Contribution to the crystallography of hydrotalcites: the crystal structures of woodallite and takovite

Mills, Stuart J.; Whitfield, Pamela S.; Kampf, Anthony R.; Wilson, Siobhan A.; Dipple, Gregory M.; Raudsepp, Mati; Favreau, Georges

doi:10.3190/jgeosci.127

Cited by 17 publications

(13 citation statements)

References 11 publications

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“…Thus, the presence of the reflection with d = 4.57 Å in the powder pattern of pure LDHs having M 2+ :M 3+ = 2:1 is a reliable indicator of cation ordering similar to the Li 2 Al LDHs [47][48][49][50]. In contrast to Cl-bearing hydrotalcite-supergroup members, the carbonate species have been structurally characterized in more details including recent single-crystal or Rietveld structure refinements of hydrotalcite [31], pyroaurite [51][52][53], quintinite [34,[53][54][55][56][57][58], takovite [59], and zaccagnaite [60]. It has been found that C atoms of CO 3 groups occupy central parts of the interlayer prisms (Figure 7b), whereas O atoms of CO 3 groups and H 2 O molecules are disordered around the middle points of the prism edges.…”

Section: Discussionmentioning

confidence: 99%

Crystal Chemistry of Chlormagaluminite, Mg4Al2(OH)12Cl2(H2O)2, a Natural Layered Double Hydroxide

et al. 2019

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Chlormagaluminite is the only Cl-dominated hydrotalcite-supergroup mineral species with M2+:M3+ = 2:1. The holotype sample of chlormagaluminite from the Kapaevskaya volcanic pipe (Irkutsk Oblast, Siberia, Russia) has been chemically and structurally characterized. The average chemical composition of the mineral is (electron microprobe, OH content is calculated by stoichiometry and H2O from the crystal-structure data, wt. %): MgO 33.85, FeO 1.09, Al2O3 22.07, Cl 14.72, H2Otot 30.96, Cl=O −3.39, total 99.30. The empirical formula based on Mg + Al + Fe = 6 atoms per formula unit (apfu) is [Mg3.91Fe2+0.07Al2.02(OH)12]Cl2.02(H2O)2.0(2). The crystal structure has been solved from single-crystal X-ray diffraction data in the space group P63/mcm, a = 5.268(3), c = 15.297(8) Å and V = 367.6(4) Å3. The refinement converged to R1 = 0.083 on the basis of 152 unique reﬂections with I > 2σ(I) collected at room conditions. The powder pattern contains standard reflections of a 2H polytype and two additional reflections [(010), d010 = 4.574 Å; (110), d110 = 2.647 Å] indicative of Mg and Al ordering according to the superstructure. The structure is based upon brucite-type octahedral layers with an ordered distribution of Mg and Al over octahedral sites. The Cl− anions and H2O molecules reside in the interlayer, providing a three-dimensional integrity of the structure.

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Section: Discussionmentioning

confidence: 99%

Crystal Chemistry of Chlormagaluminite, Mg4Al2(OH)12Cl2(H2O)2, a Natural Layered Double Hydroxide

et al. 2019

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“…Faultless crystalline -Ni(OH) 2 can be obtained by precipitation from very diluted salt solutions, and the synthesis procedure includes several ageing and washing steps (Palmer & Gamsjä ger, 2010 Graphical result of a Rietveld refinement of the diffraction pattern of the NCA-precursor material sample L002 using a faultless brucite-type structure model. This was observed in the crystal structure of takovite [Ni 1.869 Al 1.131 -(OH) 6 (CO 3 ) 1.020 ; Mills et al, 2013] A microstructural model was created that includes C19-, C6-and 3R-type stacking and the intercalation of carbonate or water. Selected reflection indices and the positions of the related lattice planes in the crystal structure (top) are given.…”

Section: Derivation Of Microstructural Features In the Ncaprecursor Mmentioning

confidence: 99%

“…In the case of an intercalation of water and/or carbonate, the intercalation layers do not necessarily have to be fully occupied, as partial occupation of intercalated molecules or ions was found in the structures of iowaite (Allmann & Donnay, 1969), takovite (Mills et al, 2013) and hydrotalcite (Allmann & Jepsen, 1969). Hence the total occupancy of the intercalation layers was optimized in an additional onedimensional grid search at the global minimum of the microstructure parameters (P x = 0.15, P y = 0.06 and P car = 0.07).…”

Section: Figurementioning

confidence: 99%

A routine for the determination of the microstructure of stacking-faulted nickel cobalt aluminium hydroxide precursors for lithium nickel cobalt aluminium oxide battery materials

Bette

Hinrichsen

Pfister³

et al. 2020

J Appl Cryst

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The microstructures of six stacking-faulted industrially produced cobalt- and aluminium-bearing nickel layered double hydroxide (LDH) samples that are used as precursors for Li(Ni1−x−yCo x Al y )O2 battery materials were investigated. Shifts from the brucite-type (AγB)□(AγB)□ stacking pattern to the CdCl2-type (AγB)□(CβA)□(BαC)□ and the CrOOH-type (BγA)□(AβC)□(CαB)□ stacking order, as well as random intercalation of water molecules and carbonate ions, were found to be the main features of the microstructures. A recursive routine for generating and averaging supercells of stacking-faulted layered substances implemented in the TOPAS software was used to calculate diffraction patterns of the LDH phases as a function of the degree of faulting and to refine them against the measured diffraction data. The microstructures of the precursor materials were described by a model containing three parameters: transition probabilities for generating CdCl2-type and CrOOH-type faults and a transition probability for the random intercalation of water/carbonate layers. Automated series of simulations and refinements were performed, in which the transition probabilities were modified incrementally and thus the microstructures optimized by a grid search. All samples were found to exhibit the same fraction of CdCl2-type and CrOOH-type stacking faults, which indicates that they have identical Ni, Co and Al contents. Different degrees of interstratification faulting were determined, which could be correlated to different heights of intercalation-water-related mass-loss steps in the thermal analyses.

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“…The arrangement of Cl − anions and H 2 O groups in the interlayer space of dritsite shows statistical disorder ( Figure 5). The general architecture of the interlayer arrangement of dritsite is principally different from that of carbonate hydrotalcite supergroup minerals, namely quintinite, hydrotalcite, pyroaurite, stichtite, takovite, and zaccagnaite [38,[43][44][45][46][47][48][49][50], as shown in Figure 5c,d. In accordance with the approach by Bookin and Drits [23], the interlayer space can be considered as consisting of trigonal prisms formed by H atoms occupying the H1 site of the metal-hydroxide layers (Figure 5e,f).…”

Section: Crystal Structure Of Dritsite-2hmentioning

confidence: 99%

Dritsite, Li2Al4(OH)12Cl2·3H2O, a New Gibbsite-Based Hydrotalcite Supergroup Mineral

et al. 2019

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Dritsite, ideally Li2Al4(OH)12Cl2·3H2O, is a new hydrotalcite supergroup mineral formed as a result of diagenesis in the halite−carnallite rock of the Verkhnekamskoe salt deposit, Perm Krai, Russia. Dritsite forms single lamellar or tabular hexagonal crystals up to 0.25 mm across. The mineral is transparent and colourless, with perfect cleavage on {001}. The chemical composition of dritsite (wt. %; by combination of electron microprobe and ICP−MS; H2O calculated by structure refinement) is: Li2O 6.6, Al2O3 45.42, SiO2 0.11, Cl 14.33, SO3 0.21, H2Ocalc. 34.86, O = Cl − 3.24, total 98.29. The empirical formula based on Li + Al + Si = 6 apfu (atom per formula unit) is Li1.99Al4.00Si0.01[(OH)12.19Cl1.82(SO4)0.01]Σ14.02·2.60(H2O). The Raman spectroscopic data indicate the presence of O–H bonding in the mineral, whereas CO32– groups are absent. The crystal structure has been refined in the space group P63/mcm, a = 5.0960(3), c = 15.3578(13) Å, and V = 345.4(5) Å3, to R1 = 0.088 using single-crystal data. The strongest lines of the powder X-ray diffraction pattern (d, Å (I, %) (hkl)) are: 7.68 (100) (002), 4.422 (61) (010), 3.832 (99) (004, 012), 2.561 (30) (006), 2.283 (25) (113), and 1.445 (26) (032). Dritsite was found as 2H polytype, which is isotypic with synthetic material and shows strong similarity to chlormagalumite-2H. The mineral is named in honour of the Russian crystallographer and mineralogist Prof. Victor Anatol`evich Drits.

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Contribution to the crystallography of hydrotalcites: the crystal structures of woodallite and takovite

Abstract: The crystal structures of the 3R polytypes of takovite and woodallite are presented. The structure of takovite was solved on a single crystal from the Agoudal mine, Bou Azzer district, Tazenakht, Morocco to R 1 = 1.87 % for 94 unique reflec-

Cited by 17 publications

References 11 publications

Crystal Chemistry of Chlormagaluminite, Mg4Al2(OH)12Cl2(H2O)2, a Natural Layered Double Hydroxide

Crystal Chemistry of Chlormagaluminite, Mg4Al2(OH)12Cl2(H2O)2, a Natural Layered Double Hydroxide

A routine for the determination of the microstructure of stacking-faulted nickel cobalt aluminium hydroxide precursors for lithium nickel cobalt aluminium oxide battery materials

Dritsite, Li2Al4(OH)12Cl2·3H2O, a New Gibbsite-Based Hydrotalcite Supergroup Mineral

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