BaI2·7H2O is the chemical formula for barium iodide heptahydrate. In this compound, "7H2O" indicates that there are seven water molecules of crystallization associated with each formula unit of BaI2.

To calculate the percentage of water of crystallization in BaI2·7H2O, we need to determine the molar mass of the water molecules and the total molar mass of the compound.

Molar Mass of Ba = 137 and I = 127 and H2O = 18

Total molar mass of the compound = Ba molar mass + 2 x ( molar mass of I) + 7 x (molar mass of H2O)

= 137 + 2 x 127 + 7 x 18 = 517

To find the percentage of water of crystallization, we divide the molar mass of the water molecules by the total molar mass of the compound and multiply by 100:

= (126 / 517) x 100 = **24.37%**