Znucalite, the only known zinc uranyl carbonate: Its crystal structure and environmental implications

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00023272%3A_____%2F24%3A10136680" target="_blank" >RIV/00023272:_____/24:10136680 - isvavai.cz</a>

Alternative codes found

RIV/68378271:_____/24:00585800 RIV/00216224:14310/24:00138750

Result on the web

<a href="https://pubs.geoscienceworld.org/msa/ammin/article-abstract/109/5/949/638828/Znucalite-the-only-known-zinc-uranyl-carbonate-Its?redirectedFrom=fulltext" target="_blank" >https://pubs.geoscienceworld.org/msa/ammin/article-abstract/109/5/949/638828/Znucalite-the-only-known-zinc-uranyl-carbonate-Its?redirectedFrom=fulltext</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.2138/am-2023-8956" target="_blank" >10.2138/am-2023-8956</a>

Result language

angličtina

Original language name

Znucalite, the only known zinc uranyl carbonate: Its crystal structure and environmental implications

Original language description

Znucalite is a zinc uranyl-carbonate mineral that was until recently only partially characterized with a formula originally given as Zn12Ca(UO2)(CO3)(3)(OH)(22)4H(2)O, with an unknown crystal structure and ambiguous symmetry determinations. We have reinvestigated this mineral using three-dimensional electron diffraction (3D ED) and powder X-ray diffraction and revealed for the first time its structural details. Znucalite is unambiguously monoclinic, P21/m, with a = 10.722(2) Å;, b = 6.259(1) Å;, c = 25.355(1) Å;, beta = 101.13(1)degrees, and V = 1669.54(9) Å3. The structure refinement of the 3D ED data using the dynamical approach (Robs = 0.1594 for 3579 observed reflections and 244 parameters) provided the following structure model. Znucalite possesses a layered structure, with a [Zn10(OH)14(CO3)2] double sheet (with Zn2+ both in octahedra and tetrahedra), which is connected to a thick interlayer that hosts U6+, Ca2+, and H2O molecules. The linkage between structural units and the interlayer occurs via the vertices of ZnO4 tetrahedra protruding from the sheet. In the interlayer, differences in ordering between U and Ca take place and likely cause the difficulties encountered during the attempts to solve the structure. The refined structural formula of znucalite, Zn10Ca0.828[UO2]0.828[CO3]4(OH)15.312(H2O)5.484, corresponds well to the composition obtained from the electron-microprobe analyses, (Zn9.84Al0.16)Σ10.00 Ca0.83(UO2)0.80[(CO3)3.96(SO4)0.04]Σ4.00(OH)15.42(H2O)5.48. Raman spectroscopy evidenced the presence of several non-equivalent CO3 groups, as well as OH and H2O. The U-O bond lengths obtained from the stretching frequencies of UO22+ vibrations are in line with the structural model. A discussion on the environmental importance of znucalite is appended, based on geochemical calculations with an estimate of the solubility product for this mineral.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10504 - Mineralogy

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

American Mineralogist

ISSN

0003-004X

e-ISSN

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Volume of the periodical

109

Issue of the periodical within the volume

5

Country of publishing house

US - UNITED STATES

Number of pages

11

Pages from-to

949-959

UT code for WoS article

001245532900010

EID of the result in the Scopus database

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