Syntheses and Crystal Structures of Four New Ammoniates with Heptaarsenide (As$\rm{_{7}^{3-}}$) Anions

Abstract

The syntheses and X-ray single-crystal low-temperature structures of the four new ammoniates [Li(NH 3 ) 4 ] 3 As 7´N H 3 (1), ] 3 As 7´8 NH 3 (2), Cs 3 As 7´6 NH 3 (3), and (Ph 4 P) 2 CsAs 7´5 NH 3 (4) are reported. The compounds were obtained by either direct reduction of As with Li/Cs in liquid NH 3 , solvation of Cs 4 As 6 /Rb 4 As 6 in liquid NH 3 , or by extraction of solid Cs 3 As 7 . While compound 1 contains isolated As 3À 7 polyanions, AsÀM contacts (M Na À Cs) lead to neutral 2À chains in 4, respectively.

Chemical Bond in the Cyclic Anions P64− and As64−: Synthesis, Crystal Structure, and Electron Localization Function of {Rb[18]crown‐6)}2Rb2As6⋅6 NH3

“…[2,9] Arsenic, the heavier congener of phosphorus, forms the compounds M 4 As 6 (M = Rb, Cs), [12] which are isotypic to the hexaphosphides. Upon solvation in liquid ammonia, these hexaarsenides form heptaarsenide As 7 3À , [13] tetradecaarsenide [(As 7 ) 2 ] 4À , [14] and the lone pair aromatic cyclotetraarsenide As 4 2À as crystalline products. [15,16] However, in contrast to the hexaphosphide anion, the hexaarsenide anion seems to be moderately stable in liquid ammonia solutions, and we have now been able to dissolve Rb 4 As 6 congruently in it.…”

The Chemical Bond in Polyphosphides: Crystal Structures, the Electron Localization Function, and a New View of Aromaticity in P42− and P5−

“…In ionic Pn 7 3À cages (Pn = P, As, Sb), the angle g is found to be smaller than the angle d; the reverse is true for covalent species. [68,69] For the designation scheme used, see Figure 11. The Q ratios are very similar, with values around 1.31 (Table 2).…”

Zintl‐Ionen, Käfigverbindungen und intermetalloide Cluster der Elemente der 14. und 15. Gruppe

“…Wie die neunatomigen Cluster [E 9 ] 4− im Fall der Tetrelelemente sind für Pn=P, As und Sb die Heptapnikanortricyclan‐Anionen [Pn 7 ] 3− die am häufigsten in Lösung gefundenen Spezies (Abbildung 1 k). 42, 107, 111–116, 129–132 In [K 17 (Sb 8 ) 2 (NH 2 )](NH 3 ) 17.5 (Abbildung 1 i)136 liegt eine S 8 ‐analoge kronenförmige [Sb 8 ] 8− ‐Einheit vor, und – wie den Tabellen 2 und 7 (siehe Anhang) zu entnehmen ist – sind auch die Trishomocuban(Ufosan)‐förmigen Anionen [Pn 11 ] 3− (Pn=P, As und Sb) unter den Polypniktiden weit verbreitet (Abbildung 1 l). 113, 117–121, 133, 134, 137…”