The chemistry of uranylvanadates with trimetavanadate ions and layer structure (uvanite). P. 2

The interlayer cations of uvanite can be exchanged quantitatively by n-alkylammoniumions according to M + [UO 2 V 3 O 9 ] + C n H 2n+1 NH 3 + ⇄ C n H 2n+1 NH 3 [UO 2 V 3 O 9 ] + M + . In the stoichiometric compounds the alkyl chains of the cations (n= 6-18) are poorlyordered in monolayers and oriented nearly perpendicular to the uranyltrimetavanadatelayers though the space filling is unfavorable with this arrangement. During the cationexchange at pH = 7-9 additional free amine molecules are taken up yielding 1:1 intercalationcomplexes (C n H 2n+1 NHs) (C n H an+1NH2) [UO 2 V 3 O 9 ] with close-packed, well ordered monolayers of alkyl compounds. With excess of pureamines or pure alkanols 1: 3 intercalation complexes (CnH 2n+1 NH 3 ) (CnH 2n+1 NH 2 ),[UO 2 V 3 O 9 ] or (C n H 2n+1 NH 3 ) (C n ·H 2n+1 OH )s[UO 2 V 3 O9 (n, n′ = 6-18] are formed with the alkyl chains ordered to bimolecular layers. These complexes rearrange at higher temperature into new phases as a consequence of rotationalisomerisation of the alkyl chains.