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Probing the Zintl–Klemm Concept: A Combined Experimental and Theoretical Charge Density Study of the Zintl Phase CaSi
Author(s) -
Kurylyshyn Iryna M.,
Fässler Thomas F.,
Fischer Andreas,
Hauf Christoph,
Eickerling Georg,
Presnitz Manuel,
Scherer Wolfgang
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201308888
Subject(s) - ionic bonding , covalent bond , charge (physics) , chemical bond , character (mathematics) , chemical physics , zintl phase , chemistry , charge density , ion , phase (matter) , ionic potential , characterization (materials science) , crystallography , computational chemistry , materials science , nanotechnology , physics , crystal structure , quantum mechanics , geometry , mathematics , organic chemistry
The nature of the chemical bonds in CaSi, a textbook example of a Zintl phase, was investigated for the first time by means of a combined experimental and theoretical charge density analysis to test the validity of the Zintl–Klemm concept. The presence of covalent SiSi interactions, which were shown by QTAIM analysis, supports this fundamental bonding concept. However, the use of an experimental charge density study and theoretical band structure analyses give clear evidence that the cation–anion interaction cannot be described as purely ionic, but also has partially covalent character. Integrated QTAIM atomic charges of the atoms contradict the original Zintl–Klemm concept and deliver a possible explanation for the unexpected metallic behavior of CaSi.