Recent advances in the understanding of the syntheses, structures, bonding and energetics of the homopolyatomic cations of Groups 16 and 17

Isolation and reversible dimerization of a selenium–selenium three-electron σ-bond

“…This is due to the strong electrostatic repulsion of the two adjacent positive charges in À assuming ionic radii are similar, as shown by the Kapustiniskii equation (Fig. 6a) 41,[59][60][61] , where z x and z y are the charge of the ions, r x and r y the ionic radii and n is the number of ions per formula unit (for example, two for X þ Y À and three for X 2 þ (Y À ) 2 ). As shown in the Born-Fajans-Haber cycle (Fig.…”

Ein Iridium‐stabilisiertes, formal neutrales Te10‐Molekül mit Drei‐Zentren‐vier‐Elektronen‐Bindung

“…Ã [10] oder in ausgedehnten Strukturen wie b-TeI [11] À diskutiert wird. [13] Ein Bindungslänge-Bindungsstärke-Vergleich für das lineare Te 3 -Fragment ergibt Bindungsvalenzen von 0.62 und 0.43.…”

Ligand‐Stabilized Chalcogen Dications

“…In this context, it is noteworthy that treatment of elemental chalcogens with very strong oxidizing agents produces a variety of homocyclic chalcogen dications, for example, E 4 2+ (E = S, Se), E 8 2+ (E = S, Se), and Se 10 2+ ; however the highest formal oxidation state of the chalcogen is + 0.5. [14] Other examples of structurally characterized dicationic sulfur or selenium species include a) a stable salt of an organosulfur(IV) dication [15] and b) the tetracoordinated species [S(NPMe 3 ) 4 ] 2+ , which is described as a dication of hexavalent sulfur. [16] The results of a comprehensive study by Tuononen et al of the electronic structures of p-block element analogues of NHCs reinforce the conclusions derived from structural data.…”