Caesium in high oxidation states and as a p-block element.
Nat Chem 2013;
5:846-52. [PMID:
24056341 DOI:
10.1038/nchem.1754]
[Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 08/09/2013] [Indexed: 11/08/2022]
Abstract
The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry, rooted in the atomic shell structure. Within compounds, Group I elements, for example, invariably assume the +1 oxidation state, and their chemical properties differ completely from those of the p-block elements. These general rules govern our understanding of chemical structures and reactions. Here, first-principles calculations show that, under pressure, caesium atoms can share their 5p electrons to become formally oxidized beyond the +1 state. In the presence of fluorine and under pressure, the formation of CsF(n) (n > 1) compounds containing neutral or ionic molecules is predicted. Their geometry and bonding resemble that of isoelectronic XeF(n) molecules, showing a caesium atom that behaves chemically like a p-block element under these conditions. The calculated stability of the CsF(n) compounds shows that the inner-shell electrons can become the main components of chemical bonds.
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