Activités Raman et Infrarouge des Cristaux Piezoélectriques BeSO₄, 4H₂O et BeSO₄, 4D₂O. 2—Activité Raman des Modes Polaires

Abstract

The crystals BeSO4 4H20 and BeSO,, 4D20 were investigated by Raman scattering (4000 to 4 cm-') and both crystals exhibited TO-LO splittings, a confirmation of their piezoelectric lattice. Distinctive oblique modes, with an E and Bz mixed character were observed. Effective dynamical charges were calculated. An electroptic effect was displayed.Les cristaux BeSO4, 4H20 et BeSO,, 4D20 CtudiLs par diffusion Raman (4000 a 4 cm-') montrent tous deux des Lclatements TO-LO qui confirment leur structure a caractbre piezoklectrique. Des modes obliques distincts montrent un caractbre mixte B z et E. Des charges dynamiques effectives ont Ct6 calculkes. Un effet Clectrooptique a 6th mis en kvidence,

Hydration of beryllium(ii) in aqueous solutions of common inorganic salts. A combined vibrational spectroscopic and ab initio molecular orbital study

“…The assignment of the modes were made on the basis of the results published for other solid hydrated sulfate salts 38 and from a detailed single crystal structure study of BeSO 4 •4H 2 O. 39, 40 The modes are split in the solid state due to site symmetry and the factor group splitting and the factor group analysis may be found elsewhere. 39,40 In crystalline BeSO 4 •4H 2 O, n 1 is obtained at 544 cm -1 at slightly higher wavenumbers than in solution (n 1 BeO 4 (aq) = 531 cm -1 ).…”

“…39, 40 The modes are split in the solid state due to site symmetry and the factor group splitting and the factor group analysis may be found elsewhere. 39,40 In crystalline BeSO 4 •4H 2 O, n 1 is obtained at 544 cm -1 at slightly higher wavenumbers than in solution (n 1 BeO 4 (aq) = 531 cm -1 ).…”

Molecular Dynamics and X-Ray Diffraction Study of Aqueous Beryllium(II) Chloride Solutions

“…F o r a com p ariso n w ith these divalent ions, it is o f interest to exam ine th e h y d ratio n p h en o m e non o f the sm aller Be2+ in aqu eo u s solutions. The structure o f Be(II) h y d rates in th e solid state has been established from X -ray [5] and n eu tro n [6] diffraction studies and from in frared and R am an spectra [7] In o rd er to check the consistency betw een experi m ents and M D sim ulations, an X -ray scattering m easurem ent o f an aqueous 1.1 m olal BeCl2 solu tion was p erform ed w ith a slight excess o f H + ions because Be2+ hydrolyses to form polynuclear species Be3(O H )3+ and Be2(O H )3+ at hig h er pH [16,17]. In ad d ition, a 5.3 m olal BeCl2 solution was m easured in o rd er to em phasize the interactions w ithin the h y d ration structure o f Be2+ having small X -ray scattering am plitudes.…”

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

“…The beryllium tetrahedra, [BeO 4 ], are reported to exhibit lattice vibrations ν 1 ′, ν 2 ′, ν 3 ′ and ν 4 ′ in the range of 540, 250-300, 700-900 and 350 cm -1 , respectively [16,17]. The site group analysis of the [BeO 2 (H 2 O) 2 ]tetrahedra in K 2 Be(SO 4 ) 2 ·2H 2 O and K 2 Be(SeO 4 ) 2 ·2H 2 O (Be 2+ ions in C 1 site symmetry) predicts: ν 1 ′(A 1 ) -A, ν 2 ′(E) -2A, ν 3 ′(F 2 ) and ν 4 ′(F 2 ) -each 3A.…”