Low temperature powder diffraction and DFT solid state computational study of hydrogen bonding in NH₄VO₃

Abstract

The crystal structure of NH 4 VO 3 was refined by the geometry optimization done by total energy minimization in solid state using DFT/plane waves approach. The lattice parameters were derived by the Le Bail technique from the low temperature X-ray (40-293 K) and synchrotron (100-293 K) powder diffraction data. The structure is formed by the infinite chains of irregular VO 4 tetrahedra running approximately parallel to the caxis, which are interlinked by the ammonium ions placed between them. The ammonium ions link to the [VO 4 ] ∞ chains through one linear, one bifurcated and two trifurcated N-H…O hydrogen bonds. Considering their stability there are six distinct N-H…O hydrogen bonds: two strong with the N-H…O bond angles close to the straight, two medium with the bond angles of 123° and 148° and two very bent (105° and 107°) and hence weak hydrogen bonds. There is a reasonable agreement between the energies of the stretching ν(NH) modes estimated using the optimised N…O contact distances and those obtained experimentally.

Bis(4-methylanilinium) and bis(4-iodoanilinium) pentamolybdates from laboratory X-ray powder data and total energy minimization

“…As part of our ongoing study of organoammonium polymolybdates (Lasocha et al, 1995;Łasocha & Schenk, 1997;Wlodarczyk-Gajda et al, 2007;Gaweł & Łasocha, 2007;Łasocha et al, 2008, 2009Oszajca et al, 2010Oszajca et al, , 2012, the two new title pentamolybdate compounds, bis(4-methylanilinium) pentamolybdate, (I), and bis(4-iodoanilinium) pentamolybdate, (II), were synthesized. Since the compounds obtained only formed powders, their crystal structures were solved from laboratory powder diffraction data and optimized by total energy minimization in the solid state (see, for example, Smrčok et al, 2008Smrčok et al, , 2009Smrčok et al, , 2010; Le Bail & Smrčok, 2011; Oszajca et al, 2012).…”

Redetermination of ammonium metavanadate

“…The most precise structure report of NH 4 VO 3 up to date is probably that by Smrčok et al (2009), based on laboratory/ synchrotron temperature-variable X-ray powder diffraction data combined with solid state DFT calculations. However, these authors commented that they made 'unsuccessful attempts to grow a single-crystal suitable for single-crystal neutron diffraction'.…”

“…Indeed, only one single-crystal study based on four-circle diffractometer data may be retrieved from the literature (Hawthorne & Calvo, 1977). This longstanding X-ray study reported the structure at a standard resolution, d = 0.84 Å , and, as mentioned by Smrčok et al (2009), 'the positions [of the hydrogen atoms] are not suffi-ciently accurate to be directly used in calculations of vibrational spectra'.…”

Solar Cell Materials by Design: Hybrid Pyroxene Corner‐Sharing VO4 Tetrahedral Chains

“…Cs [ [57] show that ammonium NH 4 + displays one moderate bifurcated hydrogen bond and two trifurcated N-H-O hydrogen bonds. This leads to the formation of two strong hydrogen bonds.…”