Noncentrosymmetric rare-earth copper gallium chalcogenides RE3CuGaCh7 (RE=La–Nd; Ch=S, Se): An unexpected combination

Sodium-Stuffed Open-Framework Quaternary Chalcogenide Built with (Cu2Ga6S18)16– Ribbons Cross-Linked by Unusual Linear Cu(I) Pillars

“…All Na atoms occupy the tunnels that resulted from interconnection of these anionic (Cu 2 Ga 6 S 18 ) 16– ribbons with Na–S distances in the range of 2.729(2)–3.337(3) Å (Figure b). All Ga–S and Cu1–S bond distances are in the ranges of 2.2304(11)–2.3315(11) and 2.3587(12)–2.4398(12) Å, respectively, which are in agreement with Ga–S [2.261(2)–2.304(2) Å] and Cu–S distances [2.383(2)–2.400(2) Å] in related compounds. , The bond distance for linearly coordinated Cu [Cu2–S, 2.1597(11) Å] is close to Cu–S distances found in several linearly coordinated Cu sulfide-based compounds. ,− S–Ga–S and S–Cu1–S bond angles are in the ranges of 99.11(4)–118.69(4)° and 104.02(4)–116.61(4)°, respectively, suggesting the highly distorted tetrahedral geometry for GaS 4 and Cu1S 4 , respectively, whereas a S–Cu2–S bond angle of 180° reflects a perfectly linear coordination.…”

“…These building units can be simple tetrahedral to complex supertetrahedral units, and various modes of connectivity between the tetrahedral units can give rise to edge- or corner-shared finite and infinite chains and ribbons . Interconnections between these building units via main group or transition metals would give access to various two- and three-dimensional structures, often an open framework with varied sizes of pores and channels because of the availability of a range of supertetrahedral and other simple/complex units of different shapes and dimensions. − The rich structural chemistry also endows fascinating physicochemical properties. For example, the negatively charged frameworks often host alkali ions that are highly mobile by virtue of the weak interactions with soft chalcogen ligands leading to superionic conductors .…”

“…However, under purely solid-state synthetic conditions at moderately high temperatures, the role of copper in building a specific structural component has not been explored extensively, especially in combination with Ga-chalcogenide networks. Ga is unique in many ways as it can form a myriad of chalcometallates encompassing a simple tetrahedral unit, , an edge-shared tetrahedral dimer, and supertetrahedral units to a range of extended Ga-chalcogenide networks. ,,, Toward this goal, we sought to synthesize a quaternary composition in the A–Cu–Ga–Q series (A = alkali metal, and Q = chalcogen). In this effort, we have employed solid-state metathesis reaction between Na 6 Ga 2 S 6 and CuCl to replace part of the Na ions with Cu + and form a three-dimensionally connected network.…”

Two new phases in the ternary RE–Ga–S systems with the unique interlinkage of GaS4building units: synthesis, structure, and properties

“…Recently, quaternary chalcogenides that contain a rare-earth metal together with a group 13 main-group metal (e.g., Ga and In) are of great interest due to their fascinating structural chemistry and interesting physical properties including magnetic, photo-response, photoelectric, and nonlinear optical (NLO) properties. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] For example, 1D infinite anionic chains containing the compound Ba 2 REMQ 5 (RE = rare-earth metal; M = Ga, In; Q = S, Se, Te) offer flexibility in band gap engineering by controlling the composition and show weak short-range antiferromagnetic interactions between the adjacent RE 3+ cations. 7,9,10 La 3 CuGaSe 7 contains interesting isolated [CuSe 3 ] 4− pyramids and [GaSe 4 ] 5− tetrahedra and exhibits interesting centrosymmetric photo-response behaviour.…”

Rare-earth-based chalcogenides and their derivatives: an encouraging IR nonlinear optical material candidate

“…In order to better illustrate the advantages of RE-based chalcogenide compounds and address the challenges in this field, this paper provides detailed explanations for 85 representative examples out of over 400 NCS compounds. 68–187 These examples are categorized into four groups based on the various asymmetric building motifs: (1) RE-based chalcogenides containing tetrahedral motifs; (2) RE-based chalcogenides containing lone-pair-electron motifs; (3) RE-based chalcogenides containing [BS 3 ] and [P 2 Q 6 ] motifs; and (4) RE-based chalcohalides and oxychalcogenides. Finally, the conclusions and perspectives for RE-based chalcogenides and their derivatives are provided for further exploration.…”