Tricyanidoferrates(−IV) and ruthenates(−IV) with non‐innocent cyanido ligands

Exceptionally electron-rich, nearly trigonal-planar tricyanidometalate anions [Fe(CN)(3)](7-) and [Ru(CN)(3)](7-) were stabilized in LiSr3[Fe(CN)(3)] and AE(3.5)[M(CN)(3)] (AE=Sr, Ba; M=Fe, Ru). They are the first examples of group 8 elements with the oxidation state of -IV. Microcrystalline powders were obtained by a solid-state route, single crystals from alkali metal flux. While LiSr3[Fe(CN)(3)] crystallizes in P6(3)/m, the polar space group P6(3) with three-fold cell volume for AE(3.5)[M(CN)(3)] is confirmed by second harmonic generation. X-ray diffraction, IR and Raman spectroscopy reveal longer C-N distances (124-128 pm) and much lower stretching frequencies (1484-1634 cm(-1)) than in classical cyanidometalates. Weak C-N bonds in combination with strong M-C pi-bonding is a scheme also known for carbonylmetalates. Instead of the formal notation [Fe-IV(CN-)(3)](7-), quantum chemical calculations reveal non-innocent intermediate-valent CN1.67- ligands and a closed-shell d(10) configuration for Fe, that is, Fe2-

Cs7Nd11(SeO3)(12)Cl-16: first noncentrosymmetric structure among alkaline-metal lanthanide selenite halides

Cs7Nd11(SeO3)(12)Cl-16, the complex selenite chloride of cesium and neodymium, was synthesized in the NdOCl-SeO2-CsCl system. The compound has been characterized using single-crystal X-ray diffraction, electron diffraction, transmission electron microscopy, luminescence spectroscopy, and second-harmonic-generation techniques. Cs7Nd11(SeO3)(12)Cl-16 crystallizes in an orthorhombic unit cell with a = 15.911(1) angstrom, b = 15.951(1) angstrom, and c = 25.860(1) angstrom and a noncentrosymmetric space group Pna2(1) (No. 33). The crystal structure of Cs7Nd11(SeO3)(12)Cl-16 can be represented as a stacking of Cs7Nd11(SeO3)(12) lamellas and CsCl-like layers. Because of the layered nature of the Cs7Nd11(SeO3)(12)Cl-16 structure, it features numerous planar defects originating from occasionally missing the CsCl-like layer and violating the perfect stacking of the Cs7Nd11(SeO3)(12)Cl-16 lamellas. Cs7Nd11(SeO3)(12)Cl-16 represents the first example of a noncentrosymmetric structure among alkaline-metal lanthanide selenite halides. Cs7Nd11(SeO3)(12)Cl-16 demonstrates luminescence emission in the near-IR region with reduced efficiency due to a high concentration of Nd3+ ions causing nonradiative cross-relaxation

Two New Arsenides, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, With a New Filled Variety of the BaHg₁₁ Structure

Two new ternary arsenides, namely, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, were synthesized from elements at 800 °C. Their crystal structure represents a new filled version of the BaHg₁₁ motif with cubic voids alternately occupied by Eu­(Sr) and As atoms, resulting in a 2 × 2 × 2 superstructure of the aristotype: space group <i>Fm</i>3̅<i>m</i>, <i>a</i> = 16.6707(2) Å and 16.7467(2) Å, respectively. The Eu derivative exhibits ferromagnetic ordering below 17.5 K. In agreement with band structure calculations both compounds are metals, exhibiting relatively low thermopower, but high electrical and low thermal conductivity

Two New Arsenides, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, With a New Filled Variety of the BaHg₁₁ Structure

Two new ternary arsenides, namely, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, were synthesized from elements at 800 °C. Their crystal structure represents a new filled version of the BaHg₁₁ motif with cubic voids alternately occupied by Eu­(Sr) and As atoms, resulting in a 2 × 2 × 2 superstructure of the aristotype: space group <i>Fm</i>3̅<i>m</i>, <i>a</i> = 16.6707(2) Å and 16.7467(2) Å, respectively. The Eu derivative exhibits ferromagnetic ordering below 17.5 K. In agreement with band structure calculations both compounds are metals, exhibiting relatively low thermopower, but high electrical and low thermal conductivity

Two New Arsenides, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, With a New Filled Variety of the BaHg₁₁ Structure

Two new ternary arsenides, namely, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, were synthesized from elements at 800 °C. Their crystal structure represents a new filled version of the BaHg₁₁ motif with cubic voids alternately occupied by Eu­(Sr) and As atoms, resulting in a 2 × 2 × 2 superstructure of the aristotype: space group <i>Fm</i>3̅<i>m</i>, <i>a</i> = 16.6707(2) Å and 16.7467(2) Å, respectively. The Eu derivative exhibits ferromagnetic ordering below 17.5 K. In agreement with band structure calculations both compounds are metals, exhibiting relatively low thermopower, but high electrical and low thermal conductivity