Crystal and anion structure, TGA, DTA and infrared and Raman spectra of manganese(II) nitroprusside dihydrate, Mn[Fe(CN)5NO].2H2O

A. BENAVENTE; J. A. DE MORÁN; O. E. PIRO; E. E. CASTELLANO; P. J. AYMONINO

JOURNAL OF CHEMICAL CRYSTALLOGRAPHY

Plenum

Año: 1997 vol. 27 p. 343 - 352

1074-1542

The single crystal and anion structure of Mn[Fe(CN)sNO´2H~_O, obtained by slow interdiffusion of reactant solutions through a TMS gel, was solved by X-ray diffraction methods and refined to RI = 0.036. Spatial group: orthorhombic, Pnma, a = 14.069(2), b = 7.538(1), c = 10.543(1) A, Z = 4. The Mn(ll) ion and the water molecules are sited on mirror planes, which bisect the nitroprusside ions. One of the water molecules is coordinated to Mn(lI) and the other, strongly hydrogen (as acceptor) bonded to the first molecule. The IR spectrum confirms the bonding of the water molecules and TGA results are in accordance with the dihydrate character of the substance and its dehydration in two successive steps. DTA results and the Raman spectrum agree with other results and the comparison between IR and Raman vNO wavenumbers confirms the expected strong vibrational interaction between the closely packed antiparallel (eclipsed) NO groups. There is a topotactic relationship between the dihydrate and the trihydrate, which crystallizes in the space subgroup P21/n.