The formula of tetraammineaquachloridocobalt(III) chloride is

Tetraammine (\( 4 NH_3 \)), aqua (\( H_2O \)), chlorido (\( Cl^- \)) attached to Co(III). Coordination sphere is \( [Co(NH_3)_4(H_2O)Cl]^{2+} \). To balance \( +2 \), two \( Cl^- \) ions are outside the coordination sphere, giving \( [Co(NH_3)_4(H_2O)Cl]Cl_2 \).