Department of Chemistry and Food Chemistry, Technische Universität Dresden, 01062 Dresden, Germany.
Inorg Chem. 2012 Jan 2;51(1):282-9. doi: 10.1021/ic201639f. Epub 2011 Dec 2.
Dark red crystals of Y₈S(14.8), Tb₈S(14.8), Dy₈S(14.9), and Ho₈S(14.9) have been obtained following different reaction routes. The isostructural title compounds adopt the Gd₈Se₁₅ type, a 24-fold superstructure of the ZrSSi-type and can be described in space group A112 (non standard setting of C121, no. 5) with lattice parameter of a = 11.505(1) Å, b = 15.385(1) Å, c = 15.726(1) Å, and γ = 90.21(2)° for Y₈S(15-x); a = 11.660(1) Å, b = 15.468(2) Å, c = 15.844(2) Å, and γ = 90.19(2)° for Tb₈S(15-x); a = 11.584(1) Å, b = 15.340(2) Å, c = 15.789(2) Å, and γ = 90.34(2)° for Dy₈S(15-x); and a = 11.538(1) Å, b = 15.288(2) Å, c = 15.740(2) Å, and γ = 90.23(1)° for Ho₈S(15-x), respectively. The structure consists of an alternating stacking of puckered [RES] (RE, rare-earth metals) double slabs and planar sulfur layers along [001]. The planar sulfur layers have a complex arrangement of S₂²⁻ dinuclear dianions, isolated S²⁻ ions, and vacancies. All compounds contain trivalent rare-earth metal ions, for Tb₈S(15-x) and Dy₈S(15-x) antiferromagnetic order was found at T(N) = 5.4(2) K and 3.8(1) K, respectively. Short wavelength cutoff optical band gaps of 1.6 to 1.7 eV were determined.
已经通过不同的反应途径获得了 Y₈S(14.8)、Tb₈S(14.8)、Dy₈S(14.9) 和 Ho₈S(14.9) 的深红色晶体。这些同构的标题化合物采用了 Gd₈Se₁₅ 型结构，是 ZrSSi 型的 24 倍超结构，可在空间群 A112（非标准设置的 C121，编号 5）中描述，晶格参数为 a = 11.505(1) Å，b = 15.385(1) Å，c = 15.726(1) Å，γ = 90.21(2)°，适用于 Y₈S(15-x)；a = 11.660(1) Å，b = 15.468(2) Å，c = 15.844(2) Å，γ = 90.19(2)°，适用于 Tb₈S(15-x)；a = 11.584(1) Å，b = 15.340(2) Å，c = 15.789(2) Å，γ = 90.34(2)°，适用于 Dy₈S(15-x)；a = 11.538(1) Å，b = 15.288(2) Å，c = 15.740(2) Å，γ = 90.23(1)°，适用于 Ho₈S(15-x)。结构由交替堆叠的褶皱[RES]（RE，稀土金属）双片和沿[001]的平面硫层组成。平面硫层具有复杂的 S₂²⁻双核二阴离子、孤立的 S²⁻离子和空位排列。所有化合物均含有三价稀土金属离子，对于 Tb₈S(15-x)和 Dy₈S(15-x)，发现反铁磁有序在 T(N) = 5.4(2) K 和 3.8(1) K 下存在。确定了 1.6 到 1.7 eV 的短波长截止光学带隙。
