Präparation, Kristallstruktur, Schwingungsspektren und thermische Analyse von Kupfer‐tetrahydrogen‐decaoxo‐diperiodat‐hexahydrat CuH₄I₂O₁₀·6H₂O

Abstract

Kupfer‐tetrahydrogendecaoxodiperiodat‐hexahydrat CuH4I2O10·6H2O wurde durch Kristallisation aus stark saurem Milieu erhalten. In der Struktur der Verbindung ((S.G. P 21/c, Nr.14), Z = 2, a = 1060, 2(2) pm, b = 551, 1(1) pm, c = 1164, 7(2) pm, β = 111, 49(3)°) liegen centrosymmetrische [H4I2O10]2— Anionen in Form kantenverknüpfter Oktaeder vor, die über Wasserstoffbrückenbindungen zwischen den sauren, trans‐ständigen OH‐Gruppen der Anionen zu Schichten verknüpft sind. Die Ramanspektren der Verbindung werden im Bereich der inneren Schwingungen des Periodat‐Anions analysiert. Die Entwässerung von CuH4I2O10·6H2O erfolgt über CuH4I2O10·3H2O zu Cu(H2IO5)2, das sich bei 170 °C zu Cu(IO3)2 zersetzt.

Vibrational analysis of the H4I2O102− ion in CuH4I2O10·6H2O

“…4 However, as we assume the factor-group splitting for the internal vibrations to be small there will be 21 Raman-active and 21 IR-active vibrations only, which will be distributed over a relatively wide wavenumber region. The (Fig.…”

“…7 The starting point for the structure investigations was the X-ray structure. 4 5 where the surrounding atoms were described by a semiempirical or force-field method.…”

“…In the literature only very few data can be found on periodates with the anion H 4 10 . The vibrational spectra of the different decaoxodiperiodate ions are not well known until now.…”

“…There are only three papers in the literature 2 -4 dealing with the IR-and Raman spectra of the diperiodate ion and the assignment of its internal vibrations. As the assignments given in the different papers are contradictory in some parts we decided to calculate the vibrational wavenumbers and the vibrational modes of the H 4 …”

“…IR spectrum of CuH4 I 2 O 10 Ð6H 2 O. single unit H 4 I 2 O 10 2 we performed Hartree-Fock and DFT calculations with standard basis sets (6-31G ŁŁ ) and basis sets including additional diffuse functions. For a single unit we found that in the case of Hartree-Fock, the highest occupied orbitals had negative orbital energies, whereas in the case of DFT the HOMO-orbital energy and many energies below showed positive values, i.e.…”