The ternary chalcogenide Nb3Pd0.72Se7has been synthesized and its structure has been established through single-crystal X-ray measurements. The compound crystallizes in space group C32h—C2/m of the monoclinic system with four formula units in a cell of dimensions a = 12.803 (2) A, b = 3.413 (1) Å, c = 21.058 (2) A, and β = 95.47 (1)°. The structure is a new laminar type that consists of layers of formula 2∞[Nb6PdSe14]. Between these layers additional Pd atoms statistically occupy (43%) a rhombic site. Occurrence of the layers 2∞[Nb6PdSe14] and the known layers 2∞[Nb4PdSe10] and 2∞[Nb2PdSe6] allows formulation of the set of layers 2∞[Nb2nPdSe4n+2], where n = 1, 2, and 3 have thus far been observed. This formulation includes the compositional behavior as well as the structural pattern that evolves with a serial change in the index n. This structural pattern is extended with comparisons between this set and the structural types NbSe2, NbSe2, Nb2Pd3Se8, and Co2Ta4PdSe12. From these comparisons, structural details, valence descriptions, and physical properties a model for the electronic structure of the ternary phases that contain Nb, Pd, and Se atoms is proposed.
ASJC Scopus subject areas
- Colloid and Surface Chemistry