Chain structures in sulphates

Gorogotskaya, L. I.; Bokii, G. B.

doi:10.1007/bf00739500

Cited by 2 publications

(4 citation statements)

References 7 publications

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“…Cu 2+ has a square planar arrangement in the di-hydrate (CSÁW 2 ) while the tri-hydrate (CSÁW 3 ) has a square pyramidal geometry with an axial water molecule. Although these structures do not reflect the observed crystal structures of anhydrous 48,64 and pentahydrate 49,50,65 CuSO 4 , these models are best suited for a fair comparison with the mixed adsorbent. In all of the mixed adsorbent structures, Cu 2+ favors a square planar arrangement with the ligands (although slightly distorted in some cases) as opposed to the expected John Teller 82 distorted octahedral geometry suggested by its d9 electronic configuration.…”

Section: Cu 2+ Coordinationmentioning

confidence: 86%

“…Surface interactions of silica are primarily modeled as interactions with an isolated silanol on the silica surface. Many clusters have been proposed to model the surface silanol group, ranging from the simplest H 3 SiOH 45,46 to larger cage like structures derived from the class of recently synthesized 47 and characterized [48][49][50][51] hydridosilsesquioxanes. However, the type of model to be considered for accurate predictions is strongly dependant on the property being investigated.…”

Section: Modeling Approachmentioning

confidence: 99%

“…For comparison, pure CuSO 4 is modeled as a single ion pair rather than alternating chains of corner-sharing SO 4 2À tetrahedra and octahedrally coordinated Cu 2+ sites observed in its crystal structure. 48,64 The possibility of variable coordination numbers in the Cu 2+ ion offers several possibilities for its interaction with SiO 2 in the mixed adsorbent. Hence, the cluster that best represents the mixed adsorbent is evaluated based on the total energies of the equilibrium geometries of four different configurations (structures SSQÁCS through SSQÁCS(IV) in The adsorption process is modeled as physisorption of NH 3 on the active site of the adsorbents.…”

Section: Modeling Approachmentioning

confidence: 99%

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DFT investigation of NH3 physisorption on CuSO4 impregnated SiO2

Ambati

Saiyed

Rankin

2012

Phys. Chem. Chem. Phys.

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In this quantum chemical investigation, NH(3) physisorption onto a model of copper sulfate impregnated silica is compared with pure silica and copper sulfate adsorbents. The physisorption process is modeled as direct binding of the NH(3) molecule to the adsorption site of the dry adsorbents and as displacement of a H(2)O molecule by NH(3) in the hydrated complexes. The surface of silica is represented by a hydroxyl group attached to a silsesquioxane cage, H(7)Si(8)O(12)(OH) and silica impregnated with CuSO(4) by the most stable configuration of the cluster containing a CuSO(4) ion pair placed adjacent to the silica cage. H(2)O is systematically added to the dehydrated adsorbents to investigate the role of water in NH(3) adsorption. Modeling hydrated environments of each type of adsorbent is focused on H(2)O molecules that directly coordinate with the active sites. The results indicate that the binding energy of adsorbing NH(3) onto the mixed adsorbent is greater than in pure silica. This enhanced binding in the mixed adsorbent is consistent with improved Brønsted acidity of the silanol in the presence of CuSO(4).

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Section: Cu 2+ Coordinationmentioning

confidence: 86%

Section: Modeling Approachmentioning

confidence: 99%

Section: Modeling Approachmentioning

confidence: 99%

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DFT investigation of NH3 physisorption on CuSO4 impregnated SiO2

Ambati

Saiyed

Rankin

2012

Phys. Chem. Chem. Phys.

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“…In the chains, the SO 4 tetrahedra have one O atom in common with a pair of NaO 6 octahedra. Chain motifs are encountered in the structures of many other sulfates (Gorogotskaya & Bokii, 1973).…”

Section: Data Reportsmentioning

confidence: 99%

Re-refinement of sodium ammonium sulfate dihydrate at 170 K

Eckhardt¹,

Wagner²,

Imming³

et al. 2020

IUCr Data

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The title compound, sodium ammonium sulfate dihydrate (SASD), NaNH4SO4·2H2O, a synthetic analogue of the mineral lecontite, is a well known ferroelectric. The crystal structure of the paraelectric phase has been re-refined at 170 K on the basis of single-crystal X-ray data, improving the previous study [Arzt & Glazer (1994). Acta Cryst. B50, 425–431] in terms of accuracy regarding hydrogen-atom positions and thus details of the hydrogen bonding. O—H...O and N—H...O hydrogen bonds between the principal building units [Na(OH2)4O2 octahedra, SO4 tetrahedra and ammonium cations] constitute a three-dimensional network structure.

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Chain structures in sulphates

Cited by 2 publications

References 7 publications

DFT investigation of NH3 physisorption on CuSO4 impregnated SiO2

DFT investigation of NH3 physisorption on CuSO4 impregnated SiO2

Re-refinement of sodium ammonium sulfate dihydrate at 170 K

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