TOPOTACTIC INTERCALATION OF WATER AND PYRIDINE INTO CO(H2PO2)2NH2O ESS-THAN-OR-EQUAL-TO-N-LESS-THAN-OR-EQUAL-TO-0.69) - CRYSTAL-STRUCTURE OF CO(H2PO2)20.53H2O SOLVED FROM X-RAY-POWDER DIFFRACTION DATA
Md. Marcos et al., TOPOTACTIC INTERCALATION OF WATER AND PYRIDINE INTO CO(H2PO2)2NH2O ESS-THAN-OR-EQUAL-TO-N-LESS-THAN-OR-EQUAL-TO-0.69) - CRYSTAL-STRUCTURE OF CO(H2PO2)20.53H2O SOLVED FROM X-RAY-POWDER DIFFRACTION DATA, Inorganic chemistry, 33(6), 1994, pp. 1220-1226
The synthesis of differently hydrated layered cobalt hypophosphites, C
o(H2PO2)2.nH2O (0 less-than-or-equal-to n less-than-or-equal-to 0.69),
has been possible by carefully controlling the water content in the r
eaction medium. The crystal structure of Co(H2-PO2)2.0.53H2O has been
refined from X-ray powder diffraction data by the Rietveld method, usi
ng as a starting model the structural parameters of the orthorhombic a
nhydrous zinc hypophosphite Zn(H2PO2)2. The cell is monoclinic (space
group P112/a; Z = 2) with a = 6.4722(3) angstrom, b = 5.3411(3) angstr
om, c = 7.4900(3) angstrom and gamma = 90.087(12)-degrees. The final r
eliability factors were, R(I) = 5.38%, R(p) = 7.31%, and R(wp) = 9.05%
. The lamellar structure can be thought of as constructed from corruga
ted rutile like chains of cationic edge-sharing octahedra running alon
g the a axis and interconnected in the b direction through hypophosphi
te bridges. Co(H2PO2)2.nH2O compounds are suitable hosts lattices for
intercalation reactions. Water and pyridine intercalation processes in
these matrices have been studied by thermal analysis, variable-temper
ature X-ray powder diffraction, and spectroscopic techniques. A struct
ural proposal for Co(H2PO2)2.1.86(C5H5N).0.31H2O is presented.