The solubilities of potassium dichromate in mixtures of light and heavy water with various D₂O-contents hsve been measured at 25±0.030.The solubility is expressed in two different ways:(1) Sn,the number of moles of K₂Cr₂O₇ dissolving in 55.51 moles of H₂O-D₂O mixture with the mole fraction of D₂O equalton;(2) Sx,the number of grams of K₂Cr₂O₇ dissolving in 1 gram of H₂O-D₂O mixture with the weight fraction of D20 equal to x(see Table 1, pp.321-322).