Synthesis and Crystal Structure of KCuGd2S4: A Threedimensional Framework with Isolated Channels

Abstract

The reaction of K2S5, Cu, Gd, and S in a 2 : 1 : 2 : 4 molar ratio at 450 °C yields yellow‐orange needle‐like cuboids of the new quaternary compound KCuGd2S4. The crystal structure represents a novel three‐dimensional structure type of quaternary rare earth chalcogenides with alkali metal. The compound crystallizes in the orthorhombic space group Cmcm (No. 63) with a = 3.9921(1) Å, b = 13.523(3) Å, c = 13.802(3) Å, V = 745.1(3) Å3, Z = 4. In the structure GdS6 octahedra and CuS4 tetrahedra are joined by common edges and corners forming corrugated layers parallel to (010). The GdS6 octahedra are connected via common edges in the third dimension thus leading to the formation of a three‐dimensional tunnel structure. The potassium cations are confined within the pentagonal shaped channels and are surrounded by eight sulfide anions each.

Syntheses and Crystal Structures of CsCuNd2Se4 and CsCuGd2Te4: Two Non‐Isotypical Cesium Copper Lanthanide Chalcogenides with {}^1_\infty{[CuCh3]5–} Chains of Vertex‐Shared [CuCh4]7– Tetrahedra

“…So far, just singly occupied single‐channel structures (e.g. KCuGd 2 S 4 12 and CsCuNd 2 Se 4 ) or those with threefold occupied triple channels (e.g. Cs 3 Cu 5 Gd 4 Te 10 11) are known in quaternary compounds with the heavy chalcogenide anions.…”

“…CsCuNd 2 Se 4 crystallizes in the orthorhombic space group Cmcm and is isostructural with KCuGd 2 S 4 12. The crystallographically unique Nd 3+ cations at the Wyckoff position 8 f (symmetry: m ) are octahedrally coordinated by six Se 2– anions.…”

Tuning of Optical Band Gaps: Syntheses, Structures, Magnetic Properties, and Optical Properties of CsLnZnSe3 (Ln = Sm, Tb, Dy, Ho, Er, Tm, Yb, and Y)

“…These materials display a variety of layered and tunnel structure types in addition to interesting physical properties. Examples include RbLn 2 CuSe 4 (Ln = Sm, Gd, Dy), Rb 1.5 Ln 2 Cu 2.5 Se 5 (Ln = Gd, Dy), RbSm 2 Ag 3 Se 5 , BaLnMQ 3 (Ln = rare earth; M = Cu, Ag, Au; Q = S, Se, Te), − Ba 2 LnAg 5 S 6 (Ln = La, Y), KGd 2 CuS 4 , K 2 CeCu 2 S 4 , ALnCu 2 S 6 (A = K, Cs; Ln = La, Ce, Eu), − K 1.5 Dy 2 Cu 2.5 Te 5 , K 0.5 Ba 0.5 DyCu 1.5 Te 3 , ALnCuQ 3 (A = K, Cs; Ln = Ce, Th, U; Q = S, Se, Te), , K 2 CeAg 3 Te 4 , KCeCuTe 4 , and Rb 2 CeCu 3 Te 5 …”

New Layered Materials: Syntheses, Structures, and Optical and Magnetic Properties of CsGdZnSe3, CsZrCuSe3, CsUCuSe3, and BaGdCuSe3

“…The d-elements found in these compounds are typically coinage metals. Examples include RbLn 2 CuSe 4 (Ln = Sm, Gd, Dy), Rb 1.5 Ln 2 Cu 2.5 Se 5 (Ln = Gd, Dy), RbSm 2 Ag 3 Se 5 , BaLnMQ 3 (Ln = rare earth; M = Cu, Ag, Au; Q = S, Se, Te), − Ba 2 LnAg 5 S 6 (Ln = La, Y), KGd 2 CuS 4 , K 2 CeCu 2 S 4 , ALnCu 2 S 6 (A = K, Cs; Ln = La, Ce, Eu), − K 1.5 Dy 2 Cu 2.5 Te 5 , K 0.5 Ba 0.5 DyCu 1.5 Te 3 , CsUCuTe 3 , CsCeCuS 3 , K 2 CeAg 3 Te 4 , KCeCuTe 4 , and Rb 2 CeCu 3 Te 5 …”