Parallels between S and fe(co)a -2 S Fe(co)4 Fe2(co)9, Fe3(CO)12 H2SpK1=7.24 H2Fe(Co)a pKi=4.44 pk2=14.92 pk2=14 (CO)4 F CH2-CH2 CH2=CH2Parallels between S and Fe(CO)4 S -2 Fe(CO) 4 -2 S8 Fe2(CO) 9, Fe3(CO) 12 H2 S pK1 = pK2 = 7.24 14.92 H2 Fe(CO) 4 pK1 pK2 = 4.44 =14 S CH2 (CO) 4 Fe CH2 CH2 CH2