond, instead of two or three?

[LNgo 1G]

Phosphorus can only have 5 bonds total since there are only 10 electron places in the d shell that it uses to expand its octet.

[Anthony Hatashita 4H]

O is more electronegative than P so it receives the negative charge, and you want the charges to be spread out, not on one atom usually

[305376058]

The phosphorus in the center is less electronegative than oxygen so it wouldn't make sense for it to attract such a large negative charge. Additionally, it is less stable in general for any one element in the structure to have such a large charge.