XAFS investigations of tin nitrides

Tin nitrides (Sn3N4) prepared by the reaction of Sn-halides with KNH2 in li quid ammonia and a subsequent vacuum annealing procedure were investigated with transmission mode XAFS experiments. While the near edge data suggest t he presence of a univalent Sn-compound with a valency close to +4, the anal ysis of the extended X-ray absorption fine structure proves the presence of two different local Sn sites in this crystal structure: While Sn(1) is sur rounded by 4 nitrogen in a distance of 2.06 Angstrom, each Sn(2) ion is coo rdinated with 6 nitrogen at about 2.17 Angstrom radial distance.