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12Cl23h2o, a New Gibbsite-Based Hydrotalcite Supergroup

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12Cl23h2o, a New Gibbsite-Based Hydrotalcite Supergroup minerals Article Dritsite, Li2Al4(OH)12Cl2·3H2O, a New Gibbsite-Based Hydrotalcite Supergroup Mineral Elena S. Zhitova 1,2,* , Igor V. Pekov 3, Ilya I. Chaikovskiy 4, Elena P. Chirkova 4, Vasiliy O. Yapaskurt 3, Yana V. Bychkova 3, Dmitry I. Belakovskiy 5, Nikita V. Chukanov 6, Natalia V. Zubkova 3, Sergey V. Krivovichev 1,7 and Vladimir N. Bocharov 8 1 Department of Crystallography, St. Petersburg State University, Universitetskaya nab. 7/9, St. Petersburg 199034, Russia 2 Laboratory of Mineralogy, Institute of Volcanology and Seismology, Russian Academy of Sciences, Bulvar Piypa 9, Petropavlovsk-Kamchatsky 683006, Russia 3 Faculty of Geology, Moscow State University, Vorobievy Gory, Moscow 119991, Russia 4 Mining Institute, Ural Branch of the Russian Academy of Sciences, Sibirskaya str., 78a, Perm 614007, Russia 5 Fersman Mineralogical Museum, Russian Academy of Sciences, Leninsky Prospekt 18-2, Moscow 119071, Russia 6 Institute of Problems of Chemical Physics, Russian Academy of Sciences, Akad. Semenova 1, Chernogolovka, Moscow Region 142432, Russia 7 Nanomaterials Research Centre, Kola Science Centre, Russian Academy of Sciences, Fersman Street 14, Apatity 184209, Russia 8 Resource Center Geomodel, St. Petersburg State University, Universitetskaya nab. 7/9, St. Petersburg 199034, Russia * Correspondence: [email protected]; Tel.: +7-924-587-51-91 Received: 2 August 2019; Accepted: 14 August 2019; Published: 17 August 2019 Abstract: Dritsite, ideally Li Al (OH) Cl 3H O, is a new hydrotalcite supergroup mineral formed 2 4 12 2· 2 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; H O calculated by structure − 2 refinement) is: Li O 6.6, Al O 45.42, SiO 0.11, Cl 14.33, SO 0.21, H O 34.86, O = Cl 3.24, 2 2 3 2 3 2 calc. − 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]S14.02 2.60(H2O). The Raman spectroscopic data indicate the · 2– presence of O–H bonding in the mineral, whereas CO3 groups are absent. The crystal structure 3 has been refined in the space group P63/mcm, a = 5.0960(3), c = 15.3578(13) Å, and V = 345.4(5) Å , 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. Keywords: dritsite; hydrotalcite supergroup; lithium aluminium hydroxide; layered double hydroxide; gibbsite-derived; crystal structure; evaporitic salt rock; Verkhnekamskoe potassium salt deposit; Perm Krai 1. Introduction In this paper we provide a description of the new hydrotalcite supergroup mineral dritsite. Hydrotalcite supergroup minerals are commonly known as layered double hydroxides (LDHs), i.e., Minerals 2019, 9, 492; doi:10.3390/min9080492 www.mdpi.com/journal/minerals MineralsMinerals 20192019,, 99,, x 492 FOR PEER REVIEW 2 2of of 15 15 LiAl2-based LDHs is also known [4–19]. Currently, forty-four hydrotalcite supergroup minerals are knownhydroxides, including containing some two that cations, are questionable usually di- andas mineral trivalent species [1–3], although[3]. All aof group them, of excluding synthetic LiAl -based LDHs is also known [4–19]. Currently, forty-four hydrotalcite supergroup minerals are mössbauerite2 , are composed of di- and trivalent cations, whereas mössbauerite contains only Fe3+ [known,20]. The including new somemonoclinic that are questionablemineral akopovaite as mineral, speciesrecently [ 3].approved All of them, by excluding the IMA mössbauerite,−CNMNC 3+ (areInternational composed ofMineralogical di- and trivalent Association cations,, whereasCommission mössbauerite on new contains minerals, only nomenclature Fe [20]. The newand monoclinic mineral akopovaite, recently approved by the IMA CNMNC (International Mineralogical classification) (IMA2018-095, [21]), has the chemical formula Li−2Al4(OH)12CO3·3H2O, however, its full descriptionAssociation, has Commission not yet been on new published. minerals, Th nomenclatureus, here we andprovid classification)e the first (IMA2018-095,description of [this21]), natural has the chemical formula Li2Al4(OH)12CO3 3H2O, however, its full description has not yet been published. LiAl2-based LDH. The crystal structures· of all currently known hydrotalcite supergroup members areThus, based here on we brucite provide-type the layers first description (Figure 1) of, where this natural some LiAlof M22+-based cations LDH. are Thereplaced crystal by structures M3+. A strong of all predominancecurrently known of hydrotalciteM2+ cations over supergroup M3+ is observed members, arewith based the most on brucite-type common M layers2+:M3+ (Figure ratios 1being), where 2:1 some of M2+ cations are replaced by M3+. A strong predominance of M2+ cations over M3+ is observed, and 3:1. The crystal structures of LiAl2-LDHs are based upon gibbsite-derived dioctahedral layers of with the most common M2+:M3+ ratios being 2:1 and 3:1. The crystal structures of LiAl -LDHs are Al(OH)6 octahedra, with vacant octahedral sites occupied by Li+ cations (Figure 1). The [LiAl2 2(OH)6]+ octahedralbased upon layers gibbsite-derived alternate, with dioctahedral negatively layers charged of Al(OH) interlayer6 octahedra, constituents with represented vacant octahedral by anions sites occupied by Li+ cations (Figure1). The [LiAl (OH) ]+ octahedral layers alternate, with negatively Cl−, CO32−, SO42−, and H2O groups. 2 6 2 2 chargedThe interlayernew mineral constituents is named represented in honour of by the anions Russian Cl−, crystallographer CO3 −, SO4 −, and and H 2mineralogistO groups. Victor Anatol`evichThe new Drits mineral (Виктор is named Анатольевич in honour ofДриц the Russian) (born crystallographer1932) from Geological and mineralogist Institute of Victor the иктор н тольевич Дриц RussianAnatol‘evich Academy Drits of (B SciencesA, Moscow,a Russia. )Prof. (born Drits 1932) is froman outstanding Geological sp Instituteecialist in of mineralogy the Russian ofAcademy sedimentary of Sciences, rocks and Moscow, crystal Russia.chemistry Prof. of compounds Drits is an outstandingwith layered specialist structures, in especially mineralogy clay of mineralssedimentary. He contributed rocks andcrystal greatlychemistry to the development of compounds of new with scientific layered methods structures, and approaches especiallyclay for theminerals. studies He of contributed crystal chemistry greatly to theand development systematics ofof new layered scientific minerals methods, including and approaches hydrotalcite for the supergroupstudies of crystal members chemistry [22,23] and. The systematics mineral and of layeredits name minerals, have been including approved hydrotalcite by the IMA supergroup-CNMNC (IMA2019members- [017)22,23. ]. The mineral and its name have been approved by the IMA-CNMNC (IMA2019-017). TThehe t typeype material material is is deposited in in the collections of the Fersman Mineralogical Museum Museum of of the the RussianRussian Academy Academy of of Sciences Sciences,, Moscow, Russia,Russia, under the registration registration number number 5380/1. 5380/1. FigureFigure 1. ((aa)) The The dioctahedral dioctahedral layer layer in in the the crystal crystal structure of gibbsite [2 [244] composed of Al(OH)6 octahedraoctahedra and and containing containing vacancies vacancies.. ( (bb)) T Thehe trioctahedral trioctahedral layer layer in in the the crystal crystal structure structure of of brucite brucite [2 [255]] composedcomposed of of Mg(OH) Mg(OH)66 octahedraoctahedra as as a a main main structural structural unit unit of of LDHs LDHs composed composed of of di di-- and and trivalent cationscations (all (all currently currently known known hydrotalcite supergroup members). 2.2. Materials Materials and and Methods Methods 2.1. Occurrence, Appearance, Physical Properties, and Optical Data 2.1. Occurrence, Appearance, Physical Properties, and Optical Data Dritsite was found in the core of the borehole #2001, at a depth of 247.6–248 m, drilled at the Dritsite was found in the core of the borehole #2001, at a depth of 247.6–248 m, drilled at the Romanovskiy area of the well-known giant Verkhnekamskoe potassium salt deposit, 30-km south Romanovskiy area of the well-known giant Verkhnekamskoe potassium salt deposit, 30-km south of of the city of Berezniki, Perm Krai, Western Urals, Russia [26–28]. The new mineral was found in a the city of Berezniki, Perm Krai, Western Urals, Russia [26–28]. The new mineral was found in a halite carnallite rock in association with dolomite, magnesite, quartz, Sr-bearing baryte, kaolinite, halite−−carnallite rock in association with dolomite, magnesite, quartz, Sr-bearing baryte, kaolinite, potassic feldspar, krasnoshteinite, Al8[B2O4(OH)2](OH)16Cl4 7H2O (IMA2018-077) [29], congolite, potassic feldspar, krasnoshteinite, Al8[B2O4(OH)2](OH)16Cl47·H2O (IMA2018-077) [29], congolite, members of the goyazite–woodhouseite series, fluorite, hematite,
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