Ionic Ozonides

Abstract

Ionic Ozonides [1] were mentioned for the first time during the second half of the nineteenth century. However, fundamental aspects of their chemistry and physics remained obscure until more recently procedures had been provided that allow for their syntheses in gram‐amounts, and in high purity. Respective preparative approaches start by reacting the alkali metal superoxides KO2, RbO2, or CsO2 with O2/O3 mixtures, at punctilious temperature control. Subsequently, the raw product is extracted with liquid ammonia. From the solution obtained, solid ozonides are harvested and purified by recrystallization. As rather versatile and efficient accesses to ozonides of further cations, metathesis reactions or cation exchange in liquid ammonia have been developed. The samples obtained have allowed for full structural and basic physical characterizations. All ionic ozonides known are metastable with respect to release of dioxygen, [NMe4]O3 being the most stable one (onset of rapid decomposition at 348 K). Depending on the respective crystal field, the bond lengths and angles of the ozonide anion vary significantly, and consistently, from 135 to 129 pm, and 113 to 120°, respectively. The magnetic moments of the paramagnetic O3− determined by susceptibility measurements (1.70–1.80 μB) deviate but slightly from the spin‐only value for one unpaired electron. This finding complies well with the small anisotropy of the g‐factors. As an achievement of possibly far reaching consequences, stable solutions of ionic ozonides in organic solvents have become available, opening the way to the use of O3− as a ligand, or synthon, in coordination and molecular chemistry.

Challenge of Magnetism in Strongly Correlated Open-Shell2pSystems

“…The alkali-metal atoms transfer their electrons to the oxygen molecules resulting in ionic crystals with dioxygen anions that retain the molecular properties of solid oxygen [5]. In particular, the heavy alkali metals form compounds with oxidation states that range from metallic suboxides [6] to the ozonides [7]. In this Letter it will be shown that the alkali sesquioxides-Rb 4 O 6 and Cs 4 O 6 -are of principal importance.…”

α‐RbO3, a Low Temperature Polymorph of Rubidium Ozonide

“…According to the procedure mentioned in the introduction, RbO 2 (approx. 100 mg) was placed on a glass frit in a dedicated vessel, fitted with a cooling jacket as described in the literature , . A continuous flow of O 2 /O 3 , generated by a commercial ozonizer, was conveyed through the finely ground sample.…”

“…However, the true nature of the at that time not isolable substance remained obscure for more than hundred years until in the eighties of the past century reproducible and versatile procedures for synthesis of this family of capricious compounds as single phase, coarse crystalline materials and in gram amounts had been developed . Their true constitutions as ionic ozonides, containing the radical anion (O 3 ) – , have been unambiguously revealed by single crystal structure determinations , . The only synthetic access to ionic ozonides known proceeds by reacting alkali metal superoxides KO 2 , RbO 2 , or CsO 2 with gaseous mixtures of dioxygen and ozone (as produced by a Siemens ozonizer), followed by extraction of the raw product with liquid ammonia.…”

Single Crystals of CaNa[ReO4]3: Serendipitous Formation and Systematic Characterization

“…The scientific oeuvre of Martin Jansen has a strong pronunciation on solid‐state oxides, which covers binary alkali‐metal oxides with strange oxidation states at the oxygen atoms (e.g. ozonides A O 3 ( A = Na – Cs), or sesquioxides A 2 O 3 ( A = K – Cs)) as well as oxometalates with transition metals in their highest possible oxidation states (e.g. Ag[MnO 4 ] or Hg 4 O 3 [ReO 4 ] 2 for members of group VII).…”