Measurements of the perturbed angular correlation have been made for the first ${\frac{5}{2}}^{+}$ excited state of ${\mathrm{Ta}}^{181}$ in ${\left(\mathrm{N}{\mathrm{H}}_4\right)}_3$Hf${\mathrm{F}}_7$ in order to solve a controversial question related to the structure of the complex Hf${\mathrm{F}}_7$ in this compound. The results obtained suggest a structure for Hf${\mathrm{F}}_7$ and a relaxation mechanism for the angular correlations which are consistent with each other. The relaxation constant ${\lambda }_2$ was found to be ${\lambda }_2=0.05\mathrm{}$ ${\mathrm{nsec}}^{-1\mathrm{}}$ at room temperature. A comparison of our results with the different configurations reported in x-ray literature is made.

• Received 8 September 1969

DOI:https://doi.org/10.1103/PhysRevB.1.2912