Actually, it is so; there is a detailed explanation in Life and Energy by Issac Asimov PHD ISBN:0-380-00942-0 Avon Books.
A brief explanation from Yahoo answers states:
What exactly converts CO2 to O2 in plants during photosynthesis?
by ecolink Member since:
December 26, 2006
Total points:
59526 (Level 7)
Best Answer - Chosen by Asker
“CO2 isn’t converted to O2, but photosynthesis does take in carbon dioxide to use as a raw material and it does give off oxygen gas as a waste product. The oxygen given off does not come from carbon dioxide. The oxygen comes from splitting water molecules. Photosynthesis keeps the hydrogen ions and the hydrogens’ electrons. The oxygen diffuses out.”
The water is cracked in the process, but it is also recombined, with the net result that one water molecule remains, and the other is combined with the carbon atom from the CO2 molecule, to become part of a carbohydrate.
Thus, one water molecule remains a water molecule, the other becomes part of a carbohydrate, the CO2 molecule is cracked so that the carbon becomes part of the carbohydrate and the O2 is released as gas.
What you are talking about are intermediate steps. Photosynthesis won't work without these intermediate steps, but to the world outside the plant, the net effect is that CO2 is split, the carbon retained, and the O2 released.