Crystal Growth of Deuterated KDP and Determination of the Deuterium Content

The relation between the deuterium concentration in the solution and in the solid phase during the growth of K(H, D)₂PO₄ crystals at 30, 45, and 60°C has been examined. The solubility of K(H, D)₂PO₄ in deuterated water was measured. The concentration of D₂O in the solvent has been determined by means of the interferometric method with an accuracy of ± 0.4 mol%. The deuterium concentration in the crystals was measured with an accuracy better than ± 1.2 mol% by the same method after decomposing them thermally. The deuterium content in crystals is determined by the deuterium content in the solvent. It is practically not influenced by temperature.