English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The structure of hydrated calcium uranyl carbonate, mineral sharpite, has been solved for the first time. The structure is orthorhombic, space group  Cmcm , with the unit-cell parameters  a =4.9032 (4),  b =15.6489 (11),  c =22.0414 (18) Å,  V =1691.2 (2) Å 3 ,  Z =4. The structure was refined from 858 unique observed reflections to a final  R =5.48% (GOF=1.48). The structure is based upon infinite Ca 2+ -uranyl-carbonate sheets, which are unique among uranyl minerals and inorganic compounds. They result from edge-sharing of triangles, occupied by CO 3 , and hexagons that are occupied both by UO 8  and Ca 2+ (H 2 O) 3 O 5 . Thus, topology of the sheets is identical to rutherfordine, (UO 2 )(CO 3 ). Nevertheless Ca 2+  is occupying one of the hexagons of the topology in sharpite. Sheets are extremely corrugated, stacked perpendicular to  b  and linked by H-bonds and Van Der Waals interactions, only. The ideal chemical formula of sharpite is {Ca(H 2  [3] O) 3 [(UO 2 ) 3 (CO 3 ) 3.6 O 0.2 ]} 0 ,  Z =4; however, one of the C sites was found to be only partially occupied. The character of sharpite structure is probably a key to understand its scarcity of occurrences in Nature.

A unique structure of uranyl-carbonate mineral sharpite: a derivative of the rutherfordine topology