An anomalous X-ray diffraction study of yttrium(III) hydration

Anomalous X-ray Diffraction (AXD) methods were used to determine the hydrat ion structure of Y2+ in a 3.5 rn solution of yttrium chloride in water. Dat a were gathered at two wavelengths below the absorption edge of Y3+. The da ta were corrected for attenuation, inelastic scattering and background and container scattering. They were then renormalized and put on an absolute sc ale of electron units. Fourier transformation of the results provided infor mation on the Y3+ hydration. It is found that the short range order around Y3+ is well established with two well-defined hydration shells. The first, with Y3+. . .H2O centered at around 2.30 Angstrom contains 8 water molecule s, and the second with Y3+. . .O and Y3+. . . Cl- is centered at 4.77 Angst rom. The results are in excellent agreement with a recent EXAFS+XANES study . Moreover, it can be shown that the contributions to the first hydration s hell from O and H can be resolved in to two peaks, with maxima at 2.28 and 2.95 Angstrom respectively. However, it is not possible to accurately deter mine coordination numbers for these Y3+. . .O and Y3+. . .H correlations in dependently due to the approximate nature of the calculations.