You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
hexasodium;3-[[2,2-diphosphonatoethyl(oxido)phosphoryl]methyl]-4-hydroxy-4-oxobutane-1-sulfonate is the IUPAC name of a molecule. Please give its molecular formula.
user
C7H11Na6O13P3S
assistant