The chemical reaction pathway for the transformation of Ca3(PO4)2 into Ca3(PO4)2 is as follows:

Ca3(PO4)2 undergoes decomposition to form elemental phosphorus (P) and calcium phosphate:

Ca3(PO4)2 → Р + Ca(PO4)2

The elemental phosphorus further reacts with oxygen to form P2O5:

2P + 5O2 → 2P2O5

The P2O5 then reacts with water to form calcium dihydrogen phosphate (Ca(H2PO4)2):

P2O5 + 3H2O → 2H3PO4

Ca(OH)2 + 2H3PO4 → 2Ca(H2PO4)2 + 2H2O

Finally, the Ca(H2PO4)2 reacts with calcium hydroxide to regenerate Ca3(PO4)2:

2Ca(H2PO4)2 + Ca(OH)2 → Ca3(PO4)2 + 4H2O

Therefore, the overall transformation of Ca3(PO4)2 into Ca3(PO4)2 occurs through a series of chemical reactions involving elemental phosphorus, oxygen, water, calcium hydroxide, and calcium dihydrogen phosphate.