Three New Phases in the K/Cu/Th/S System:  KCuThS₃, K₂Cu₂ThS₄, and K₃Cu₃Th₂S₇

Abstract

Synthetic exploration of K/Cu/Th/S quaternary phase space has yielded three new compounds: KCuThS3 (I), K2Cu2ThS4 (II), and K3Cu3Th2S7 (III). All three phases are semiconductors with optical band gaps of 2.95, 2.17, and 2.49 eV(I-III). Compound I crystallizes in the orthorhombic space group Cmcm with a = 4.076(1) A, b = 13.864(4) A, and c = 10.541(3) A. Compound II crystallizes in the monoclinic space group C2/m with a = 14.522(1) A, b = 4.026(3) A, and c = 7.566(6) A; beta = 109.949(1) degrees . Compound III crystallizes in orthorhombic space group Pbcn with a = 4.051(2) A, b = 14.023(8) A, and c = 24.633(13) A. The compounds are all layered materials, with each layer composed of threads of edge-sharing ThS6 octahedra bridged by CuS4 tetrahedral threads of varying dimension. The layers are separated by well-ordered potassium ions. The relatively wide range of optical band gaps is attributed to the extent of the CuS4 motifs. As the dimension of the CuS4 chains increases, band gaps decrease in the series. All materials were characterized by single-crystal X-ray diffraction, microprobe chemical analysis, and diffuse reflectance spectroscopy (NIR-UV).

Synthesis, structural and spectroscopic properties of orthorhombic compounds BaLnCuS3 (Ln = Pr, Sm)

“…However, BaSmCuS3 peaks were indexed by an orthorhombic cell (space group Cmcm) with parameters close to those of KThCuS3 [36]. Besides, in this sample, a small amount (~5% wt.)…”

Synthesis, crystal structure, optical, and electronic study of the new ternary thorium selenide Ba3ThSe3(Se2)2

“…The few known quaternary thorium chalcogenides include ACuThQ 3 (A = K, Cs, Tl; Q = S, Se) [23][24][25][26], Ba 2 Cu 2 ThS 5 [27], Ba 2 Cu 2 ThSe 5 [28], K 2 Cu 2 ThS 4 [23], K 3 Cu 3 Th 2 S 7 [23], KThSb 2 Se 6 [29], and Ba 2 CrThTe 7 [30].…”

Syntheses, crystal structures, and electronic properties of Ba 8 Si 2 US 14 and Ba 8 SiFeUS 14

“…Among these compounds, the actinide (An) chalcogenides have also been extensively studied because of the interesting properties of the f orbitals and their potential interaction with d elements in multinary M/AnQ. Among these, we can cite: AMAnQ 3 (A ¼ alkali metal) [6e8], A 6 Cu 12 U 2 S 15 [9], Tl 3 Cu 4 USe 6 [10], KCuThS 3 , K 2 Cu 2 ThS 4 , K 3 Cu 3 Th 2 S 7 [11], K 2 Cu 3 US 5 [12], CsTiUTe 5 [13], Ba 2 Cu 2 AnS 5 [14,15], Ba 9 Ag 10 U 4 S 24 [16], Ba 3 MUS 6 (M ¼ Ba, Fe, Ag) [17], Ba 4 Cr 2 US 9 [18], and Ba 3 Hg 3 U 3 S 18 [19]. These compounds are mainly obtained through solid-state reactions using flux methods [20] or by direct combination of elements.…”