Knop, Osvald;
Cameron, T. Stanley;
Deraniyagala, S. P.;
Adhikesavalu, D.;
Falk, Michael
Infrared spectra of the ammonium ion in crystals. Part XIII. Crystal structure of (NH4)2[AlF5(H2O)] and NH3D+ probe-ion spectra in (NH4)2[AlF5(H2O)], NH4AlF4, and (NH4)3ZnCl5, with remarks on structural filiation of AMF4 fluorides
Sie können Bookmarks mittels Listen verwalten, loggen Sie sich dafür bitte in Ihr SLUB Benutzerkonto ein.
Medientyp:
E-Artikel
Titel:
Infrared spectra of the ammonium ion in crystals. Part XIII. Crystal structure of (NH4)2[AlF5(H2O)] and NH3D+ probe-ion spectra in (NH4)2[AlF5(H2O)], NH4AlF4, and (NH4)3ZnCl5, with remarks on structural filiation of AMF4 fluorides
Beteiligte:
Knop, Osvald;
Cameron, T. Stanley;
Deraniyagala, S. P.;
Adhikesavalu, D.;
Falk, Michael
Erschienen:
Canadian Science Publishing, 1985
Erschienen in:
Canadian Journal of Chemistry, 63 (1985) 2, Seite 516-525
Beschreibung:
<jats:p> The crystal structure of (NH<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub>AlF<jats:sub>5</jats:sub>•H<jats:sub>2</jats:sub>O = (NH<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub>[AlF<jats:sub>5</jats:sub>(H<jats:sub>2</jats:sub>O)] (Pbcn, a = 10.192(4) Å, b = 8.037(2) Å, c = 7.844(1) Å, Z = 4) consists of isolated [AlF<jats:sub>5</jats:sub>(H<jats:sub>2</jats:sub>O)]<jats:sup>2−</jats:sup> octahedral and NH<jats:sub>4</jats:sub><jats:sup>+</jats:sup> ions. The octahedra are linked by [Formula: see text] bonds to form zigzag chains parallel to c and the chains are cross-linked by normal [Formula: see text] hydrogen bonds to the NH<jats:sub>4</jats:sub><jats:sup>+</jats:sup> ions. The ir characteristics of the hydrogen bonds in this and the other two title compounds were probed with the NH<jats:sub>3</jats:sub>D<jats:sup>+</jats:sup> ion between 10 and 293 K. The probe-ion spectra confirm the C<jats:sub>1</jats:sub> symmetry of the ammonium ion in (NH<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub>[AlF<jats:sub>5</jats:sub>(H<jats:sub>2</jats:sub>O)] and point to [Formula: see text] bonding of moderate strength. For NH<jats:sub>4</jats:sub>AlF<jats:sub>4</jats:sub> the spectra agree with the expectation from the known crystal structure of both the ordered and the disordered phase, but the transition at ~150 K is not evident in the evolution of the spectra with temperature. Detailed assignment of the ND stretching and bending component absorptions of NH<jats:sub>3</jats:sub>D<jats:sup>+</jats:sup> is not possible for (NH<jats:sub>4</jats:sub>)<jats:sub>3</jats:sub>ZnCl<jats:sub>5</jats:sub> = (NH<jats:sub>4</jats:sub>)<jats:sub>3</jats:sub>(ZnCl<jats:sub>4</jats:sub>)Cl. However, the unusually low frequencies of two of the components of the ND stretching absorptions in this crystal indicate the existence of [Formula: see text] bonds stronger than those in NH<jats:sub>4</jats:sub>Cl. The filiation of the known AMF<jats:sub>4</jats:sub> structures deriving from TlAlF<jats:sub>4</jats:sub> is presented in terms of two-colour space groups. </jats:p>