Phase transition and high-pressure behavior of ulexite, a potential aggregate in radiation-shielding concretes

Comboni, Davide; Pagliaro, Francesco; Gatta, G. Diego; Lotti, Paolo; Battiston, Tommaso; Merlini, Marco; Hanfland, Michael

doi:10.1016/j.conbuildmat.2021.123188

Cited by 11 publications

(22 citation statements)

References 45 publications

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“…the increase in the coordination number of the only boron B site in planar trigonal coordination from III to IV. Such an increase in the B coordination number was observed also in kurnakovite (Pagliaro et al 2021) and ulexite (Comboni et al 2021a). Moreover, considering the phase-transition pressure in meyerhofferite (⁓3.3 GPa), inyoite (⁓8.6 GPa) and kurnakovite (⁓10.2…”

Section: Concluding Remarks and Comparison With Previous Studiesmentioning

confidence: 55%

“…As all the hydrous borates investigated so far at high pressure (Pagliaro et al 2021, Comboni et al 2020a, Comboni et al 2021a, Lotti et al 2017, even inyoite experiences a P-induced phase transition. In inyoite, the transition at high pressure (between 8.3-8.9 GPa) is a first-order and isosymmetric transformation, which leads to a less compressible high-pressure polymorph (i.e., KV0…”

Section: Concluding Remarks and Comparison With Previous Studiesmentioning

confidence: 96%

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High-pressure behaviour and atomic-scale deformation mechanisms in inyoite, CaB3O3(OH)5·4H2O

et al. 2022

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The compressional behaviour of inyoite, ideally CaB3O3(OH)5•4H2O, has been studied by an insitu high-pressure single crystal X-ray experiment, at the ESRF large scale facility, up to 19.80(5) GPa. Inyoite undergoes a first-order phase transition to inyoite-II, bracketed between 8.25(5) and 8.86(5) GPa, with a large volume discontinuity (ΔV⁓7.5%). The structure of the high-pressure polymorph has not been solved due to a significant decrease in the number of Bragg reflections.The isothermal bulk modulus (KV0 = β −1 P0,T0, where βP0,T0 is the volume compressibility coefficient) of inyoite was found to be KV0 = 26.9(8) GPa, whereas in inyoite-II the KV0 value increases to 52(5) GPa. The increase of the bulk modulus is paired with a sharp decrease of the anisotropic compressibility, as shown by the magnitude of the Eulerian finite unit-strain ellipsoid with: ε1:ε2:ε3 = 3.5:2.1:1 in inyoite and ε1:ε2:ε3 =1.5:1.1:1 in inyoite-II. The P-induced deformation mechanisms controlling, at the atomic scale, the bulk compression of inyoite are here described on the basis of a series of structure refinements.

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Section: Concluding Remarks and Comparison With Previous Studiesmentioning

confidence: 55%

Section: Concluding Remarks and Comparison With Previous Studiesmentioning

confidence: 96%

High-pressure behaviour and atomic-scale deformation mechanisms in inyoite, CaB3O3(OH)5·4H2O

et al. 2022

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“…Comparing the unit‐cell volumes of the low‐ and high‐ P polymorphs, a difference of approximately 3.5% is observed (Table 1): this is comparable to what was observed in colemanite (CaB 3 O 4 (OH) 3 ·H 2 O, Δ V ∼ 3.4% at 14.5 GPa 22 ) and is rather modest when compared to other hydrated borates (e.g., meyerhofferite CaB 3 O 3 (OH) 5 ·H 2 O, Δ V ∼ 10% at 3 GPa 24 ). The elastic parameters refined with EOS‐FIT7‐GUI software 39 revealed that jadarite is a relatively stiff hydrous borate, with a bulk modulus of approximately 55 GPa (Table 3), higher than ulexite (NaCaB 5 O 6 (OH) 6 ·5H 2 O, 37 GPa 25 ) and kernite (Na 2 B 4 O 6 (OH) 3 ·3H 2 O, 29 GPa 23 ) but lower than colemanite (CaB 3 O 4 (OH) 3 ·H 2 O, 67 GPa 22 ).…”

Section: Resultsmentioning

confidence: 99%

“…), the H 2 O molecules were key players during the phase transition, as they could be seen as bond‐valence moderators (or bond‐strength transformers 43 ). Indeed, during the phase transition of the aforementioned borates, at least a fraction of the planar triangular boron groups transforms to tetrahedra by making a new bond with an H 2 O molecule 21,24–26 . However, as jadarite does not contain molecular H 2 O but only one hydroxyl group per formula unit, its transformation path does not follow those of the aforementioned hydrous borates, leaving the boron sites with the same coordination scheme in the low‐ and high‐ P polymorphs.…”

Section: Resultsmentioning

confidence: 99%

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High‐pressure behavior and phase transition of jadarite, a promising B and Li mineral commodity

et al. 2022

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The high‐pressure behavior of a natural jadarite (ideally LiNaSiB3O7(OH), a ∼ 6.76 Å, b ∼ 13.80 Å, c ∼ 7.69 Å, β = 124.09°, space group P21/c) has been studied by in situ single‐crystal and powder synchrotron X‐ray diffraction up to 20 GPa, with a diamond anvil cell and using He as a hydrostatic pressure‐transmitting fluid. Between 16.57(5) and 17.04(5) GPa, jadarite undergoes a first‐order iso‐symmetric phase transition, which is reconstructive in character, with a ΔV of approximately ‐3%. The structure of the high‐pressure polymorph was solved and refined (to R1 ∼ 4%). The isothermal bulk modulus of the low‐P polymorph of jadarite is KV0 = 55.0(5) GPa (βV0 = 0.0182(2) GPa–1), and its P‐derivative is 3.84(9). The compressional anisotropy, derived along the three main crystallographic directions, is modest, with βa0:βb0:βc0 = 1.23:1:1.23. The P‐induced deformation mechanisms at the atomic scale, which lead to phase transition, are described.

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On the crystal-chemistry of inderite, Mg[B3O3(OH)5](H2O)4·H2O

Gatta,

Capelli,

Comboni

et al. 2024

Phys Chem Minerals

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The crystal chemistry of inderite, a hydrous borate with known ideal formula MgB3O3(OH)5·5H2O from the Kramer deposit, was re-investigated by electron probe micro-analysis in wavelength dispersive mode, laser ablation-(multi collector-)inductively coupled plasma-mass spectrometry and single-crystal neutron diffraction. The chemical data prove that the real composition of the investigated inderite is substantially identical to the ideal one, with insignificant content of potential isomorphic substituents, so that, excluding B, inderite does not contain any other industrially-relevant element (e.g., Li concentration is lower than 2.5 wt ppm, Be or REE lower than 0.1 wt ppm). The average δ11BNIST951 value of ca. − 7 ‰ lies within the range of values in which the source of boron is ascribable to terrestrial reservoirs (e.g., hydrothermal brines), rather than to marine ones. Neutron structure refinements, at both 280 and 10 K, confirm that the building units of the structure of inderite consist of: two BO2(OH)2 tetrahedra (B-ion in sp3 electronic configuration) and one BO2(OH) triangle (B-ion in sp2 electronic configuration), linked by corner-sharing to form a (soroborate) B3O3(OH)5 ring, and a Mg-octahedron Mg(OH)2(OH2)4. The B3O3(OH)5 ring and the Mg-octahedron are connected, by corner-sharing, to form an isolated Mg(H2O)4B3O3(OH)5 (molecular) cluster. The tri-dimensional edifice of inderite is therefore built by heteropolyhedral Mg(H2O)4B3O3(OH)5 clusters mutually connected by H-bonds, mediated by the zeolitic (“interstitial”) H2O molecules lying between the clusters, so that the correct form of the chemical formula of inderite is Mg[B3O3(OH)5](H2O)4·H2O, rather than MgB3O3(OH)5·5H2O. All the thirteen independent oxygen sites of the structure are involved in H-bonding, as donors or as acceptors. This confirms the pervasive nature and the important role played by the H-bonding network on the structural stability of inderite. The differences between the crystal structure of the two dimorphs inderite and kurnakovite are discussed.

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Phase transition and high-pressure behavior of ulexite, a potential aggregate in radiation-shielding concretes

Cited by 11 publications

References 45 publications

High-pressure behaviour and atomic-scale deformation mechanisms in inyoite, CaB3O3(OH)5·4H2O

High-pressure behaviour and atomic-scale deformation mechanisms in inyoite, CaB3O3(OH)5·4H2O

High‐pressure behavior and phase transition of jadarite, a promising B and Li mineral commodity

On the crystal-chemistry of inderite, Mg[B3O3(OH)5](H2O)4·H2O

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