When a coordination compound CrCl3 · 6H2O is mixed with AgNO3, two moles of AgCl are precipitated per mole of the compound. What is the structural formula of the coordination compound?
a) [Cr(H2O)6]Cl3
b) [Cr(H2O)3Cl3] · 3H2O
c) [Cr(H2O)4Cl2]Cl · 2H2O
d) [Cr(H2O)2Cl4] · 4H2O