Mg2KH(XO4)2·15H2O (X = P, As) containing acidic dimer units: Electrochemical impedance spectroscopy, IR spectroscopy and DSC studies

Pecovska-Gjorgjevich, M.; Stefov, Viktor; Najdoski, Metodija; Koleva, V.; Mentus, Slavko; Petruševski, Gjorgji

doi:10.1016/j.jallcom.2018.02.348

Cited by 5 publications

(8 citation statements)

References 29 publications

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“…2356 and 3009 cm -1 (IR) due to the presence of poorly ordered water similar to K-struvite and consistent with the high water loss at low temperature observed by TGA. As in the case of K-struvite, PO 4 stretching vibrations are observed at around 1017 cm -1 (FTIR) and 941, 998 and 1030 cm -1 (Raman) (Koleva et al, 2017;Koleva et al, 2015;Pecovska-Gjorgjevich et al, 2018;. Further PO 4 bending vibration is observed at 544 cm -1 (FTIR) and 560 cm -1 (Raman) (Koleva et al, 2017;Koleva et al, 2015;Pecovska-Gjorgjevich et al, 2018;.…”

Section: The Ftir Spectra In Figure S3c (Supplementary Material) Show...mentioning

confidence: 64%

Thermodynamic data for magnesium (potassium) phosphates

Lothenbach

Winnefeld

2019

Applied Geochemistry

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Section: The Ftir Spectra In Figure S3c (Supplementary Material) Show...mentioning

confidence: 64%

Thermodynamic data for magnesium (potassium) phosphates

Lothenbach

Winnefeld

2019

Applied Geochemistry

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“…3). The appearance of such a broad and intensive band is characteristic for all IR spectra of struvite, its analogues, and related compounds [1][2][3][4][5][6][7][8][9][10][11][12][13][14], irrespective of both types of the crystal system in which these compounds crystallize (orthorhombic, cubic or hexagonal) and the number of the crystallographically different water molecules available in their structures (one, two or four water molecules in cubic, hexagonal, and orthorhombic crystal structures, respectively). In fact, this is directly related to the existence of strong hydrogen bonds in the structures of these systems.…”

Section: Stretching Vibrations Of the Water Moleculesmentioning

confidence: 99%

“…Struvite-type and related compounds with the formula M I M II XO4·6H2O (M I = NH4, K, Rb, Cs and Tl; M II = Mg, Co and Ni; X = P and As) have been studied in our lab for many years, mainly from a spectroscopic point of view [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Generally, our investigations have been focused on the members of the struvite-type family belonging to the orthorhombic space group Pmn21 (C2v 7 ) [1-6, 8, 10].…”

Section: Introductionmentioning

confidence: 99%

Infrared and Raman spectra of cubic form of magnesium caesium arsenate hexahydrate

Stefov

Koleva

Najdoski

et al. 2018

Maced. J. Chem. Chem. Eng.

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Fourier transform infrared (FT-IR) spectra recorded at room temperature (RT) and at the boiling temperature of liquid nitrogen (LNT), as well as Raman spectra recorded at room temperature for the cubic polymorph of magnesium cesium arsenate hexahydrate (MgCsAsO4·6H2O) and its partially deuterated analogues, were interpreted with respect to the normal modes of the water molecules and the arsenate ions and water librations. The spectral characteristics of MgCsAsO4·6H2O were compared to the cubic form of the phosphate analogue. A spectral similarity between the two isostructural salts was established, except for the obvious differences due to the nature of the anions (AsO43– vs PO43–). The spectroscopic data for the uncoupled OD stretching mode of the matrix-isolated HDO molecules revealed that the hydrogen bonds formed in the arsenate salt were stronger than those in the phosphate. In the Raman spectrum of the protiated compound, only one very intensive band at 811 cm–1 was observed in the region of the stretching vibrations of the AsO43– ion, which was insensitive to deuteration. In accordance with the expectation, one band appeared in the same spectral range in the infrared spectra of the protiated and highly deuterated sample at 792 cm–1 and 810 cm–1, respectively, which can be attributed with certainty to the asymmetric stretching ν3(AsO4) modes.

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“…It should be mentioned here that in the spectra of the cubic form of MgCsAsO4•6H2O [13], the lowest frequency band in this region is observed at 1520 cm -1 which is a frequency lower than the one of the bending HOH vibration of gaseous water (1595 cm -1 ). Such bands have been observed in the spectra of the compounds with formula M I M II XO4•6H2O (M I = NH4, K, Rb, Cs, Tl; M II = Mg, Co, Ni; X= P, As) and they can be explained as due to second order transitions, Fermi type of resonance interactions (resonance interactions of overtones of lower frequency modes with δ(HOH) vibrations) or to coupling with low frequency lattice modes [8][9][10][11][12][13]. All these mechanisms are generally physically feasible and none of them (or their combination) should be neglected.…”

Section: Internal Vibrations Of Water Moleculesmentioning

confidence: 99%

“…With this contribution we continue the study of the vibrational spectra of arsenate crystal hydrates with the general formula M I MgAsO4•6H2O (M I = NH4, K, Rb, Tl) having struvite-type or closely related structures which have been a subject of our research in the last fifteen years [8][9][10][11][12][13]. Here, we have focused on rubidium and thallium representatives, MgRbAsO4•6H2O and MgTlAsO4•6H2O that are very little known.…”

Section: Introductionmentioning

confidence: 99%

Infrared and Raman spectra of magnesium ammonium phosphate hexahydrate (struvite) and its isomorphous analogues. X. Vibrational spectra of magnesium rubidium arsenate hexahydrate and magnesium thallium arsenate hexahydrate

Stefov

Koleva

Najdoski

et al. 2020

Maced. J. Chem. Chem. Eng.

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Polycrystalline samples of struvite-type MgRbAsO4·6H2O and MgTlAsO4·6H2O in both protiated and deuterated forms have been prepared for the first time by a precipitation method. Detailed analysis of their infrared (IR) and Raman (R) spectra recorded at room temperature (RT) and liquid nitrogen temperature (LNT) has been carried out and assignment of the vibrational bands has been proposed. The observed spectral pictures confirm the isostructurality of the two arsenate salts in agreement with the structural data. Similarly to other struvite-type and structure-related arsenate salts, the n1(AsO4) modes appear at higher frequencies than the n3(AsO4) vibrations. Low intensity and temperature sensitive bands that could be assigned as due to stretching Mg–O vibrations and n4(AsO4) modes are observed below 500 cm–1 in the LNT IR spectra of the studied compounds, at 472 cm–1 and 445 cm–1 for the rubidium analogue and at 470 cm–1 and 440 cm–1 for the thallium analogue. In the far-infrared and Raman spectra many bands are observed between 400 cm–1 and 200 cm–1, most of which are sensitive to deuteration, suggesting that they are not pure but coupled and can be related to n(Mg–Ow) modes. On the other hand, a band around 405 cm–1 in the spectra of the protiated compounds most probably is due to n2(AsO4) mode because of its frequency position, intensity and slight sensitivity to deuteration.

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Mg2KH(XO4)2·15H2O (X = P, As) containing acidic dimer units: Electrochemical impedance spectroscopy, IR spectroscopy and DSC studies

Cited by 5 publications

References 29 publications

Thermodynamic data for magnesium (potassium) phosphates

Thermodynamic data for magnesium (potassium) phosphates

Infrared and Raman spectra of cubic form of magnesium caesium arsenate hexahydrate

Infrared and Raman spectra of magnesium ammonium phosphate hexahydrate (struvite) and its isomorphous analogues. X. Vibrational spectra of magnesium rubidium arsenate hexahydrate and magnesium thallium arsenate hexahydrate

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