Emission Mossbauer spectroscopy of Co-57 in the Na-Co-O system

A compound of cobalt in the highest oxidation state was found in the Na-Co- O system at a sodium-to-cobalt molar ratio of 10 : 1. Emission Mossbauer sp ectrum of this compound labeled with Co-57 is a doublet with the chemical s hift relative to sodium nitroprusside delta = 0.02+/-0.01 mm s(-1), the qua drupole splitting Delta E = 0.42+/-0.01 mm s(-1), and the the half-width Ga mma = 0.52+/-0.01 mm s(-1). Grinding of the samples promotes decomposition of this compound. Highly oxidized cobalt derivatives with unusual parameter s of Mossbauer spectrum were found on introduction of carrier-free Co-57 in to a sodium peroxide matrix.