The High‐Pressure Oxide Tb<sub>3</sub>O<sub>5</sub> and its Non‐Centrosymmetric Low‐Temperature Polymorph–A Comprehensive Study

Glätzle, Matthias; Janka, Oliver; Svitlyk, Volodymyr; Chernyshov, Dmitry; Bartsch, Manfred; Zacharias, H.; Pöttgen, Rainer; Huppertz, Hubert

doi:10.1002/chem.201804006

Cited by 8 publications

(4 citation statements)

References 69 publications

(61 reference statements)

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“…In the case of Tb (III), the deconvolution is more difficult due to poorly resolved signals. More specifically, the analysis of the Tb 4 d 5/2 signal tends to indicate that two forms of Tb may coexist at ~149 eV and 152–151 eV; the REE may coexist as bound Tb (III) but also under its oxidized form, i.e., Tb (IV), respectively [ 68 , 69 ].…”

Section: Resultsmentioning

confidence: 99%

Synthesis of a New Phosphonate-Based Sorbent and Characterization of Its Interactions with Lanthanum (III) and Terbium (III)

et al. 2021

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High-tech applications require increasing amounts of rare earth elements (REE). Their recovery from low-grade minerals and their recycling from secondary sources (as waste materials) are of critical importance. There is increasing attention paid to the development of new sorbents for REE recovery from dilute solutions. A new generation of composite sorbents based on brown algal biomass (alginate) and polyethylenimine (PEI) was recently developed (ALPEI hydrogel beads). The phosphorylation of the beads strongly improves the affinity of the sorbents for REEs (such as La and Tb): by 4.5 to 6.9 times compared with raw beads. The synthesis procedure (epicholorhydrin-activation, phosphorylation and de-esterification) is investigated by XPS and FTIR for characterizing the grafting route but also for interpreting the binding mechanism (contribution of N-bearing from PEI, O-bearing from alginate and P-bearing groups). Metal ions can be readily eluted using an acidic calcium chloride solution, which regenerates the sorbent: the FTIR spectra are hardly changed after five successive cycles of sorption and desorption. The materials are also characterized by elemental, textural and thermogravimetric analyses. The phosphorylation of ALPEI beads by this new method opens promising perspectives for the recovery of these strategic metals from mild acid solutions (i.e., pH ~ 4).

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Section: Resultsmentioning

confidence: 99%

Synthesis of a New Phosphonate-Based Sorbent and Characterization of Its Interactions with Lanthanum (III) and Terbium (III)

et al. 2021

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“…Cerium, praseodymium, and terbium, for example, form tetravalent (CeO 2 ) and mixed‐valent (e.g. Pr 7 O 12 ≡Pr III 4 Pr IV 3 O 12 ; Tb 3 O 5 ≡Tb III 2 Tb IV O 5 ; δ ‐Tb 11 O 20 ≡Tb III 5 Tb IV 7 O 20 ) oxides . Samarium, europium, and ytterbium, in contrast, form divalent oxides (SmO, EuO, YbO) and dihalides (REX 2 ; RE=Sm, Eu, Yb; X=F–I) .…”

Section: Figurementioning

confidence: 99%

An Unusual Valence State: Trivalent Europium in Intermetallic Eu₂Ir₃Al₉

Stegemann

Block

Klenner

et al. 2019

Chemistry A European J

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Eu2Ir3Al9, synthesized from the elements in tantalum tubes, is one of the rare examples for trivalent europium in the field of intermetallic compounds. The compound crystallizes in the Y2Co3Ga9‐type structure (space group Cmcm), with lattice parameters fitting in between the isostructural samarium and gadolinium compounds. In the crystal structure, the Eu atoms form Al3‐triangle‐centered honeycomb layers and exhibit a coordination number of 17 in the shape of a fivefold‐capped hexagonal prism (Eu@Ir6Al6+Al5). Magnetic measurements indicate an overall low susceptibility, in line with van Vleck paramagnetism caused by the Eu3+ cations. Fits of the susceptibility yield a coupling constant of λ=290(10) K and an effective magnetic moment of μeff=4.56(1) μB, in line with a slight hybridization of the 7F0 and 7F1 state. 151Eu Mössbauer spectroscopic investigations unambiguously prove the presence of solely Eu3+ in the bulk material.

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“…To be specific, the choice of Pna 2 1 or Pnma used to confuse the structure determination of AE 3 RE 2 (BO 3 ) 4 , , Ba 6–3 x Ln 8+2 x Ti 18 O 54 , and LaYbO 3 , and keeps confusing other compounds so far, such as RE 3 NbS 3 O 4 , CuAsS, E(δ)-RE 2 Si 2 O 7 , and so on. Moreover, disclosing the group–subgroup relationship and understanding the potential Pnma ↔ Pna 2 1 phase transition are essential to reveal and interpret multiple physical properties of materials, such as nonlinear optics, , ferroelectrics, − multiferroics, , and magnetism, which require multitechnique characterization to cross-validate and further achieve reliable results. On the other hand, the controversy of the triclinic F-type RE 2 Si 2 O 7 (Sm and Eu) lies in doubt whether such an intermediate and narrow-stability-range F phase exists between the orthorhombic E(δ) (Eu–Ho and Y) and the monoclinic G (La–Nd) phases. ,− The answer to this question is of importance for a better understanding of the structure–luminescence relationship of Ce 3+ -doped (Gd,La) 2 Si 2 O 7 , a high-temperature scintillator in the limelight, with a close average radius of RE 3+ to those of Sm 3+ and Eu 3+ .…”

Section: Introductionmentioning

confidence: 99%

On the Crystal Chemistry of RE₂Si₂O₇: Revisited Structures, Group–Subgroup Relationship, and Insights of Ce³⁺-Activated Radioluminescence

Chen

Zhou

et al. 2023

Chem. Mater.

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Polymorphic rare-earth disilicates RE 2 Si 2 O 7 (RE = La−Lu, Y, and Sc) are attractive materials as thermal barrier coatings and scintillators; however, the orthorhombic E(δ)-type (RE = Eu−Ho and Y) and the triclinic F-type (RE = Sm and Eu) remain structurally controversial hitherto. In this work, we revisit the crystal structures of E(δ)-RE 2 Si 2 O 7 (Pnma), F-RE 2 Si 2 O 7 (P1̅ ), and the monoclinic G-La 2 Si 2 O 7 (P2 1 /n) by X-ray single-crystal/ powder diffraction. The second-harmonic generation (SHG) and/ or the local-structure-sensitive VUV−UV−vis luminescence of Ce 3+ /Eu 3+ validate the structure determination. E(δ)-RE 2 Si 2 O 7 (RE = Eu−Ho) crystallizes in the centrosymmetric Pnma instead of the previous noncentrosymmetric Pna2 1 (a subgroup of Pnma).Increasing the RE 3+ radius results in structural transformations of the reconstructive-type E(δ) ↔ F and translationengleiche subgroup−group relationship F ↔ G (RE = La−Nd). More importantly, we perform a complete survey of 17 structure-types over 63 compounds of RE 2 Si 2 O 7 and their related transformations depending on the radius of RE 3+ . On the basis of these studies, one could (i) predict the potential polymorphs of RE 2 Si 2 O 7 , including the high-pressure phase and the RE 2 Si 2 O 7 solid solutions; (ii) correlate the coefficient of thermal expansion (CTE) with the crystal structure, and (iii) understand the unusual radioluminescence of (Gd,La) 2 Si 2 O 7 :Ce 3+ high-temperature scintillators.

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The High‐Pressure Oxide Tb₃O₅ and its Non‐Centrosymmetric Low‐Temperature Polymorph–A Comprehensive Study

Cited by 8 publications

References 69 publications

Synthesis of a New Phosphonate-Based Sorbent and Characterization of Its Interactions with Lanthanum (III) and Terbium (III)

Synthesis of a New Phosphonate-Based Sorbent and Characterization of Its Interactions with Lanthanum (III) and Terbium (III)

An Unusual Valence State: Trivalent Europium in Intermetallic Eu₂Ir₃Al₉

On the Crystal Chemistry of RE₂Si₂O₇: Revisited Structures, Group–Subgroup Relationship, and Insights of Ce³⁺-Activated Radioluminescence

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The High‐Pressure Oxide Tb3O5 and its Non‐Centrosymmetric Low‐Temperature Polymorph–A Comprehensive Study

Cited by 8 publications

References 69 publications

Synthesis of a New Phosphonate-Based Sorbent and Characterization of Its Interactions with Lanthanum (III) and Terbium (III)

Synthesis of a New Phosphonate-Based Sorbent and Characterization of Its Interactions with Lanthanum (III) and Terbium (III)

An Unusual Valence State: Trivalent Europium in Intermetallic Eu2Ir3Al9

On the Crystal Chemistry of RE2Si2O7: Revisited Structures, Group–Subgroup Relationship, and Insights of Ce3+-Activated Radioluminescence

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The High‐Pressure Oxide Tb₃O₅ and its Non‐Centrosymmetric Low‐Temperature Polymorph–A Comprehensive Study

An Unusual Valence State: Trivalent Europium in Intermetallic Eu₂Ir₃Al₉

On the Crystal Chemistry of RE₂Si₂O₇: Revisited Structures, Group–Subgroup Relationship, and Insights of Ce³⁺-Activated Radioluminescence