[en] The solubility and reactivity of metal halides, transition metal halides, and actinoid halides in liquid ammonia can lead to new starting materials for the synthesis of fluorides in low oxidation states or for nitrides via a ''low-temperature route''. In this context the ability of metal and actinoid halides to act as an acceptor for or donor of fluoride ions is also of interest. Four different systems were investigated in this study. In the first section, the synthesis and characterization of new compounds were carried out in the system CuX/NH_3 (X = F, Cl, Br, I, and CN) and lead to a ligand stabilized monovalent copper fluoride as a main result. In the second section, the solubility of uranyl compounds and uranium halides in liquid ammonia was investigated and the products were characterized. In the third section, alkali metal thorates were synthesized. Their solubility in liquid ammonia and their behavior as an acceptor for fluoride ions was investigated. In the last section, the results on the solubility behavior of transition metal halides in liquid ammonia and their coordination behavior are presented. In the first system CuX/NH_3 several new compounds, such as [Cu(NH_3)_3]X (X = Br, I or CN) were synthesized and characterized. The reactions of this compounds with fluoride ion donors (NH_4F or Me_4NF) led unfortunately not to the monovalent copper fluoride CuF. The comproportionation reaction of Cu and CuF_2 in liquid ammonia lead to the compounds [Cu(NH_3)_3]_2[Cu_2(NH_3)_2] . 4 NH_3 and [Cu(NH_3)_2]F . NH_3. For the preparation of binary CuF, various decomposition experiments were executed on the compound [Cu(NH_3)_2]F . NH_3 which resulted in different decomposition products. In additional studies various complexes of divalent copper was investigated and with the compound [Cu(NH_3)_5]F_2 . NH_3 the solubility of fluoride containing substances in liquid ammonia could be shown. Studies of six- and tetravalent uranium compounds led to the characterization of pentaammine complexes of the dioxidouranium cation which also was shown to form di-, tetra- or octanuclear networks via oxygen bridges. In the tetra- and octanuclear compounds, penta- and hexavalent uranyl cations seem to be present in one compound. The reactions of TiCl_3 and UF_4 and the reaction of Cs[UO_2(NO_3)_3] and CuF_2, yielded the new compounds [UF(NH_3)_8]Cl_3 . 3,5 NH_3 and Cs[UO_2F_3(NH_3)_2], respectively. Both compounds demonstrated on the one hand the possibility of the exchange of halides and on the other hand the ability to accept fluoride ions. Additionally, a new method for the synthesis of uranyl chloride is presented. Experiments regarding the solubility of metal halides of group 2, 4, and 5 of the periodic table yielded the ammonia complexes of [Ca(NH_3)_8]X_2 (X = Br and I), [Ti(NH_3)_8]Cl_3 . 6 NH_3, and mer-[VF_3(NH_3)_3]. Instead of the expected tetragonal antiprism for the eightfold coordinated Ca"2"+ ion, a coordination polyhedron best described as a twofold capped trigonal prism and for the Ti"3"+ ion an untypical eightfold coordination can be observed. Characterization of the novel compounds was carried out by single crystal and powder X-ray diffraction, infrared and Raman spectroscopy, thermogravimetry and mass spectrometry.

[en] The reaction of K_2Th(NO_3)_6 and UF_4 with liquid ammonia as a solvent leads on air to planar colorless crystals of ditriakontaammine hexadeca-μ-fluorido tetra-μ_3-oxido tetra-μ_4-oxido decathorium(IV) octanitrate ammonia (1/19.6), [Th_1_0F_1_6O_8(NH_3)_3_2](NO_3)_8.19.6 NH_3 (1). The compound crystallizes in the tetragonal space group P anti 42_1c (no. 114) with a = 18.4167(2), c = 14.7920(4) Aa, and V = 5017.1(2) Aa"3 at 123 K with Z = 2. The crystal structure shows the presence of a decanuclear thorium core [Th_1_0O_4]"3"2"+ similar to an ''inverse'' P_4O_1_0 or like 1,3,5,7-tetramethyladamantane. Such a complex seems to be the largest thorium complex reported so far - a finding that is of great importance for the knowledge of actinoid speciation in solutions. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] Vanadium trifluoride reacts with dry liquid ammonia under the formation of lilac plate-shaped crystals of mer-triammine trifluorido vanadium(III) (1), mer-[VF_3(NH_3)_3]. Single-crystal X-ray analysis was carried out at low temperature to elucidate the structure. The compound crystallizes in the monoclinic space group P2"1/c with a = 5.7284(4), b = 9.2033(5), c = 10.5271(6) Aa, beta = 91.795(6)°, and V = 554.72(6) Aa"3 at 123 K with Z = 4. The discrete [VF_3(NH_3)_3] molecules are interconnected by hydrogen bonds.

[en] Uranyl chloride UO_2Cl_2 and uranyl fluoride UO_2F_2 react with dry liquid ammonia under the formation of traffic-green crystals of pentaammine dioxido uranium(VI) dichloride ammonia (1/1) [UO_2(NH_3)_5]Cl_2.NH_3 (1) and sulfur-yellow crystals of triammine difluorido dioxido uranium(VI) ammonia (2/2) [UO_2F_2(NH_3)_3]_2.2NH_3 (2), respectively. Low-temperature X-ray structure analyses on single crystals of the two compounds were conducted. Compound 1 crystallizes in the orthorhombic space group Cmcm with a = 12.7865(2), b = 10.5106(2), c = 8.7089(2) Aa, V = 1170.45(4) Aa"3 at 123 K with Z = 4. Compound 2 crystallizes in the orthorhombic space group Pnma with a = 20.8451(5), b = 9.1267(2), c = 8.3371(2) Aa, V = 1586(6) Aa"3 at 123 K with Z = 4. Further investigations on the room-temperature decomposition products of compounds 1 and 2 by Raman and IR spectroscopy, TGA MS and X-ray powder diffraction measurements and deuteration studies led to the identification of triammine dichlorido dioxido uranium(VI) UO_2Cl_2(NH_3)_3 (3) and triammine difluorido dioxido uranium(VI) UO_2F_2(NH_3)_3 (4) in the form of fern-green and zinc-yellow powders. Quantum chemical studies at the DFT-PBE0/TZVP level of theory support the experimental observations and also show that the O≡U≡O triple bonding in the [UO_2F_2(NH_3)_3] molecule of compound 2 is weaker in comparison to the one in the [UO_2(NH_3)_5]"2"+ dication of compound 1. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] The coordination center of the Bundesamt fuer Strahlenschutz is performing annual ring experiments for in-vivo and in-vitro measuring points. This procedure allows checking the measuring data and the competence of the personnel. In the last years these tests included also radionuclides that are important in radiation emergency protection. Case studies for dose determination based on incorporation scenarios are included.

[en] This article presents an overview of recent advancements in the field of uranium chemistry, paying special attention to the preparation of starting materials and to the chemistry of uranium halides in liquid ammonia. Where suitable, insights into the chemistry of thorium are also presented. Herein, we report upon the crystal structures of several ammine complexes as well as their deprotonation products. Specific examples of hydrolysis products in liquid ammonia are showcased. Additionally, advancements in the preparation of uranium cyanides are presented.

[en] Alkali and alkaline earth metal tetrafluorobromates M"IBrF_4, M"I"I(BrF_4)_2 (M"I = Na-Cs, M"I"I = Sr, Ba) can be synthesized from the respective fluorides and BrF_3. By the reaction of CsF with an excess of BrF_3, the compound cesium tetrafluoridobromate(III) bromine trifluoride (1/1), CsBr_2F_7 (1), was obtained in the form of a colorless powder and as single crystals. Shown by X-ray diffraction on single crystals, its Br_2F_7"- anion is neither planar, nor is its Br-μ-F-Br unit linear, as previously deduced by Raman spectroscopy. In stoichiometric reactions of CsF with BrF_3, the compound cesium tetrafluoridobromate(III), CsBrF_4 (2), was obtained as a colorless powder. Compound 2 can also be obtained from compound 1 by evacuation. The crystal structure of CsBrF_4 (2) was elucidated by Rietveld refinement on its X-ray powder pattern. Its structure is not isotypic to MBrF_4 (M = Na, K, Rb, NO) but isotypic to CsAuF_4. CsBr_2F_7 is, however, not isostructural to CsAu_2F_7. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)