PAC measurements were performed for 111 In in LaAg 6 In 6 , PrAg 6 In 6 and NdAg 6 In 6 . It appears that the probe atom occupy three available sites in the crystal lattice with quite a similar probability. There is a small preference for In atoms to occupy a selected lattice site which is not the same in different compounds.The tetragonal ThMn 12 structure has three different Mn positions, denoted in Wyckoff notation by 8i, 8j and 8f. Such a structure is formed by a wide family of ternary compounds in which the Th positions are occupied by rare earth atoms and the Mn positions are occupied by atoms of two elements with specific compositions. For example it has been shown [1] that RAg 6 In 6 alloys (R = La, Pr, Nd) crystallize in the ThMn 12 structure only for the exact 1 : 6 : 6 stoichiometry. The PAC technique offers the possibility to study the relative occupation of the available sites for In atoms.The PAC measurements were performed for 111 In probe in LaAg 6 In 6 , PrAg 6 In 6 and NdAg 6 In 6 in a wide temperature range. R-Ag-In alloys have been prepared by melting the elements in stoichiometric quantities in an arc furnace under a protective argon atmosphere. Then the alloys were annealed at 670 K for two weeks. The 111 In radioactivity was introduced into the samples by alpha particle irradiations of each compound itself. The 111 In isotope was produced in the targets as a result of the 109 Ag(a, 2n) 111 In nuclear reaction. Before the PAC measurements the samples were annealed again at 670 K in order to remove radiation damages. Examples of the PAC spectra are shown in Figure 1.All spectra which were taken below 400 K could be fitted assuming three fractions of 111 In atoms exposed to the EFG of three different magnitudes. For

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