ISSN:
0044-2313
Keywords:
Carbonates
;
Lanthanoids
;
Synthesis
;
Crystal Structure
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Potassium Lanthanoid Carbonates, KM(CO3)2 (M = Nd, Gd, Dy, Ho, Yb)The ternary potassium lanthanoid carbonates KM(CO3)2 (M = Nd, Gd, Dy, Ho, Yb) are obtained as single crystals by high-pressure synthesis in steel autoclaves with carbon dioxide (starting pressure approximately 50 bar at ambient temperature) in the presence of water from a mixture of K2CO3 and MCl3 · x H2O (x = 7 and 6, respectively) at 450°C within 4 weeks. In KNd(CO3)2 (orthorhombic, Pmn21, Z = 4, a = 973.1(2), b = 645.69(8), c = 855.58(14) pm, R1 = 0.0763 for all data) [Nd-μ1-(CO3)3-μ2-(CO3)3] polyhedra are connected three-dimensionally to [Nd(CO3)] layers as similarly in UO2(CO3); these layers are connected via the second half of the carbonate ligands and K+ ions. In KDy(CO3)2 (monoclinic, C2/c, Z = 4, a = 853.8(2), b = 949.1(1), c = 694.5(1) pm, β = 111.1(2)°, R1 = 0.0266 for all data) and in the isotypic carbonates KM(CO3)2 (M = Gd, Ho, Yb) the polyhedra [Dy-μ1-(CO3)4-μ2-(CO3)2] and [K-μ1-(CO3)6] are connected to “syndiotactic” zig-zag chains and by further O-ligator atoms of the carbonate ligands such that each zig-zag chain is surrounded by four unlike chains and vice versa.
Notes:
Die ternären Kalium-Lanthanoid-Carbonate KM(CO3)2 (M = Nd, Gd, Dy, Ho, Yb) erhält man in Form von Einkristallen durch Hochdrucksynthese im Stahlautoklaven mit Kohlendioxid (Anfangsdruck etwa 50 bar bei Raumtemperatur) in Anwesenheit von Wasser aus Gemengen von K2CO3 und MCl3 · x H2O (x = 7 bzw. 6) bei 450°C innerhalb von 4 Wochen. In KNd(CO3)2 (orthorhombisch, Pmn21, Z = 4; a = 973,1(2); b = 645,69(8); c = 855,58(14) pm; R1 = 0,0763 für alle Daten) werden Polyeder [Nd-μ1-(CO3)3-μ2-(CO3)3] ähnlich wie in UO2(CO3) zu Schichten [Nd(CO3)] verknüpft; die Schichten werden über die zweite Hälfte von CO32--Liganden sowie durch K+ dreidimensional verknüpft. In KDy(CO3)2 (monoklin, C2/c, Z = 4; a = 853,8(2); b = 949,1(1); c = 694,5(1) pm; β = 111,1(2)°; R1 = 0,0266 für alle Daten) und in den isotypen Carbonaten KM(CO3)2 (M = Gd, Ho, Yb) sind die Polyeder [Dy-μ1-(CO3)4-μ2-(CO3)2] und [K-μ1-(CO3)6] jeweils zu „syndiotaktischen“ Zick-Zack-Ketten und weiter über gemeinsame O-Ligatoratome der Carbonat-Liganden so verknüpft, daß die Zick-Zack-Ketten jeweils von vier Ketten der anderen Sorte umgeben sind.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/zaac.19976231115
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