Potassium beryllium sulfate dihydrate, K2Be(SO4)2·2H2O: Crystal structure and infrared spectroscopy

Georgiev, M.; Wildner, Manfred; Stoilova, D.; Karadjova, V.

doi:10.1016/j.molstruc.2005.05.048

Cited by 10 publications

(7 citation statements)

References 27 publications

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“…The present paper continues our investigations on the structures and properties of beryllium salts [1][2][3][4][5][6][7][8]. The interest in the beryllium compounds is determined by their promising physical properties.…”

Section: Introductionsupporting

confidence: 52%

“…The X-ray powder diffraction data of the anhydrous double salts, K 2 Be(SO 4 ) 2 and K 2 Be(SeO 4 ) 2 , are compiled in tables 1 and 2. The selenate compound forms monoclinic crystals with lattice parameters: a Vibrational spectra (infrared and Raman) of K 2 Be(SO 4 ) 2 ·2H 2 O, K 2 Be(SeO 4 ) 2 ·2H 2 O and the respective anhydrous salts are presented in figures 3 and 4 (the infrared and Raman spectra of the dihydrates are commented in detail in our previous papers [7,8]). The free tetrahedral ions (XO 4 n-) under perfect T d symmetry exhibit four internal vibrations: ν 1 (A 1 ), the symmetric X−O stretching mode, ν 2 (E), the symmetric XO 4 bending modes, ν 3 (F 2 ) and ν 4 (F 2 ), the asymmetric X−O stretching and XO 4 bending modes, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…As far as the ν 3 ′ modes of the beryllium tetrahedra are concerned a strong overlapping of these modes with water librations occurs and the bands could not be assigned unambiguously. The broad band with two maxima at 770 and 746 cm -1 in the infrared spectrum of K 2 Be(SO 4 ) 2 ·2H 2 O transforms into a comparatively strong and narrow band at 765 cm -1 upon deuteration [8] and consequently the band at 770 cm -1 could be assigned ν 3 ′ (Fig. 3(a).…”

Section: Resultsmentioning

confidence: 99%

“…In our previous papers the crystal and molecular structures of the double salts, K 2 Be(SO 4 ) 2 ·2H 2 O and K 2 Be(SeO 4 ) 2 ·2H 2 O, as determined by single crystal X-ray diffraction and infrared spectroscopy, are reported [7,8]. In this paper we present and discuss the dehydration processes of the title compounds using the methods of thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC).…”

Section: Introductionmentioning

confidence: 99%

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Thermal dehydration of the double salts K₂Be(XO₄)₂·2H₂O (X = S, Se)

Georgiev¹,

Stoilova

Marinova

et al. 2006

Cryst. Res. Technol.

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Key words potassium beryllium sulfate dihydrate, potassium beryllium selenate dihydrate, enthalpy of dehydration, anhydrous potassium beryllium sulfate and selenate, lattice parameters, vibrational spectra. PACS 81.70.Pg, 61.10.Hz, 07.57.HmThe thermal dehydration of the title compounds was studied by TG, DTA and DSC methods and the enthalpies of dehydration were calculated (87.6 kJ mol -1 and 167.5 kJ mol -1 for the sulfate and selenate compound, respectively). The larger value of ∆H deh of K 2 Be(SeO 4 ) 2 ·2H 2 O is due to the stronger hydrogen bonds formed in the selenate as compared to those formed in the respective sulfate owing to the stronger proton acceptor capabilities of the SeO 4 2ions. The enthalpies of formation (∆H f 0 ) of the dihydrates are also calculated from the DSC measurements (-4467.4 kJ mol -1 and -3447.1 kJ mol -1 for the sulfate and selenate compound, respectively). The anhydrous double salt, K 2 Be(SO 4 ) 2 , forms tetragonal crystals with lattice parameters: a = 7.232(2) Å; c = 14.168(2) Å; V = 741.0 Å 3 , while the anhydrous salt, K 2 Be(SeO 4 ) 2 , forms monoclinic crystals with lattice parameters: a = 9.217(3) Å; b = 10.645(3) Å; c = 8.989(2) Å; β = 108.52(4)°; V = 836.2 Å 3 . Vibrational spectra (infrared and Raman) of both the dihydrates and the anhydrous compounds are also presented and discussed.

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Section: Introductionsupporting

confidence: 52%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermal dehydration of the double salts K₂Be(XO₄)₂·2H₂O (X = S, Se)

Georgiev¹,

Stoilova

Marinova

et al. 2006

Cryst. Res. Technol.

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“…Compared to that of the solid state, the Be–OSO 3 bond distance of the outer-sphere complex in 2a was significantly elongated by ∼0.3 Å upon immersion in solution, whereas CPMD simulations in the gas phase revealed a shortening of ∼0.1 Å. However, the solvation effect on sulfato inner-sphere complex 3a increases the Be–OSO 3 bond distance by ∼0.01 Å in comparison to the values observed in the structures of the disulfato beryllium anion [Be(SO 4 ) 2 (H 2 O) 2 ] 2– . In addition, the aqueous CPMD simulation of 3c reveals an average Be–Cl distance of ∼2.1 Å, in reasonable comparison to EXAFS measurements at 2.2 Å, whereas static optimization employing a polarizable continuum underestimates this value by 0.27–0.3 Å depending on the functional.…”

Section: Resultsmentioning

confidence: 99%

Ab InitioMolecular Dynamics Investigation of Beryllium Complexes

et al. 2020

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Structures of aqueous [Be(H2O)4] 2+ , its outer-sphere and inner-sphere complexes with F-, Cland SO4 2-, as well as dinuclear complexes with a [Be2(-OH)(-SO4)] + core have been studied through Car-Parrinello molecular dynamics (CPMD) simulations with the BLYP functional. According to constrained CPMD/BLYP simulations and pointwise thermodynamic integration, the free energy of deprotonation of [Be(H2O)4] 2+ and its binding free energy with Fare 9.6 kcal mol-1 and-6.2 kcal mol-1 , respectively, in good accord with available experimental data. The computed activation barriers for replacing a water ligand in [Be(H2O)4] 2+ with Fand SO4 2-, 10.9 kcal mol-1 and 13.6 kcal mol-1 , respectively, are also in good qualitative agreement with available experimental data. These ligand substitution reactions are indicated to follow associative interchange mechanisms with backside (SN2-like) attack of the anion relative to the aquo ligand it is displacing. Outperforming static DFT computations of the salient kinetic and thermodynamic quantities involving simple polarizable continuum solvent models, CPMD simulations are validated as a promising tool to study structures and speciation of beryllium complexes in aqueous solution.

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