Hidden and apparent twins in uranyl-oxide minerals agrinierite and rameauite: a demonstration of metric and reticular merohedry

0558445 - FZÚ 2023 RIV GB eng J - Journal Article
Plášil, Jakub - Petříček, Václav - Škoda, R. - Meisser, N. - Kasatkin, A.V.
Hidden and apparent twins in uranyl-oxide minerals agrinierite and rameauite: a demonstration of metric and reticular merohedry.
Journal of Applied Crystallography. Roč. 54, č. 6 (2021), s. 1656-1663. ISSN 0021-8898. E-ISSN 1600-5767
R&D Projects: GA ČR(CZ) GA20-11949S
Institutional support: RVO:68378271
Keywords : agrinierite * rameauite * twinning * merohedry * Jana2020
OECD category: Mineralogy
Impact factor: 4.868, year: 2021
Method of publishing: Open access

In this work, the structures of chemically related uranyl-oxide minerals agrinierite and rameauite have been revisited and some corrections to the available structure data are provided. Both structures were found to be twinned. The two minerals are chemically similar, and though their structures differ considerably, their unit-cell metrics are similar. Agrinierite was found to be twinned by metric merohedry (diffraction type I), whereas the structure of rameauite is twinned by reticular merohedry (diffraction type II). The twinning of the monoclinic unit cells (true cells) leads to pseudo-orthorh ombic or pseudotetragonal supercells in the single-crystal diffraction patterns of both minerals.
Permanent Link: http://hdl.handle.net/11104/0332088