Structure and Bonding in Silver Halides. A Quantum Chemical Study of the Monomers:  Ag2X, AgX, AgX2, and AgX3 (X = F, Cl, Br, I)

• Published in: Journal of the American Chemical Society 2005-06, Vol.127 (22), p.8133-8145
• Main Authors: Müller-Rösing, Hans-Christian, Schulz, Axel, Hargittai, Magdolna
• Format: Article
• Language: English
• Subjects: Atomic and molecular physics; Calculations and mathematical techniques in atomic and molecular physics (excluding electron correlation calculations); Coupled cluster theory; Electronic structure of atoms, molecules and their ions: theory; Exact sciences and technology; Physics; Statistical model calculations (including Thomas-Fermi and Thomas-Fermi-Dirac models)
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja051442j

The molecular structure of all silver halide monomers, Ag2X, AgX, AgX2, and AgX3, (X = F, Cl, Br, I), have been calculated at the B3LYP, MP2, and CCSD(T) levels of theory by using quasirelativistic pseudopotentials for all atoms except fluorine and chlorine. All silver monohalides are stable molecules, while the relative stabilities of the subhalides, dihalides, and trihalides considerably decrease toward the larger halogens. The ground-state structure of all Ag2X silver subhalides has C 2 v symmetry, and the molecules can be best described as [Ag2]+X-. Silver dihalides are linear molecules; AgF2 has a 2Σg ground state, while all of the other silver dihalides have a ground state of 2Πg symmetry. The potential energy surface (PES) of all silver trihalides has been investigated. Neither of these molecules has a D 3 h symmetric trigonal planar geometry, due to their Jahn−Teller distortion. The minimum energy structure of AgF3 is a T-shaped structure with C 2 v symmetry. For AgCl3, AgBr3, and AgI3, the global minimum is an L-shaped structure, which lies outside the Jahn−Teller PES. This structure can be considered as a donor−acceptor system, with X2 acting as donor and AgX as acceptor. Thus, except for AgF3, in the other three silver trihalides, silver is not present in the formal oxidation state 3.