Hydroflux synthesis and crystal structure of Tl₃IO

Abstract

Single-crystals of thallium(I) iodide oxide Tl3IO were obtained as by-product in a hydroflux synthesis at 473 K for 10 h. A potassium hydroxide hydroflux with a water-base molar ratio of 1.6 and the starting materials TlNO3, RhI3 and Ba(NO3)2 was used, resulting in a few black needle-shaped crystals. X-ray diffraction on a single-crystal revealed the hexagonal space group P63/mmc (No. 194) with lattice parameters a = 7.1512 (3) Å and c = 6.3639 (3) Å. Tl3IO crystallizes as hexagonal anti-perovskite (anti-BaNiO3 type) and is thus structurally related to the alkali-metal halide/auride oxides M 3 XO (M = K, Rb, Cs; X = Cl, Br, I, Au). The oxygen atoms center thallium octahedra. The [OTl6] octahedra share trans faces, forming a linear chain along [001]. Twelve thallium atoms surround each iodine atom in an [ITl12] anti-cuboctahedron. Thallium and iodine atoms together form a hexagonal close-sphere packing, in which every fourth octahedral void is occupied by oxygen.

Chalcogenides by Reduction of their Dioxides in Ultra‐Alkaline Media

“…Washing of the reaction product with a protic solvent, for example, an alcohol, strongly increases the activity of water and thereby induces the decomposition of K 2 Ch 3 . Similar observations had been made for other water sensitive products from hydroflux syntheses, for example, K 2 [Fe 2 O 3 (OH) 2 ] or Tl 3 IO [27, 28] . Also several aprotic polar solvents, for example, DMF, proved to be unsuitable for rinsing because potassium hydroxide is less soluble in them than the trichalcogenides.…”

“…Similar observations had been made for other water sensitive products from hydroflux syntheses, for example, K 2 [Fe 2 O 3 (OH) 2 ] or Tl 3 IO. [ 27 , 28 ] Also several aprotic polar solvents, for example, DMF, proved to be unsuitable for rinsing because potassium hydroxide is less soluble in them than the trichalcogenides. Therefore, the products were filtered under inert conditions by using a Schlenk‐frit.…”

“…Theredox reaction is promoted by the high concentration of hydroxide ions on the side of the reactants.Moreover,the hydroflux is highly hygroscopic.The initially contained water but also water formed through the reaction are strongly bonded to hydroxide ions.Thereby,the activity of the water is considerably reduced, which does not only decrease its vapor pressure and drives the reaction but obviously prevents the hydrolysis of the water sensitive trichalcogenides.O nt he other hand, the reaction diluted the hydroflux so that it did not solidify upon cooling to room temperature.W ashing of the reaction product with ap rotic solvent, for example,a n alcohol, strongly increases the activity of water and thereby induces the decomposition of K 2 Ch 3 .Similar observations had been made for other water sensitive products from hydroflux syntheses,f or example,K 2 [Fe 2 O 3 (OH) 2 ]o rT l 3 IO. [27,28] Also several aprotic polar solvents,f or example,D MF,p roved to be unsuitable for rinsing because potassium hydroxide is less soluble in them than the trichalcogenides.T herefore,t he products were filtered under inert conditions by using aSchlenk-frit. Theyields with respect to the used ChO 2 were 90 %for K 2 Te 3 ,60% for K 2 Se 3 and 80 %for K 2 Se 2 Te,related to the solubility of the diverse chalcogenide species.T he adhering KOHtogether with the genuine moisture-sensitivity of K 2 Ch 3 necessitated storage and handling of the crystals under inert conditions (argon).…”

Chalkogenide durch Reduktion ihrer Dioxide in ultra‐alkalischen Medien

“…Ähnliche Beobachtungen wurden auch bei anderen wasserempfindlichen Produkten aus Hydrofluxsynthesen gemacht, z. B. K 2 [Fe 2 O 3 (OH) 2 ] oder Tl 3 IO [27, 28] . Auch mehrere aprotische, polare Lösungsmittel, z.…”

“…Des Weiterem wurden farblose Lçsungen erhalten, wenn den gefärbten Dichalkogenidlçsungen bei Raumtemperatur gelçstes As 2 O 3 zusetzt wurde.B eide Beobachtungen deuten auf die Bildung von Monochalkogenid-Anionen Ch 2À hin. Gleichung (4) fasst die Reduktion der Dichalkogenid-Anionen zusammen: [27,28] Rçntgenbeugungsexperimente an schwarzen Einkristallen von K 2 Se 3 (Cmc2 1 )u nd K 2 Te 3 (Pnma)b estätigten die bekannten Strukturen. [4,5] [58] Angewandte Chemie Forschungsartikel 22746 www.angewandte.de Se-Te-Se Winkel von 97.6(1)8 8.D as (TeSe 2 ) 2À -Anion wurde bereits (2,2,2-crypt-K) 2 (TeSe 2 )•en (en = Ethylendiamin) [29] und [Mn(en) 3 ](TeSe 2 ) [30] beobachtet und weist darin Te -Se-Bindungslängen von etwa 250 pm und 250.3(1) pm sowie Se-Te -Se Winkel von 111.3(1)8 8 bzw.1 02.6(1)8 8 auf.I nd iesen Strukturen sind die (TeSe 2 ) 2À -Anionen weit voneinander getrennt und interagieren darüber hinaus mit den Wasserstoffatomen der organischen Liganden.…”