A Challenge toward Novel Quaternary Sulfides SrLnCuS3 (Ln = La, Nd, Tm): Unraveling Synthetic Pathways, Structures and Properties

Abstract

We report on the novel heterometallic quaternary sulfides SrLnCuS3 (Ln = La, Nd, Tm), obtained as both single crystals and powdered samples. The structures of both the single crystal and powdered samples of SrLaCuS3 and SrNdCuS3 belong to the orthorhombic space group Pnma but are of different structural types, while both samples of SrTmCuS3 crystallize in the orthorhombic space group Cmcm with the structural type KZrCuS3. Three-dimensional crystal structures of SrLaCuS3 and SrNdCuS3 are formed from the (Sr/Ln)S7 capped trigonal prisms and CuS4 tetrahedra. In SrLaCuS3, alternating 2D layers are stacked, while the main backbone of the structure of SrNdCuS3 is a polymeric 3D framework [(Sr/Ln)S7]n, strengthened by 1D polymeric chains (CuS4)n with 1D channels, filled by the other Sr2+/Ln3+ cations, which, in turn, form 1D dimeric ribbons. A 3D crystal structure of SrTmCuS3 is constructed from the SrS6 trigonal prisms, TmS6 octahedra and CuS4 tetrahedra. The latter two polyhedra are packed together into 2D layers, which are separated by 1D chains (SrS6)n and 1D free channels. In both crystal structures of SrLaCuS3 obtained in this work, the crystallographic positions of strontium and lanthanum were partially mixed, while only in the structure of SrNdCuS3, solved from the powder X-ray diffraction data, were the crystallographic positions of strontium and neodymium partially mixed. Band gaps of SrLnCuS3 (Ln = La, Nd, Tm) were found to be 1.86, 1.94 and 2.57 eV, respectively. Both SrNdCuS3 and SrTmCuS3 were found to be paramagnetic at 20–300 K, with the experimental magnetic characteristics being in good agreement with the corresponding calculated parameters.

Magnetic, Optical, and Thermic Properties of SrLnCuSe3 (Ln = Dy, Ho, Er, Tm) Compounds

“…The experimental effective magnetic moment is equal to 3.611 µB and 7.378 µB for complex Nd and Tm sulfides, respectively. The calculated effective magnetic moments of Nd 3+ and Tm 3+ ions (3.618 µB and 7.561 µB, respectively) coincide well enough with their experimental values, thus confirming that the Sr 2+ ions exist in a non-magnetic state [12]. The influence of Ln 3+ and Cu + cations on the magnetic properties of SrLnCuSe 3 compounds can be traced by replacing the magnetic cation Eu 2+ (4f 7 5d 0 6s 0 ) in the series of complex selenide compounds with a non-magnetic cation Sr 2+ (5s 0 ).…”

“…As for the corresponding Curie constants, the deviation is twice as large due to the quadratic dependence with respect to the values of effective magnetic moments [5]. SrNdCuS 3 and SrTmCuS 3 are paramagnetic at 296 K [12]. The experimental effective magnetic moment is equal to 3.611 µB and 7.378 µB for complex Nd and Tm sulfides, respectively.…”

Elucidating a Series of the Quaternary Selenides BaRECuSe3 with a Rich Library of Optical Properties

“…For BaRECuSe 3 , as mentioned above, the change of a space group is observed on the Ce/Nd boundary (Figure ). Thus, an increase in the radius of the M 2+ cation or the radius of the chalcogenide anion Ch 2– , while keeping the rest of the composition unchanged, leads to an earlier formation of a symmetric structure ( Cmcm symmetry) in MRECuCh 3 (M = Eu, Sr and Ba; Ch = S, Se and Te). ,− ,− ,− …”

Synthesis, structures and magnetic properties of the Eu-based quaternary tellurides EuGdCuTe3and EuLuCuTe3

“…During the last decade, several synthetic approaches toward chalcogenides have been developed, of which the flux method has been found to be one of the most efficient both to avoid the formation of impurities and to significantly decrease the synthetic time. 2,4,6,7,15,25,38 With all this in mind, in this work we have focused on the synthesis of EuGdCuTe 3 and EuLuCuTe 3 as well as studying their crystal structures and magnetic properties. Both compounds are the first obtained and characterized examples within the series of quaternary tellurides EuRECuTe 3 .…”

“…During the last decade, several synthetic approaches toward chalcogenides have been developed, of which the flux method has been found to be one of the most efficient both to avoid the formation of impurities and to significantly decrease the synthetic time. 2,4,6,7,15,25,38…”