Syntheses, Crystal and Electronic Structures, and Physical Properties of Two Quaternary Chalcogenides: La4FeSb2Q10 (Q = S, Se)

摘要: Two new quaternary chalcogenides, La4FeSb2S10 and La4FeSb2Se10, have been synthesized from the stoichiometric mixture of elements by solid-state reactions at 1100 °C. The compounds crystallize in orthorhombic space group Pbcm with a = 15.066(4) A, b 7.590(2) c 13.341(4) Z 4 15.596(5) 7.869(2) 13.960(4) 4, respectively. These structures represent an unique three-dimensional network, which SbQ3 trigonal pyramids (Sb−S < 2.60 Sb−Se 2.80 A) are connected via relatively weak Sb−Q bond ≈ 2.90 3.00 novel teeter-totter (SbQ4)n chain motif. theoretical studies confirm bonding interactions within such chains. Their optical band gaps measured to be 1.00 0.85 eV. At room temperature, their electrical conductivities about 10−4 S/cm. Both display antiferromagnetic between Fe centers, effective magnetic moments 5.25 6.17 μB,