The infra-red spectra, between 4000-400 cm(-1), and the Raman spectra, between 1700-950 cm(-1), of all the complexes of urea with group II metal halides are recorded to distinguish the mode of coordination of urea in these complexes. The e.s.r. spectra, at both (X) under bar- and Q-band of Mn(II) ions doped in these complexes are reported and the zero-field splitting parameters D and lambda (=E/D) are deduced. For anhydrous complexes, with 1:4 stoichiometery, the observed D and lambda values are consistent with trans-MO(4)X(2) chromophores. Very small values of D observed for the hydrated analogues suggest an MO6(2+) chromophore. For 1:6 complex of CaCl2, the value of D and lambda is exactly similar to that of Ca(urea)(4)Cl-2, suggesting similar structure. For all other complexes of 1:6 stoichiometery, the observed values are consistent with a coordination sphere of six oxygen atoms.
I HUSSAIN ,M GOODGAME ,
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