Über Schwermetallamide. VI. Thorium‐imido‐diamid und sein amphoteres Verhalten

Abstract

Durch Umsatz von Kaliumthoriumnitrat K2Th(NO3) 6 in flüssigem Ammoniak mit steigenden Mengen Kaliumamids wurden folgende Bodenkörper erhalten: Thoriumimido‐diamid HNTh(NH2)2(A), (HN)2ThNH2K (I), HNTh(NH2)3K (II), Th2(NH)3(NH2)4K2 (III). Alle Reaktionsprodukte sind nicht kristallin und stellen mehr oder weniger hochpolymere Verbindungen dar. Das wahrscheinlich primär entstehende Thorium(IV)‐ amid Th(NH2)4 zerfällt unterhalb 0° C spontan in A, das bei 25° in Th2(NH)3(NH2)2 (B) übergeht. Bei 100° C bildet sich hieraus Th(NH)2 (C) und weiter bei 130° C Th3N4 (D). Auch dieses Nitrid ist röntgenamorph (Flüssigkeitsdiagramm). A reagiert mit NH4J in flüssigem NH3 unter Bildung von Th(NH3)8J4; es reagiert also mit Ammono‐Säuren und Basen (Bildung der Amidosalze I, II und III; amphoteres Verhalten). Dem Amidosalz II kann durch Reaktion mit einer äquivalenten Menge NH4J alles Kalium entzogen werden. Das hierbei primär entstehende Th(NH2)4 zerfällt spontan unter NH3‐ Abspaltung; bei 25° C wird Dithorium‐triimido‐diamid (B) erhalten. Durch thermischen Abbau gehen II und III in I über; bei 270° C entsteht das Nitridosalz K3Th3N5 (IV). Bei 290–425° C zersetzt sich IV unter Bildung von röntgenamorphem ThN.

Rb2[U(NH2)6], a Rubidium Hexaamidouranate(IV) obtained from the Reaction of UI3 with RbNH2 in Anhydrous Ammonia

“…Both we deem possible. The pyrophoric behavior and the tendency to detonate upon air contact make it plausible that we have obtained the complex amide Rb 2 [U(NH 2 ) 6 ] as Schmitz‐Dumont has reported thorium amido complexes that were pyrophoric and exploded vigorously upon air contact, as well . They reported thermal decomposition reactions according to the following Equation (6), Equation (7), Equation (8), and Equation (9): …”

“…The obtained nitride K 3 Th 3 N 5 still reacted explosively with air. When the compound was heated even further, elemental potassium was released [Equation (10)] …”

“…The pyrophoric behavior and the tendency to detonate upon air contact make it plausible that we have obtained the complex amide Rb 2 [U(NH 2 ) 6 ] as Schmitz-Dumont has reported thorium amido complexes that were pyrophoric and exploded vigorously upon air contact, as well. [26] They reported thermal decomposition reactions according to the following Equation 6, Equation 7, Equation 8, and Equation (9): [26] K The obtained nitride K 3 Th 3 N 5 still reacted explosively with air. When the compound was heated even further, elemental potassium was released [Equation (10)].…”

“…When the compound was heated even further, elemental potassium was released [Equation (10)]. [26] K 3 Th 3 N 5 Ǟ 270°C 3 ThN + 3 K + N 2 (10) It is known that the heavier alkali metal amides can be decomposed above their melting points into the elements. [15] The vigorous reaction of Rb 2 [U(NH 2 ) 6 ] in air could therefore be not only due to exothermic protolysis, hydrolysis and oxidation reactions, but may be also due to a thermal decomposition induced by reaction heat.…”

Crystal chemistry of inorganic nitrides

“…The amides and imides of thorium can be formed at high pressures t400 600 MPa), although Th(NHe), , also can be formed from KeThINO,~)~, in liquid ammonia [254]. The structure of brown Th~N 4 is best described as hhc packing of Th atoms with nitrogen atoms in two layers of octahedral holes lollowcd by a layer in the tetrahedral holes [255].…”