Darstellungsmethoden und Kristallstrukturen quaternärer Chalkogenide, die Seltenerdmetalle und Münzmetalle enthalten : mit einem Appendix zu Alkalimetall Thiotelluraten

The main purpose of this work was to extend the knowledge about quaternary rare-earth metal coinage-metal chalcogenides containing alkali-metals toward heavy chalcogens, and then to explore the possibility of accommodating other possible metal(I)-cations instead of the alkalimetals. While some new quaternary structures occurred with tellurium, many isostructural compounds to RbAg3Sm2Se5 could be reproduced with selenium and sulfur by substituting not only the coinage-metal but also the alkali-metals. A substitution of alkali-metal with the pseudo-alkali-metal thallium(I) was successful with copper as coinage-metal. Thus, not only the alkali-metal character of the thallium(I) was confirmed but further properties typical for the new quaternary thallium(I)-copper-rare-earth-chalcogenide structures were detected. Besides the targeted compounds, some interesting side products namely chalcogenides and a few thiotellurates were also obtained. The chalcogenides comprise the ternary tellurides AYTe2 (A = K, Rb) and ASc5Te8 (A = Rb and Cs), the selenide EuSc2Se4 as well as the quaternaries of the composition NaLnSc4Ch8 (Ln = La - Sm; Ch = S and Se). The thiotellurates with compositions Cs2TeS3 and A2TeS2 (A = K - Cs) were identified and then synthesized as target products before they were structurally characterized. The latter form a new class of thiotellurates.Die Zielsetzung der vorliegenden Arbeit bestand darin neue quaternäre Selten-Erd Metall Münzmetall Chalkogenide, welche Alkali-Metalle und schwere Chalkogene enthalten zu synthetisieren. Weiterhin sollte der mögliche Einbau von Metal(I) anstatt Alkali-Metall untersucht werden. Während Synthesen mit Tellur zu einigen neue quaternären Verbindungen geführt haben, war es bei Synthesen mit Selen und Schwefel möglich RbAg3Sm2Se5 isotype Verbindungen durch Substitution der drei jeweiligen Kationenarten zu erhalten. Das Alkali-Metall konnte durch das Pseudo-Alkali-Metall Thallium(I) ersetzt werden, wenn Kupfer als Münzmetall eingesetzt wurde. S wurde nicht nur der Alkali-Metall Charakter des einwertigen Metals(I), bestätigt sondern auch typische Eingenschaffen neuer quaternäre Thallium(I)-Kupfer-Selten-Erd-Chalcogeniden untersucht. Neben diesen Zielverbindungen wurden, einige interessante Nebenprodukte gefunden. Unter diesen waren sowohl Chalkogenide als auch Thiotellurate. Bei den Chalcogeniden handelt es sich am die ternären Telluride AYTe2 (A = K, Rb) und ASc5Te8 (A = Rb, Cs), das Selenid EuSc2Se4, ebenso wie die Sulfide und Selenide der Zusammensetzung NaLnSc4Ch8 (Ln = La - Sm, Ch = S, Se). Die Thiotellurate der Zusammensetzungen Cs2TeS3 und A2TeS2 (A = Rb, Cs) wurden identifiziert, strukturell charakterisiert und anschließend gezielt hergestellt. Letztere mit zwei neuen Strukturtypen bilden eine neue Klasse von Alkali-Metall Thiotelluraten

A₆U₃Sb₂P₈S₃₂ (A = Rb, Cs): Quinary Uranium(IV) Thiophosphates Containing the [Sb(PS₄)₃]^6– Anion

The reaction of A₂S₃/U/P₂S₅/S at 500 °C affords the quinary U­(IV) thiophosphates A₆U₃Sb₂P₈S₃₂ (A = Rb, Cs). These compounds contain {U₃(PS₄)₂[Sb­(PS₄)₃]₂}^6– layers separated by alkali metal cations. The layers are composed of trimeric uranium units connected to each other by the thiophosphato-antimonite anion, [Sb­(PS₄)₃]^6–. This unit contains a central Sb­(III) cation bound by three [PS₄]^3– anions, creating a trigonal pyramidal environment around Sb­(III). Each uranium cation is surrounded by eight sulfides in a distorted square antiprism that shares two edges with two other US₈ units to form a trimeric [U₃S₁₈]^24– cluster. Magnetic susceptibility measurements indicate that the close proximity of the U­(IV) within these clusters leads to antiferromagnetic ordering at 53 K. Reflectance spectroscopy indicates that these compounds are semiconductors with a band gap of 1.48 eV

A₆U₃Sb₂P₈S₃₂ (A = Rb, Cs): Quinary Uranium(IV) Thiophosphates Containing the [Sb(PS₄)₃]^6– Anion

The reaction of A₂S₃/U/P₂S₅/S at 500 °C affords the quinary U­(IV) thiophosphates A₆U₃Sb₂P₈S₃₂ (A = Rb, Cs). These compounds contain {U₃(PS₄)₂[Sb­(PS₄)₃]₂}^6– layers separated by alkali metal cations. The layers are composed of trimeric uranium units connected to each other by the thiophosphato-antimonite anion, [Sb­(PS₄)₃]^6–. This unit contains a central Sb­(III) cation bound by three [PS₄]^3– anions, creating a trigonal pyramidal environment around Sb­(III). Each uranium cation is surrounded by eight sulfides in a distorted square antiprism that shares two edges with two other US₈ units to form a trimeric [U₃S₁₈]^24– cluster. Magnetic susceptibility measurements indicate that the close proximity of the U­(IV) within these clusters leads to antiferromagnetic ordering at 53 K. Reflectance spectroscopy indicates that these compounds are semiconductors with a band gap of 1.48 eV

Synthesis, Structure, Magnetism, and Optical Properties of Cs₂Cu₃DyTe₄

CsCu₃DyTe₄ was prepared by reacting copper, dysprosium, and tellurium with cesium azide at 850 °C in a fused silica ampule. This new telluride crystallizes in the monoclinic space group <i>C</i>2/<i>m</i> with lattice dimensions of <i>a</i> = 16.462(4) Å, <i>b</i> = 4.434(1) Å, <i>c</i> = 8. 881(2) Å, β = 108.609(12)° with <i>Z</i> = 2. Its crystal structure is dominated by _∞²{[Cu₃DyTe₄]}^1– anionic layers separated by Cs⁺ cations. The copper cations are disordered over three different tetrahedral sites. The [DyTe₆]^9– polyhedra form infinite _∞¹{[DyTe₄]^5–} chains. Magnetism studies conducted on this semiconductor suggest complex magnetic interactions between the Dy³⁺ cations with a strong deviation from Curie-type behavior at low temperatures below 40 K

Incorporation of Cu²⁺ Ions into Nanotubular Uranyl Diphosphonates

Three new multidimensional polymetallic uranyl diphosphonates were crystallized under mild hydrothermal conditions: [Cu­(H₂O)]₂{(UO₂)₄F₂[(PO₃C₆H₄)­(C₆H₄PO₃H)₃]₂(bipym)}·6H₂O (<b>1</b>), [Cu­(H₂O)]₂{(UO₂)₄[(C₆H₄PO₃)­(C₆H₄PO₃H)]₄(bipym)} (<b>2</b>), and Cu­{(UO₂)­(C₆H₄PO₃)₂(bipym)}·H₂O (<b>3</b>). Compound <b>1</b> consists of UO₆F pentagonal bipyramids connected by diphosphonate moieties into a tubular channel. The Cu²⁺ cations are stabilized between the nanotubular subunits by 2,2′-bipyrimidine (bipym). The structure of <b>2</b> is similar to <b>1</b>, except that it consists of relatively rare UO₆ tetragonal bipyramids bridged by diphosphonate groups. Compound <b>3</b> also contains UO₆ tetragonal bipyramids. Unlike compounds <b>1</b> and <b>2</b>, only two of the tetradentate N atoms of the binucleating bipym group are coordinated. All three compounds show luminescent properties under ambient conditions, with evidence of the characteristic vibronically coupled charge-transfer based uranyl cation emissions

Incorporation of Cu²⁺ Ions into Nanotubular Uranyl Diphosphonates

Three new multidimensional polymetallic uranyl diphosphonates were crystallized under mild hydrothermal conditions: [Cu­(H₂O)]₂{(UO₂)₄F₂[(PO₃C₆H₄)­(C₆H₄PO₃H)₃]₂(bipym)}·6H₂O (<b>1</b>), [Cu­(H₂O)]₂{(UO₂)₄[(C₆H₄PO₃)­(C₆H₄PO₃H)]₄(bipym)} (<b>2</b>), and Cu­{(UO₂)­(C₆H₄PO₃)₂(bipym)}·H₂O (<b>3</b>). Compound <b>1</b> consists of UO₆F pentagonal bipyramids connected by diphosphonate moieties into a tubular channel. The Cu²⁺ cations are stabilized between the nanotubular subunits by 2,2′-bipyrimidine (bipym). The structure of <b>2</b> is similar to <b>1</b>, except that it consists of relatively rare UO₆ tetragonal bipyramids bridged by diphosphonate groups. Compound <b>3</b> also contains UO₆ tetragonal bipyramids. Unlike compounds <b>1</b> and <b>2</b>, only two of the tetradentate N atoms of the binucleating bipym group are coordinated. All three compounds show luminescent properties under ambient conditions, with evidence of the characteristic vibronically coupled charge-transfer based uranyl cation emissions

Thermochromism, the Alexandrite Effect, and Dynamic Jahn–Teller Distortions in Ho₂Cu(TeO₃)₂(SO₄)₂

A 3d–4f heterobimetallic material with mixed anions, Ho₂Cu­(TeO₃)₂(SO₄)₂, has been prepared under hydrothermal conditions. Ho₂Cu­(TeO₃)₂(SO₄)₂ exhibits both thermochromism and the Alexandrite effect. Variable temperature single crystal X-ray diffraction and UV–vis–NIR spectroscopy reveal that changes in the Cu^II coordination geometry result in negative thermal expansion of axial Cu–O bonds that plays a role in the thermochromic transition of Ho₂Cu­(TeO₃)₂(SO₄)₂. Magnetic studies reveal an effective magnetic moment of 14.97 μB. which has a good agreement with the calculated value of 15.09 μB

Thermochromism, the Alexandrite Effect, and Dynamic Jahn–Teller Distortions in Ho₂Cu(TeO₃)₂(SO₄)₂

A 3d–4f heterobimetallic material with mixed anions, Ho₂Cu­(TeO₃)₂(SO₄)₂, has been prepared under hydrothermal conditions. Ho₂Cu­(TeO₃)₂(SO₄)₂ exhibits both thermochromism and the Alexandrite effect. Variable temperature single crystal X-ray diffraction and UV–vis–NIR spectroscopy reveal that changes in the Cu^II coordination geometry result in negative thermal expansion of axial Cu–O bonds that plays a role in the thermochromic transition of Ho₂Cu­(TeO₃)₂(SO₄)₂. Magnetic studies reveal an effective magnetic moment of 14.97 μB. which has a good agreement with the calculated value of 15.09 μB

From Yellow to Black: Dramatic Changes between Cerium(IV) and Plutonium(IV) Molybdates

Hydrothermal reactions of CeCl3 and PuCl3 with MoO3 and Cs2CO3 yield surprisingly different results. Ce3Mo6O24(H2O)4 crystallizes as bright yellow plates (space group C2/c, a = 12.7337(7) Å, b = 22.1309(16) Å, c = 7.8392(4) Å, β = 96.591(4)°, V = 2194.6(2) Å3), whereas CsPu3Mo6O24(H2O) crystallizes as semiconducting black-red plates (space group C2/c, a = 12.633(5) Å, b = 21.770(8) Å, c = 7.743(7) Å, β = 96.218(2)°, V = 2117(2) Å3). The topologies of the two compounds are similar, with channel structures built from disordered Mo(VI) square pyramids and (RE)O8 square antiprisms (RE = Ce(IV), Pu(IV)). However, the Pu(IV) compound contains Cs+ in its channels, while the channels in Ce3Mo6O24(H2O)4 contain water molecules. Disorder and an ambiguous oxidation state of Mo lead to the formula CsPu3Mo6O24(H2O), where one Mo site is Mo(V) and the rest are Mo(VI). X-ray absorption near-edge structure (XANES) experiments were performed to investigate the source of the black color of CsPu3Mo6O24(H2O). These experiments revealed Pu to be tetravalent, while the strong pre-edge absorption from the distorted molybdate anions leaves the oxidation state ambiguous between Mo(V) and Mo(VI)