The new natural layered double hydroxide, Zn2Al(OH)6Cl·H2O, from the Lavrion ore District, Greece
- Authors: Zhitova E.S.1, Chukanov N.V.2, Pekov I.V.3, Schäfer C.4, Belakovskiy D.I.5, Van K.V.6, Zolotarev A.A.7
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Affiliations:
- Institute of Volcanology and Seismology Far East Branch RAS
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry RAS
- Moscow State University
- Gustav Stresemann-Strasse 34
- Fersman Mineralogical Museum RAS
- Korzhinskii Institute of Experimental Mineralogy RAS
- Saint Petersburg State University
- Issue: Vol CLIV, No 2 (2025)
- Pages: 75-87
- Section: NEW MINERALS
- URL: https://journals.rcsi.science/0869-6055/article/view/310873
- DOI: https://doi.org/10.31857/S0869605525020048
- EDN: https://elibrary.ru/HAMONF
- ID: 310873
Cite item
Abstract
The new natural Zn2Al-Cl layered double hydroxide (LDH) has been discovered among pro-ducts of the supergene alteration of sphalerite-rich ores at the Hilarion mine, Lavrion District, Attikí Prefecture, Greece. It forms intergrowth with wermlandite-like LDH and unidentified mineral phases. The chemical composition is (wt %, electron microprobe, H2O content is calculated by stoichiometry): ZnO 51.89, Al2O3 16.09, As2O5 1.83, Cl 10.08, H2O 22.87, –O=Cl2 –2.28, total 100.50. The empirical formula calculated on the basis of the sum of all metal atoms equal to 3 apfu is Zn2.01Al0.99(OH)5.94Cl0.90(AsO4)0.05×H2O. Associated minerals are aluminoceladonite (phengite), quartz, calcite, smithsonite, adamite, insufficiently studied LDHs, and goethite. The new natural Zn2Al-Cl LDH occurs as aggregates of split platy crystals up to 70 μm across and up to 10 μm thick. It has Mohs hardness about 2, mica-like cleavage on (001) and malleable tenacity. It is white with pearly lustre. The Zn2Al-Cl LDH crystallizes in space group R-3m, the unit-cell parameters are: a = 3.073(4), c = 23.14(3) Å, V = 189.1(6) Å3. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 7.71 (100) (003), 3.857 (52) (006), 2.594 (29) (012), 2.307 (40) (015), 1.9585 (11) (018). The calculated density is 2.78 g·cm–3. The natural Zn2Al-Cl LDH is optically uniaxial (+); w = 1.576(3), Nmax = 1.592(3). Chemically, the studied new natural LDH is a Zn-analogue of chlormagaluminite that explains similarities in their infrared spectra. The closest structural analogue is 3R polytype of iowaite that is also a chloride LDH, while chlormagaluminite is known as 2H polytype only.
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About the authors
E. S. Zhitova
Institute of Volcanology and Seismology Far East Branch RAS
Author for correspondence.
Email: zhitova_es@mail.ru
Russian Federation, Bulvar Piypa, 9, Petropavlovsk-Kamchatsky, 683006
N. V. Chukanov
Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry RAS
Email: zhitova_es@mail.ru
Russian Federation, Akad. Semenova 1, Chernogolovka, 142432
I. V. Pekov
Moscow State University
Email: zhitova_es@mail.ru
Russian Federation, Moscow, 119991
C. Schäfer
Gustav Stresemann-Strasse 34
Email: zhitova_es@mail.ru
Germany, Untereisesheim, 74257
D. I. Belakovskiy
Fersman Mineralogical Museum RAS
Email: zhitova_es@mail.ru
Russian Federation, Leninsky Prospekt 18-2, Moscow, 119071
K. V. Van
Korzhinskii Institute of Experimental Mineralogy RAS
Email: zhitova_es@mail.ru
Russian Federation, Chernogolovka, 142432
A. A. Zolotarev
Saint Petersburg State University
Email: zhitova_es@mail.ru
Russian Federation, University emb. 7/9, Saint Petersburg, 193004
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