1. Site occupancies in the R 2-x Fe 14+2x Si 3 (R = Ce, Nd, Gd, Dy, Ho, Er, Lu, Y) compounds studied by Mössbauer spectroscopy A. Błachowski 1, K. Ruebenbauer 1, J. Przewoźnik 2, J. Żukrowski 2, D. Sitko 3, N.-T.H. Kim-Ngan 3, A.V. Andreev 4 1 Mössbauer Spectroscopy Division, Institute of Physics, Pedagogical University, Kraków, Poland 2 Solid State Physics Department, Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Kraków, Poland 3 Surface Physics Division, Institute of Physics, Pedagogical University, Kraków, Poland 4 Institute of Physics, Academy of Sciences, Prague, Czech Republic

2. R 2 Fe 17 R 2 Fe 14 Si 3 Y Ce Nd Sm Gd Tb Dy Ho Er Tm Lu

3. Crystal structure 4 + 1(?) iron crystallographic positions R 2-x Fe 14+2x Si 3

4. Iron hyperfine sites 7 + 1(?) iron magnetic positions

5. X-ray powder diffraction

6. CrystallographicMagnetic

7. R 2-x Fe 14+2x Si 3 Regular iron site occupancies Contribution (at. % Fe) Ce Nd Gd Dy Ho Er Lu Y Contribution (at. % Fe) 6c 4f 9d 6g 18f or 18h 12j or 12k 18h or 18f 12k or 12j

8. R 2-x Fe 14+2x Si 3 Non-stoichiometry parameter 2x Ce Nd Gd Dy Ho Er Lu Y

9. R 2-x Fe 14+2x Si 3 Conclusions Si atoms avoid 6c (4f) and 9d (6g) sites for R3m (P63/mmc) structure. Fe atoms partly replace R atoms on 6c-R (2b) sites for R3m (P63/mmc) structure forming 12e (4e) dumbbells. Non-stoichiometry parameter x = 0.25(5) for all compounds investigated.