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Crystal chemistry of natural layered double hydroxides. 5. Single-crystal structure refinement of hydrotalcite, [Mg6Al2(OH)16](CO3)(H2O)4

Zhitova, E.S.; Krivovichev, S.V.; Pekov, I.V.; Greenwell, H.C.

Crystal chemistry of natural layered double hydroxides. 5. Single-crystal structure refinement of hydrotalcite, [Mg6Al2(OH)16](CO3)(H2O)4 Thumbnail


Authors

E.S. Zhitova

S.V. Krivovichev

I.V. Pekov



Abstract

Hydrotalcite, ideally [Mg6Al2(OH)16](CO3)(H2O)4, was studied in samples from Dypingdal, Snarum, Norway (3R and 2H), Zelentsovskaya pit (2H) and Praskovie–Evgenievskaya pit (2H) (both Southern Urals, Russia), Talnakh, Siberia, Russia (3R), Khibiny, Kola, Russia (3R), and St. Lawrence, New York, USA (3R and 2H). Two polytypes, 3R and 2H (both ‘classical’), were confirmed on the basis of single-crystal and powder X-ray diffraction data. Their chemical composition was studied by electron-microprobe analysis, infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The crystal structure of hydrotalcite-3R was solved by direct methods in the space group R3m on three crystals (two data collections at 290 K and one at 120 K). The unit-cell parameters are as follows (290/290/120 K): a = 3.0728(9)/3.0626(3)/3.0617(4), c = 23.326(9)/23.313(3)/23.203(3) Å and V = 190.7(1)/189.37(4)/188.36(4) Å3 . The crystal structures were refined on the basis of 304/150/101 reflections to R1 = 0.075/0.041/ 0.038. Hydrotalcite-2H crystallises in the P63/mmc space group; unit-cell parameters for two crystals are (data collection at 290 K and 93 K): a = 3.046(1)/3.0521(9), c = 15.447(6)/15.439(4) Å, V = 124.39(8)/124.55(8) Å3 . The crystal structures were refined on the basis of 160/142 reflections to R1 = 0.077/0.059. This paper reports the first single-crystal structure data on hydrotalcite. Hydrotalcite distribution in Nature, diagnostic features, polytypism, interlayer topology and localisation of M2+–M3+ cations within metal hydroxide layers are discussed.

Citation

Zhitova, E., Krivovichev, S., Pekov, I., & Greenwell, H. (2019). Crystal chemistry of natural layered double hydroxides. 5. Single-crystal structure refinement of hydrotalcite, [Mg6Al2(OH)16](CO3)(H2O)4. Mineralogical Magazine, 83(2), 269-280. https://doi.org/10.1180/mgm.2018.145

Journal Article Type Article
Acceptance Date Jul 3, 2018
Online Publication Date Jul 25, 2018
Publication Date Apr 30, 2019
Deposit Date Aug 20, 2018
Publicly Available Date Mar 29, 2024
Journal Mineralogical Magazine
Print ISSN 0026-461X
Electronic ISSN 1471-8022
Publisher Mineralogical Society
Peer Reviewed Peer Reviewed
Volume 83
Issue 2
Pages 269-280
DOI https://doi.org/10.1180/mgm.2018.145

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