Structural Relationships and Absorption Spectroscopy of beta-[NH4][UF5] and [NH4][Pu3F13]

beta-[NH4][UF5] and [NH4][Pu3F13]have been prepared by mild hydrothermal reactions. Their single-crystal structures have been observed to offer unexpected similarities in topology. beta-[NH4] [UF5] (P2(1/n)) forms an anionic layer structure held together by electrostatic attraction to interlayer ammonium cations. [NH4] [Pu3F13] (Pmc2(1)) forms a pseudolayer network with ammonium cations in well-defined voids. The layers found in both species are reminiscent of those previously observed in beta-Na[UFs]. While beta-[NH4] [UF5] almost repeats this structure directly, [NH4] [Pu3F13] features a doubling of this sheet structure due to a crystallographic mirror plane. The UV-visible-NIR absorption spectra of these structures are compared to those of published structures, and prospects for further work on these and related species are discussed.