Phosphate ion template

PO₄³⁻: the textbook forms with one P=O and three P–O⁻ (four equivalent ones, two shown), and the octet form with P⁺ and four P–O⁻.

What the template shows

• Four equivalent forms with one P=O, and the octet form with P⁺
• expanded octet
• Resonance contributors
• Expanded-octet forms
• Textbook convention: one P=O, three P–O⁻ (2 of 4 forms)
• Octet form
• P⁺ with four P–O⁻
• Convention: phosphate is usually drawn with one P=O (ten electrons on P); the four such forms are equivalent.
• The octet form (P⁺, four P–O⁻) is favoured by modern bonding analysis; P=O is best seen as a polar P⁺–O⁻ bond.
• All four P–O bonds are equal in the tetrahedral ion, each oxygen carrying −¾; total charge −3 in every form.
• The same delocalisation stabilises the phosphate groups of ATP, DNA and phospholipids.
• Contributors are not in equilibrium: the real species is one hybrid of them · every part of this figure is editable

Drawn with 20 atoms, 5 arrows, 3 shapes – every one editable in MolDraw.

Sources

• Housecroft & Sharpe, Inorganic Chemistry, 5th ed., Pearson 2018 Textbook