BS3Sm, orthorhombic, Pna21 (no. 33), a = 7.3657(5) A, b = 6.0272(2) A, c = 8.8004(6) A, V = 390.69 A 3 , Z =4 , R(F 2 ) = 0.068, R(P) = 0.013, T = 295 K. Source of material Sm[BS3] was prepared by using a high-temperature highpressure route. Molar ratios o f1:3:6 ofsamarium (powder, ChemPur, 99.9 %), amorphous boron (ABCR, 99 %) and sulfur (Alfa Aesar, 99.9995 %, sublimed under vacuum to reduce contamination by oxygen below 1 %) were used. Molar ratios corresponding to the chemical composition of the title compound did not yield sufficiently pure materials. The educts were ground and filled into the assembly of the octahedral high pressure setup, under argon atmosphere of a glove box. Hexagonal boron nitride was used as the crucible material. High pressure conditions were achievedbyusingahydraulicuniaxialpress[1].Forceredistribution was accomplished by a Walker-type module and MgO octahedra with an edge length of 18 mm [2]. Elevated temperatures were realized by resistive heating of graphite tubes enclosing the sample crucible. For the synthesis of Sm[BS3], the assembly was heated to 1673 K and compressed to 3 GPa for 5 h. Afterthepressureandheatingcycle,thearrangementwasinstantaneously removed and transferred into a glove box where the sample was isolated from the crucible. No indications of a reactionbetweenthesampleandthecruciblematerialwereobserved. The air- and humidity-sensitive compound Sm[BS3] was obtained as a red-brown polycrystalline material. Experimental details X-ray powder diffraction data were collected on a STOE StadiPMPdiffractometerinDebye-Scherrergeometry.TheGSASsoftware package [3] was used for the Rietveld refinements. The unit cellparametersatroomtemperatureweredeterminedfromX-ray powder diffraction data (CuK1), using LaB6(a= 4.15692(1) A) as internal standard, and refined by least squares refinements usingtheWinCSDprogram[4].Thepositionoftheboronatomwas restrainedtobenearthecentreofgravityofthesulfuratomsofthe [BS3] 3– unit. The isotropic displacement parameters of the sulfur atoms were constrained to be equal and the corresponding parameter of the boron site was constrained to be equal to that of the attached sulfur atoms. Discussion The new RE thioborate Sm[BS3], obtained as a product of the high-pressure high-temperature experiments, is an isotype of the RE[BS3] series (RE= Ce, Pr, Nd) [5,6]. The crystal structure was refinedfromX-raypowderdiffractiondatausingtheRietveldrefinement method [7]. The crystal structure of Sm[BS3] is characterized by corrugated kagome nets formed by sulfur atoms, with the boron atoms occupying every second triangle, while Sm cations center the large hexagons. The corrugated nets are stacked along [100] according to the sequence ABAB. The coordination sphereofSmisformedbyninesulfurspeciesoriginatingfromsix neighboring thioborate units. Three of the [BS3] 3– units act as bidentate ligands, while the other three are in monodentate func