Structural phase transitions in Ni(ClO4)2.6H2O in temperature range 100–375 K

Novaković, L.; Dojčilović, Jablan; Napijalo, M.M.; Napijalo, M.Lj.; Lazar, Dolores Ribeiro Ricci; Ribár, Β.

doi:10.1016/0038-1098(89)90187-7

Cited by 5 publications

(2 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…38 If the twofold screw axis ͑out-of-plane of Fig. 1͒ is retained during this expansion, as for ZnHP, 15 the z component of the O-O distances increases by ⌬c/2.…”

Section: The Hindering Potential In Phase I and Iimentioning

confidence: 99%

See 1 more Smart Citation

Hydrogen dynamics in [Me(H2O)6](ClO4)2 with Me=Mg, Mn, Fe, Ni, and Zn investigated with quasielastic neutron scattering

Nöldeke

Asmussen

Press

et al. 2000

The Journal of Chemical Physics

View full text Add to dashboard Cite

The hydrogen dynamics in the metalhexahydrateperchlorates with Mg, Mn, Fe, Ni, and Zn as metal ions has been investigated with quasielastic neutron scattering. The water molecules perform 180°-flip motions on a picosecond time scale through a series of solid–solid phase transitions. In the highest temperature phase I and the subsequent phase II, rotational barriers of typically Ea=50 meV are found. These values are surprisingly small in view of the low symmetry of H2O molecules. The I → II phase transition has only very small effects on the hydrogen dynamics. At the transition into phase III an increase of the rotational barriers to typically Ea=250 meV is found. This is interpreted as the formation of weak hydrogen bonds. In phase I 180°-flip motions provide a complete description of the observed data. In phases II and III an extension of the dynamical model toward a stronger localization of hydrogen is required. A preference is given to a mechanism leading to a temporary blockade of the flip motions. In phase III of the Fe compound, the existence of crystallographically different sites for water molecules is inferred.

show abstract

“…38 If the twofold screw axis ͑out-of-plane of Fig. 1͒ is retained during this expansion, as for ZnHP, 15 the z component of the O-O distances increases by ⌬c/2.…”

Section: The Hindering Potential In Phase I and Iimentioning

confidence: 99%

“…While the a-and c-axes of ZnHP show a marked change at this transition, 15 this is not the case for NiHP. 38 III transition is a symmetry reducing deformation of the water ligand octahedron ͑MgHP; 32 NiHP; 30 ZnHP; 31 MnHP͒. 41 This changes the H 2 O-ClO 4 distances and may lead to the formation of hydrogen bonds.…”

Section: The Hindering Potential In Phase IIImentioning

confidence: 99%