DETERMINATION OF THE MOSSBAUER PARAMETERS OF NITROSYLPENTACYANOFERRATES (NP)

The Mossbauer parameters isomer shift (IS), quadrupole splitting (QS), and probability of recoilless absorption f' of 26 nitroprussides have been measured at room and liquid nitrogen temperatures. The values of the QS and the IS of the different compounds are close to each other, which is supposed to result from the same short-range environment of the Fe atom in the [Fe(CN)(5)NO](2-) ion. A weak correlation between I S and electronegativity of the lattice cation, as well as between QS a nd CNtrans stretching vibrations was found. For some of the investigat ed nitroprussides a Goldanskii-Karyagin effect was observed. The Mossb auer parameters IS and QS for two long-living electronic metastable co nfigurations in some nitroprusside single crystals are measured, too. Like in the case of ground state, these parameters are very close to e ach other, which shows that for the new metastable states the changes in the electron density distribution of the [Fe(CN)(5)NO](2-) anion do not practically depend on the kind of the metal cation. (C) 1996 Acad emic Press, Inc.