LaS1.9, CeS1.9, PrS1.9, NdS1.9, and GdS1.9: Five new Lanthanide Polysulfides – Syntheses, Crystal Structures and their Structural Relationship to the ZrSSi TypeCrystals of the five new lanthanide polysulfides LaS1.9, CeS1.9, PrS1.9, NdS1.9, and GdS1.9 have been prepared by different synthetic routes. According to X‐ray structure analyses, the compounds adopt the tetragonal CeSe1.9 type structure (space group: P42/n, no. 86) with the lattice parameters a = 9.111(1) Å, c = 16.336(2) Å (LaS1.9), a = 9.015(3) Å, c = 16.168(4) Å (CeS1.9), a = 8.947(3) Å, c = 16.054(4) Å (PrS1.9), a = 8.901(3) Å, c = 16.022(4) Å (NdS1.9), and a = 8.714(1) Å, c = 15.791(1) Å (GdS1.9), respectively. The crystal structure consists of puckered [LnS] double slabs and planar sulfur layers alternating along [001]. Each planar sulfur layer contains disulfide dumbbells, isolated anions and ordered vacancies.

During attempts to synthesize copper(I) praseodymium(III) disulfide (CuPrS 2 ) from 1 : 1 : 2-molar mixtures of the elements (Cu, Pr and S) after seven days at 850°C in sealed evacuated silica tubes the almost quantitative formation of the quaternary chalcogenide CuPrOS indicated that some massive oxygen-contaminant (most probably surfaceoxidized praseodymium metal) must have been present. The unexpected product becomes even single-crystalline and emerges as yellowish green transparent platelets with square cross-section when equimolar amounts of CsCl work as fluxing agent. The crystal structure of CuPrOS (tetragonal, P4/nmm; a = 394.19(4), c = 843.98(9) pm; c/a = 2.141, Z = 2) can be described as an anionic PbFCl-type arrangement according to 2Pr 3+ in squareantiprismatic coordination of four F ± and four S 2± anions which is ªstuffedº by Cu + cations within tetrahedral interstices between the S 2± double layers for charge balance. Another description emphasizes two kinds of layers (anionic 2 I {[(Cu + )(S 2± ) 4/4 ] ± } and cationic 2 I {[(O 2± )(Pr 3+ ) 4/4 ] + } ones) consisting of condensed [(Cu + )(S 2± ) 4 ] 7± and [(O 2± )(Pr 3+ ) 4 ] 10+ tetrahedra, respectively, each of which share four of their six edges. Both types of square layers exhibit the same topology and are alternatingly sheethed parallel (001). The most important internuclear distances range from 233 (d(O±Pr), 4´) via 243 (d(Cu±S), 4´) up to 320 pm (d(Pr±S), 4´). Aufgrund ihres Potentials als Cu + -Kationenleiter sind terna È-re Kupfer(I)-Selten-Erd(III)-Sulfide der Zusammensetzung CuMS 2 (M = Sc, Y, La; Ce±Lu [1, 2]; Strukturtypen: A-CuLaS 2 (monoklin, P2 1 /c) [3], B-CuYS 2 (orthorhombisch, Pnma) [4] und C-CuScS 2 (trigonal, P3m1) [5]) immer wieder Gegenstand von Forschungsaktivita È ten gewesen. Auch u È ber die Kristallstrukturen quaterna È rer Kupfer(I)-Selten-Erd(III)-Chalkogenide mit zwei unterschiedlichen Chalkogenid-Anionen (z. B. CuMOS [6], CuMOSe [7], CuMOTe [7] im AgLaOS-Typ [8] sowie zwei Formen von CuMSTe (M = La, Sm) [9]) ist bereits berichtet worden. Von einem unerwarteten Nebenprodukt (CuPrOS [10] isotyp mit CuLaOS [6]) bei Versuchen zur Synthese von CuPrS 2 [11] unter sauerstoffkontaminierten Bedingungen handelt nachfolgender Kurzartikel. Experimentelles Bei der Umsetzung von elementarem Kupfer (Aldrich; 99,999%) und Praseodym (Heraeus-ChemPur; 99,99%) mit Schwefel (Alfa-Aesar Johnson-Matthey; 99,9995%) in evakuierten, gasdicht abgeschmolzenen Quarzglasampullen (850°C, 7 d; molares Verha È ltnis: Cu : Pr : S = 1 : 1 : 2; Zusatz von a È quimolaren Mengen an CsCl (E. Merck; suprapur) als Fluûmittel) entsteht durch den Einsatz von oberfla È chlich oxidiertem Praseodym an Stelle des erhofften Zielproduktes CuPrS 2 nahezu quantitativ eine gelbgru È ne Substanz in Form von luft-und hydrolyseunempfindlichen, du È nnen, pla È ttchenfo È rmigen Einkristallen mit quadratischem Querschnitt. Nach Ausweis der Ro È ntgenstrukturanalyse handelt es sich dabei

No abstract

in Gegenwart von NaF als Flußmittel in evakuierten Goldampullen ergibt bei einer Temperatur von 1000°C und einer Temperzeit von 10h dunkelrote, plättchenförmige Einkristalle von Eu 5 F[SiO 4 ] 3 . Ebenfalls dunkelrote, jedoch säulenförmige Einkristalle von Yb 5 S[SiO 4 ] 3 werden bei der Umsetzung von Yb, Yb 2 O 3 und S mit SiO 2 in Anwesenheit von CsBr als Flußmittel in evakuierten Kieselglasampullen bei 850°C und 7d Temperzeit erhalten. Beide Verbindungen kristallisieren hexagonal (P6 3 /m, Z ϭ 2; Eu 5 F[SiO 4 ] 3 : a ϭ 954,79(9), c ϭ 704,16(6) pm; Yb 5 S[SiO 4 ] 3 : a ϭ 972,36(9), c ϭ Abstract. By the reaction of Eu, EuF 3 , Eu 2 O 3 with SiO 2 in evacuated gold ampoules, using NaF as flux, at a temperature of 1000°C for ten hours, dark-red, platelet-shaped single crystals of Eu 5 F[SiO 4 ] 3 are obtained. Similarly dark-red, but pillar-shaped single crystals of Yb 5 S[SiO 4 ] 3 are obtained by the reaction of Yb, Yb 2 O 3 and S with SiO 2 in the presence CsBr as flux in evacuated silica ampoules at 850°C and an annealing time of seven days. Both compounds crystallize hexagonally (P6 3 /m, Z ϭ 2; Eu 5 F-[SiO 4 ] 3 : a ϭ 954.79(9), c ϭ 704.16(6) pm; Yb 5 S[SiO 4 ] 3 : a ϭ 972.36(9), c ϭ 648.49(6) pm) in the case of Eu 5 F[SiO 4 ] 3 analogous to the mineral fluorapatite and for Yb 5 S[SiO 4 ] 3 as a Einleitung Der Strukturtyp des Minerals Apatit Ca 5 (F,Cl,OH)[SiO 4 ] 3 (hexagonal, P6 3 /m) [1, 2] zeigt eine 648,49(6) pm), im Falle von Eu 5 F[SiO 4 ] 3 analog zum Mineral Fluorapatit und Yb 5 S[SiO 4 ] 3 im Bromapatit-Typ. Die isolierte [SiO 4 ] 4Ϫ -Tetraeder enthaltende Kristallstruktur unterscheidet zwei Selten-Erd-Kationenlagen mit Koordinationszahlen von neun (M1) und sieben (M2), wobei die Lage M1 des Europium-Fluoridsilicats fast ausschließlich mit Eu 2ϩ -Kationen besetzt ist, während sie beim Ytterbium-Sulfidsilicat im Verhältnis 1 : 1 zwei-und dreiwertige Yb-Kationen enthält. Dagegen befinden sich in beiden Fällen nur M 3ϩ -Ionen auf der M2-Lage.bromapatiteϪtype variety. The crystal structure containing isolated [SiO 4 ] 4Ϫ tetrahedra distinguishes two rare-earth cation positions with coordination numbers of nine (M1) and seven (M2), in which the position M1 of the europium fluoride silicate is almost exclusively occupied by Eu 2ϩ cations, whereas in ytterbium sulfide silicate it contains di-and trivalent Yb cations in the ratio 1 : 1. In both cases, however, the M2 position is only populated with M 3ϩ .

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.