  The ternary stannide CeRuSn is a static mixed-valent cerium compound with an
or-dering of trivalent and intermediate-valent cerium on two distinct
crystallographic sites. 119Sn M\"ossbauer spectra showed two electronically
almost identical tin atoms at 323 K, while at 298 K and below (77 and 4.2 K)
two tin sites can clearly be distinguished. 119Sn solid state NMR experiments
are performed to probe the local hyperfine fields at the two different Sn
sites. 119Sn NMR powder spectra are nicely fitted with two Sn sites with nearly
the same magnetic anisotropy, but with different absolute shift values. Both Sn
sites are strongly affected by crossover-like transitions between 100 and 280
K. This local-site study confirms the superstructure modulations found in
previous investiga-tions. Towards lower temperatures the powder spectra are
broadened giving strong evidence for the antiferromagnetically ordered ground
state.
