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system
Name the molecular formula for the molecule established as [[(2R,4S,5R)-5-[6-(1-azabicyclo[2.2.2]octan-3-ylamino)-2-chloropurin-9-yl]-3,4-dihydroxyoxolan-2-yl]methoxy-hydroxyphosphoryl]methylphosphonic acid using the IUPAC nomenclature.
user
C18H27ClN6O9P2
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