Synthesis, X-ray diffraction and vibrational study of silicates and germanates isostructural with kentrolite Pb2Mn2Si2O9

Gabelica-Robert, M.; Tarte, P.

doi:10.1016/0022-4596(79)90156-7

Cited by 16 publications

(4 citation statements)

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“…Li x MX 2 O 7 (M = Ti, Fe, V, Mn) compositions , are clearly, at first sight, non competitive positive electrode materials in terms of theoretical capacities to be delivered because of the weight penalty of two phosphate groups per transition metal. They provide, however, an interesting panel of crystal structure arrangements and electrochemical insertion mechanisms that deserve to be mentioned here.…”

Section: Alternative Polyanionic Structures and Compositions: Hydrate...mentioning

confidence: 99%

Polyanionic (Phosphates, Silicates, Sulfates) Frameworks as Electrode Materials for Rechargeable Li (or Na) Batteries

2013

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From Oxides to Ionically Conducting Polyanionic Frameworks as Positive Electrodes in Li Batteries 6553 2. The Early Days: The NASICON and Anti-NASICON Structures Used as Model Frameworks 6554 2.1. Structural Considerations 6554 2.2. The Inductive Effect: Tuning the M n+ /M (n−1)+ Redox Couple in the NASICON Structure by Changing the Chemical Nature of the XO 4 n− Groups 6555 2.3. Relative Positions of Various M n+ /M (n−1)+ Redox Couples (M = Fe, Ti, V, Nb) in NASICON-type Phosphates 6555 2.3.1. Position of the Ti 4+ /Ti 3+ Couple versus Li + /Li or Na + /Na 6555 2.3.2. Position of the Fe 3+ /Fe 2+ Couple versus Li + /Li or Na + /Na 6556 2.3.3. Position of the V n+ /V (n−1)+ Couples versus Li + /Li or Na + /Na 6556 2.4. Complex Redox Phenomena in Anti-NASI-CON Compositions Li x M 2 (PO 4 ) 3 (0 < x < 5 ; M = Fe, V) 6556 2.4.1. Li + Insertion into Monoclinic Fe 2 (SO 4 ) 3 , Li 3 Fe 2 (PO 4 ) 3 , and Li 3 Fe 2 (AsO 4 ) 3 6557 2.4.2. Li + Insertion/Extraction into Monoclinic Li 3 V 2 (PO 4 ) 3 6557 3. LiMPO 4 Compositions Based on the Olivine Structure: Fifteen Years of Great Achievements 6558 3.1. The Early Days: From an Academic Curiosity to First Industrial Realizations 6558 3.2. A Myriad of Synthesis Routes Developed for Optimal Electrochemical Response of LiMPO 4 Powders, Industrial Process Ability, and Cost Reduction 6559 3.2.1. Solid-State Syntheses 6559 3.2.2. Solution-Based Syntheses 6560 3.2.3. Carbon Coating and Purity Control of LiFePO 4 6562 3.3. The Highly Insulating LiMnPO 4 6562 3.4. Substitutions of Mn and/or Co for Fe in LiFePO 4 6563 3.5. Intrinsic Physicochemical Properties of LiFe-PO 4 and Mechanism of Li + Extraction 6565 3.5.1. Crystal Structure, Defects, e − Transport, Li + Diffusion 6565 3.5.2. Reactivity with Moisture and/or Air 6566 3.5.3. Mechanism 6567 4. Alternative Polyanionic Structures and Compositions: Hydrated Phosphates, Diphosphates, Alluaudites, Silicates, and Borates 6569 4.1. Fe 3+ /Fe 2+ Couple in Amorphous or Crystalline Iron Phosphates: FePO 4 •nH 2 O 6569 4.

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Section: Alternative Polyanionic Structures and Compositions: Hydrate...mentioning

confidence: 99%

Polyanionic (Phosphates, Silicates, Sulfates) Frameworks as Electrode Materials for Rechargeable Li (or Na) Batteries

2013

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“…The Pb2Fe2Ge209 compound has previously been synthesized in microcrystalline form and has been identified by powder X-ray diffraction as an analogue of the silicate mineral melanotekite, PbzFezSi209 (Gabelica-Robert & Tarte, 1979). In fact, the crystal structure of the silicate mineral itself was only recently solved in the correct space group, Pbcn, for a Pbz(Mn,Fe)2Si209 mixed composition along the kentrolite-melanotekite series (Moore et al, 1991), following an early attempt in the C2221 space group (Gabrielson, 1962).…”

Section: Commentmentioning

confidence: 99%

Pb₂Fe₂Ge₂O₉, the Germanate Analogue of the Silicate Mineral Melanotekite

Barbier¹,

Levy²

1998

Acta Crystallogr C

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The structure of dilead(II) diiron(III) digermanium(IV) oxide, with a minor (2Fe/Mg+Ge) substitution arising from the growth conditions, has been determined using flux-grown single crystals. Interesting features of the structure include an unsymmetrical splitting of the Pb site and a strong anisotropy of the bridging O atom of the Ge207 group, both of which also occur in the structure of the silicate mineral melanotekite, Pb2Fe2Si209. These structural features can be associated with the stereoactivity of the Pb 2÷ lone pairs, which is found to be less pronounced in the germanate than in the silicate structure. CommentThe Pb2Fe2Ge209 compound has previously been synthesized in microcrystalline form and has been identified by powder X-ray diffraction as an analogue of the silicate mineral melanotekite, PbzFezSi209 (Gabelica-Robert & Tarte, 1979). In fact, the crystal structure of the silicate mineral itself was only recently solved in the correct space group, Pbcn, for a Pbz(Mn,Fe)2Si209 mixed composition along the kentrolite-melanotekite series (Moore et al., 1991), following an early attempt in the C2221 space group (Gabrielson, 1962). The structure determination in Pbcn revealed a splitting of the Pb site in the Pb2(Mn,Fe)2Si209 structure, which was attributed to the stereoactive lone pair of the Pb 2÷ cation (Moore et al., 1991). Similar splitting of Pb sites has also been reported in the structures of other Pb 2+-containing compounds, such as PbFel2Oi9 (Moore et al., 1989) and PbAI2Si208 (Benna et al., 1996). In view of the difficulties encountered during the structure refinement of the melanotekite mineral [i.e. diffuse streaking in precession photographs, violations of space-group absences, non-positive definite displacement parameter for one O atom (Moore et al., 1991)], and because good-quality crystals of the PbzFezGe209 compound were available, it was decided to carry out the structure determination of the germanate analogue for comparison purposes. AbstractTrigallium phosphorus heptaoxide was synthesized by high-pressure hydrothermal synthesis. Its structure comprises PO4 tetrahedra and GaO5 trigonal bipyramids connected by edges to form Ga3Ol0 clusters. It is isotypic with Fe3PO7 and is the third known compound in the Ga-P-O system. © 1998 International Union of Crystallography Printed in Great Britain -all fights reserved Fig. 1. Perspective view of the Ga3PO7 structure projected along the c axis with the a axis horizontal and the b axis close to vertical. The GaO5 and PO4 polyhedra are represented as light and medium gray, respectively. 03 02 03 J~ O1 ~ Ga 03 02 02 Fig. 2. A view of the GaO5 and PO4 units. The displacement ellipsoids are plotted at the 90% probability level.

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“…antisymmetric (∼1000-1200 cm -1 ) stretching vibration of the Si-O-Si bridge (Lazarev, 1972;Gabelica-Robert and Tarte, 1979). Following Le Cléac'h and Gillet (1990), in lawsonite these vibrations start with ν s -Si-O-Si at 694 cm -1 accompanied by a group of SiO 3 stretching vibrations with a maximum at 935 cm -1 and end with ν as -Si-O-Si at 1047 cm -1 .…”

Section: Raman Spectroscopymentioning

confidence: 93%

T-induced displacive phase transition of end-member Pb-lawsonite

et al. 2016

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Pb-lawsonite, PbAl2[(OH)2|Si2O7]·H2O, space group Pbnm, was synthesized as crystals up to 15 μm × 5 μm × 5 μm in size by a piston cylinder technique at a pressure of ∼4 GPa and a temperature of 873 ± 10 K. Temperature-dependent powder and single-crystal X-ray diffraction (XRD) analyses partly using synchrotron radiation as well as Raman spectroscopic investigations reveal a phase transition around 445 K resulting in the Cmcm high-temperature structure. The transformation temperature is considerably higher than that of lawsonite around 273 K, which is characterized predominantly by proton order/disorder. The transition is confirmed using principal component analysis and subsequent hierarchical cluster analysis on both the powder XRD patterns and the Raman spectra. Furthermore, a non-uniform change is observed around 355 K, which is not as pronounced as the 445 K transition and apparently comes from enhanced hydrogen bonding, which stops the atom shifts in Pb-lawsonite. These are the same bonds that mainly characterize the phase transition in lawsonite around 273 K. In contrast, the structural transition of Pblawsonite at 445 K seems to originate from the interaction of the SiO4 tetrahedra and AlO6 octahedra framework with the Pb2+ cation. The structural environment of Pb2+ can be described by a 12-fold coordination above 445 K, which changes towards irregular ten-fold coordination below this temperature. An assignment of the O–H stretching Raman bands confirms moderately strong H bonds in Pb-lawsonite, whereas both strong and weak H bonds exist in lawsonite. Therefore, a further phase transition of Pblawsonite, similar to that of lawsonite around 273 K, is not expected.

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Synthesis, X-ray diffraction and vibrational study of silicates and germanates isostructural with kentrolite Pb2Mn2Si2O9

Cited by 16 publications

References 4 publications

Polyanionic (Phosphates, Silicates, Sulfates) Frameworks as Electrode Materials for Rechargeable Li (or Na) Batteries

Polyanionic (Phosphates, Silicates, Sulfates) Frameworks as Electrode Materials for Rechargeable Li (or Na) Batteries

Pb₂Fe₂Ge₂O₉, the Germanate Analogue of the Silicate Mineral Melanotekite

T-induced displacive phase transition of end-member Pb-lawsonite

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Synthesis, X-ray diffraction and vibrational study of silicates and germanates isostructural with kentrolite Pb2Mn2Si2O9

Cited by 16 publications

References 4 publications

Polyanionic (Phosphates, Silicates, Sulfates) Frameworks as Electrode Materials for Rechargeable Li (or Na) Batteries

Polyanionic (Phosphates, Silicates, Sulfates) Frameworks as Electrode Materials for Rechargeable Li (or Na) Batteries

Pb2Fe2Ge2O9, the Germanate Analogue of the Silicate Mineral Melanotekite

T-induced displacive phase transition of end-member Pb-lawsonite

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Pb₂Fe₂Ge₂O₉, the Germanate Analogue of the Silicate Mineral Melanotekite