The Crystal Structure of Anhydrous Sodium Sulfate Na2SO4

Zachariasen, W. H.; Ziegler, G. E.

doi:10.1524/zkri.1932.81.1.92

Cited by 12 publications

(9 citation statements)

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“…The anhydrous potassium rare-earth metal oxosulfates show a coordination sphere around the alkali-metal cation erected by ten oxygen atoms from six oxosulfate anions in case of the triclinic examples [47,48] and seven terminal [SO 4 ] 2units in the monoclinic cases [49,50]. In the orthorhombic salt Na 2 [SO 4 ], the sodium cations show six oxygen atoms from five oxosulfate groups as next neighbors [51], while in its decahydrate Na 2 [SO 4 ] • 10 H 2 O, Na + is only surrounded by six water molecules octahedrally [52] (Figure 6). While NaY[SO4]2 • H2O exhibits only one singular crystallographic [SO4] 2− anion, its anhydrate has two different ones of them (Figure 7).…”

Section: Resultsmentioning

confidence: 99%

Hydrothermal Synthesis, Crystal Structure, and Spectroscopic Properties of Pure and Eu3+-Doped NaY[SO4]2 ∙ H2O and Its Anhydrate NaY[SO4]2

et al. 2021

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The water-soluble colorless compound NaY[SO4]2 ∙ H2O was synthesized with wet methods in a Teflon autoclave by adding a mixture of Na2[SO4] and Y2[SO4]3 ∙ 8 H2O to a small amount of water and heating it up to 190 °C. By slow cooling, single crystals could be obtained and the trigonal crystal structure of NaY[SO4]2 ∙ H2O was refined based on X-ray diffraction data in space group P3221 (a = 682.24(5) pm, c = 1270.65(9) pm, Z = 3). After its thermal decomposition starting at 180 °C, the anhydrate NaY[SO4]2 can be obtained with a monoclinic crystal structure refined from powder X-ray diffraction data in space group P21/m (a = 467.697(5) pm, b = 686.380(6) pm, c = 956.597(9) pm, β = 96.8079(5), Z = 2). Both compounds display unique Y3+-cation sites with eightfold oxygen coordination (d(Y–Os = 220–277 pm)) from tetrahedral [SO4]2− anions (d(S–O = 141–151 pm)) and a ninth oxygen ligand from an H2O molecule (d(Y–Ow = 238 pm) in the hydrate case. In both compounds, the Na+ cations are atoms (d(Na–Os = 224–290 pm) from six independent [SO4]2− tetrahedra each. Thermogravimetry and temperature-dependent PXRD experiments were performed as well as IR and Raman spectroscopic studies. Eu3+-doped samples were investigated for their photoluminescence properties in both cases. The quantum yield of the red luminescence for the anhydrate NaY[SO4]2:Eu3+ was found to be almost 20 times higher than the one of the hydrate NaY[SO4]2 ∙ H2O:Eu3+. The anhydrate NaY[SO4]2:Eu3+ exhibits a decay time of about τ1/e = 2.3 µm almost independent of the temperature between 100 and 500 K, while the CIE1931 color coordinates at x = 0.65 and y = 0.35 are very temperature-consistent too. Due to these findings, the anhydrate is suitable as a red emitter in lighting for emissive displays.

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Section: Resultsmentioning

confidence: 99%

Hydrothermal Synthesis, Crystal Structure, and Spectroscopic Properties of Pure and Eu3+-Doped NaY[SO4]2 ∙ H2O and Its Anhydrate NaY[SO4]2

et al. 2021

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“…The diffraction pattern of the dry CNCs sample shows a highly crystalline phase corresponding to the Iβ polymorph of cellulose (space group P 112 1 ), which consists of chains of pyranosidic rings directed along the c-axis (panel (d) in Figure 8), and in which the sharp reflections (012) and (102) point to the random orientation of the crystallites in the sample [55]. In addition to the cellulose phase, the dry CNCs sample contains 22% wt of Na 2 SO 4 , as evidenced by the diffraction pattern showing two different Na 2 SO 4 polymorphs with space groups Cmcm and Fddd [56,57]. Panel (a) in Figure 8 illustrates the contribution of each of the three phases to the experimental powder pattern of the dry CNCs sample.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Moisture on Cellulose Nanocrystals Intended as a High Gas Barrier Coating on Flexible Packaging Materials

et al. 2017

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Cellulose nanocrystals (CNCs) exhibit outstanding gas barrier properties, which supports their use as a biobased and biodegradable barrier coating on flexible food packaging materials. As highly hydrophilic biopolymers, however, CNCs have a strong sensitivity to water that can be detrimental to applications with fresh foods and in moist conditions due to the loss of barrier properties. In this work, the oxygen and water vapor permeability of polyethylene terephthalate (PET) films coated with CNCs obtained from cotton linters were measured at varying levels of relative humidity, both in adsorption and desorption, and from these data, the diffusion and solubility coefficients were estimated. Therefore, the characterization of CNCs was aimed at understanding the fundamentals of the water-CNCs interaction and proposing counteractions. The CNCs' moisture absorption and desorption isotherms at 25 • C were collected in the range of relative humidity 0-97% using different techniques and analyzed through GAB (Guggenheim-Anderson-de Boer) and Oswin models. The effects of moisture on the water status, following the freezable water index, and on the crystal structure of CNCs were investigated by Differential Scanning Calorimetry and by X-ray Powder Diffraction, respectively. These findings point to the opportunity of coupling CNCs with hydrophobic layers in order to boost their capabilities as barrier packaging materials.

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“…They found that within silicate and germanate compounds, the olivine structure type can accommodate a wider spectrum of octahedral cation sizes in contrast to other structure types. Despite earlier expectations from cation radius assessments indicating that chromous orthosilicate would adopt the olivine structure, Cr2SiO4 was observed to crystallize in the thenardite-type structure instead [3][4][5]. Typically, the latter is associated with cations that are larger than those present in silicates and germanates exhibiting the olivine structure type.…”

Section: Introductionmentioning

confidence: 86%

“…Cadmium silicates adopt specific structures at room temperature which are: monoclinic CdSiO3, orthorhombic Cd2SiO4, and tetragonal Cd3SiO5. The initial structure (CdSiO3) is classified within the P121/c1 space group, characterized by three asymmetrically distorted (CdO6) 4octahedra arranged in slabs parallel to the (0 1 0) plane, with unbranched silicate chains serving as separators. These chains are composed of regular cornersharing (SiO4)4-tetrahedra [8].…”

Section: Introductionmentioning

confidence: 99%

Pressure-Driven Responses in Cd2SiO4 and Hg2GeO4 Minerals: A Comparative Study

Singh,

Kanchana,

Errandonea

et al. 2024

Preprint

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The structural, elastic, and electronic properties of orthorhombic Cd2SiO4 and Hg2GeO4 were examined under varying pressure conditions using first-principles calculations based on densi-ty-functional theory employing the projector augmented wave method. The obtained cell pa-rameters at 0 GPa were found to align well with existing experimental data. We delved into the pressure-dependence of normalized lattice parameters and elastic constants. In Cd2SiO4, all lat-tice constants decreased as pressure increased, whereas in Hg2GeO4, parameters a and b de-creased while parameter c increased under pressure. Employing the Hill average method, we calculated the elastic moduli and Poisson’s ratio up to 10 GPa, noting an increase with pressure. Evaluation of ductility/brittleness under pressure indicated both compounds remained ductile throughout. We also estimated elastic anisotropy and Debye temperature under varying pres-sures. Cd2SiO4 and Hg2GeO4 were identified as indirect band gap insulators, with estimated band gaps of 3.34 eV and 2.09 eV, respectively. Interestingly, Cd2SiO4 exhibited a significant increase in band gap with increasing pressure, whereas the band gap of Hg2GeO4 decreased under pres-sure, revealing distinct structural and electronic responses despite their similar structures.

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The Crystal Structure of Anhydrous Sodium Sulfate Na₂SO₄

Cited by 12 publications

References 0 publications

Hydrothermal Synthesis, Crystal Structure, and Spectroscopic Properties of Pure and Eu3+-Doped NaY[SO4]2 ∙ H2O and Its Anhydrate NaY[SO4]2

Hydrothermal Synthesis, Crystal Structure, and Spectroscopic Properties of Pure and Eu3+-Doped NaY[SO4]2 ∙ H2O and Its Anhydrate NaY[SO4]2

The Effect of Moisture on Cellulose Nanocrystals Intended as a High Gas Barrier Coating on Flexible Packaging Materials

Pressure-Driven Responses in Cd<sub>2</sub>SiO<sub>4</sub> and Hg<sub>2</sub>GeO<sub>4</sub> Minerals: A Comparative Study

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