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Schlagwörter:
boron; phosphorus; borophosphate; helical structures
Zusammenfassung:
A borophosphate hydrate with general composition {(NH4)(x)Co((3-x)/2)}(H2O)(2)[BP2O8].(1-x) H2O (xapproximate to0.5) was prepared under mild hydrothermal conditions (T=170degreesC). The crystal structure of the purple title compound was refined in space group P6(5) (no. 170) as a meroihedric twin (a=949.14 pm, c=1558.25 pm, R-1=0.037, wR(2)=0.092 for all data). According to preliminary X-ray investigations, vis-spectra, and magnetic susceptibility measurements, a second blue coloured variant exhibits a superstructure of the title compound with a change in coordination numbers around cobalt from six and five to six and four. Both phases show reversible de-/rehydration properties.
