IR absorption spectroscopy of polarized states of the [D2O...D-OD2]+ ion in crystalline deuterodioxonium perchlorate

Карелин, А. И.; Nikitina, Z. K.

doi:10.1134/s0036023606110179

Cited by 2 publications

(13 citation statements)

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“…In the calculation, the P2 1 2 1 2 1 phase is stable, where H + shifts closer to one of the two bound water molecules, according to the Н 2 О…Н + -ОН 2 scheme. Note that a somewhat similar shift of D + was observed in [9] in the IR absorption spectrum, where the transition of the metastable typical of the metastable phase, is absent in the stable phase. Instead there is a broad, but not continuum, intense band of the ОD stretching vibrations of the D + -ОD 2 fragment with the maximum at 1980 cm -1 , which is similar to the stretching vibrational band of the D 3 О + cation.…”

Section: Resultssupporting

confidence: 58%

“…2. The band with the frequency of D O ClO + − orthorhombic phase a more stable crystalline phase forms whose IR absorption spectrum drastically differs from the initial spectrum [9]. The phase transition is irreversible.…”

Section: Resultsmentioning

confidence: 98%

“…Vibrational spectra are a very sensitive method to detect the reduction of symmetry [8]. Taking into account the existence of various points of view on the structure of 5 D O ClO + − can be found here [9]. The content of a heavy hydrogen isotope in DClO 4 ⋅2D 2 O is 99 at.…”

Section: Introductionmentioning

confidence: 99%

“…It was estimated as ν 1/2 ≥ 80 cm -1 . They become narrow if only the isotopic matrix is the stable phase: 3363 cm -1 (ν 1/2 = 21 cm -1 ) and 3404 cm -1 (ν 1/2 = 17 cm -1 )[9]. The obvious fact of the absence of the narrow maxima contradicts another no less obvious fact of spectral indistinguishability of water molecules.…”

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confidence: 96%

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Infrared spectroscopic estimation of H+ and D+ positions in the sructure of the orthorhombic crystals of H5O 2 + ClO 4 − and D5O 2 + ClO 4 −

Карелин

Nikitina

2015

J Struct Chem

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The crystalline samples of the orthorhombic phase of 5 2 4 Н O ClO + − (I) and 5 2 4 D O ClO + − (II) are examined by infrared (IR) absorption spectroscopy. Inaccuracies referring to the identification of II found in the literature are corrected. The work shows that a typical evidence of the crystallization of I is the doublet splitting ν(ОН) at 3232 cm -1 and 3340 cm -1 ; and a typical evidence of the crystallization of II is a similar doublet splitting ν(ОD) at 2391 cm -1 and 2484 cm -1 . In order to determine the doublet origin and to make clear how it depends on the concentration of hydrogen isotopes, specially prepared isotopically mixed crystalline samples of the composition 1 5 2 4 (H D ) O ClO x x + − − (III, x = 0.17-0.90) are studied. Observations of the concentration dependence of the doublet splitting are used to check the quality of the existing variants of the crystal structure of I. Agreement in the experiments with the samples of III is obtained when the structural model of the cation with the H + and D + positions in the center of a strong Н 2 О…Н + …ОН 2 and D 2 О…D + …ОD 2 hydrogen bond (HB) is used. Although we do not exclude the possibility of a symmetrical statistical distribution of H + and D + between two potential energy minima. The results of the spectroscopic analysis agree with the known data of the X-ray crystallographic analysis, showing that the crystals of I have a space symmetry group Pnma. At the same time, they disagree with the recently published data of theoretical calculations of the crystal structure of I (P2 1 2 1 2 1 ), these data showing that H + notably shifts from the center of the strong HB towards an oxygen atom of one of the two water molecules. INTRODUCTIONThe peak of interest in the structural analysis of crystalline hydrates of perchloric acid and some other strong acids was in the second half of the last century. At that period, the structure of some crystalline hydrates of perchloric acid, including the 5 2 4 H O ClO + − crystals with a melting point of 20.65 °C [1], was determined by the X-ray crystallography. At the final stage of the structure identification, the symmetry space groups Pnma and Pn2 1 a were found to be equally possible: the R-factor of 0.114 and 0.108 respectively. A preference was given to the centrosymmetric group, though, in particular, its Rfactor was higher. If there were the space group Pnma, then the H + proton would be in the center of crystallographic inversion, and, consequently, in the center of a strong Н 2 О…Н + …ОН 2 hydrogen bond. However, in the final chapter of [1] 222 and in the chapter, devoted to the X-ray crystallography data of [2], there was a note regarding the known limitations of the method used. This note indicates that the X-ray diffraction method does not allow the determination of the H + location: whether it is on the symmetry element or its opposite sides, occupying two statistically or dynamically related positions.Using the single crystal X-ray diffraction (XRD) data of [1], the IR and Raman spectra of 5 2 4 H...

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Section: Resultssupporting

confidence: 58%

Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 96%

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Infrared spectroscopic estimation of H+ and D+ positions in the sructure of the orthorhombic crystals of H5O 2 + ClO 4 − and D5O 2 + ClO 4 −

Карелин

Nikitina

2015

J Struct Chem

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“…The Н 2 O molecules in the cation are crystallographically equivalent, and each of them is deformed by two nonequivalent hydrogen bonds (HBs) with 4 ClO − anions. The oxygen-oxygen distances differ only slightly: О(4)-Н…О (1) 2.784(6) Å and О(4)-Н…О (3) 2.788 (7) Å.…”

Section: Introductionmentioning

confidence: 99%

Metastable crystalline phases of D5O 2 + ClO 4 − : Selective stabilization by addition of the light hydrogen isotope

Карелин

Nikitina

2014

J Struct Chem

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The crystallization products from the liquid phase of DClO 4 ⋅2D 2 O (99 at.% D) on a silver chloride substrate were investigated by IR absorption spectroscopy. The conditions of crystallization and heat treatment of the resulting crystal film of 5 2 4 D O ClO + − (I) were varied to detect signs of polymorphism. The results of the study indicate the existence of four metastable crystalline phases for I. It is shown that the chain of transformations of the metastable phases initiated by heat treatment is accompanied by disturbances of the symmetry of the symmetry of the 5 2 D O . + cation. The detected phase transformations are irreversible. The most stable metastable phase is isostructural with the well-known orthorhombic phase of 5 2 4 Н O ClO . + − The metastable nature of the orthorhombic phase is confirmed by the presence of a monotropic transition, which dramatically reduces the symmetry of the 5 2 D O . + cation. The polymorphismtypical of I disappears with the addition of more than 10 at.% of protium. Instead of the four metastable phases found for the deutertaed sample, only one orthorhombic phase crystallizes. Extraordinary stabilization by the addition of the protium isotope prevents polymorphic transition.

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IR absorption spectroscopy of polarized states of the [D2O...D-OD2]+ ion in crystalline deuterodioxonium perchlorate

Cited by 2 publications

References 12 publications

Infrared spectroscopic estimation of H+ and D+ positions in the sructure of the orthorhombic crystals of H5O 2 + ClO 4 − and D5O 2 + ClO 4 −

Infrared spectroscopic estimation of H+ and D+ positions in the sructure of the orthorhombic crystals of H5O 2 + ClO 4 − and D5O 2 + ClO 4 −

Metastable crystalline phases of D5O 2 + ClO 4 − : Selective stabilization by addition of the light hydrogen isotope

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