Mixed Tellurides Ni3-xGaTe2 (0 <= x <= 0.65): Crystal and Electronic Structures, Properties, and Nickel Deficiency Effects on Vacancy Ordering

作者：Isaeva Anna A^*; Makarevich Olga N; Kuznetsov Alexey N; Doert Thomas; Abakumov Artem M; Van Tendeloo Gustaaf

来源：European Journal of Inorganic Chemistry, 2010, 2010(9): 1395-1404.

DOI：10.1002/ejic.200901027

• Nickel chalcogenides
• Subvalent compounds
• Electron microscopy
• NiAs derivatives
• Layered compounds

The Ni3-xGaTe2 series of compounds (0 <= x <= 0.65) was synthesized by a high-temperature ceramic technique at 750 degrees C. Crystal structures of three compounds in the series were determined by X-ray powder diffraction: Ni2.98(1)GaTe2 (R-1 = 0.042, R-p = 0.023, R-wp = 0.035), Ni2.79(1)GaTe2 (R-1 = 0.053, R-p = 0.028, R-wp = 0.039), Ni2.58(1)GaTe2 (R-1 = 0.081, R-p = 0.037, R-wp = 0.056); the structures were verified by electron diffraction and, for the former compound, high-resolution electron microscopy. The compounds crystallize in a hexagonal lattice with P6(3)/mmc, and the structures can be regarded as a hexagonal close-packed array with a -Ga-Te-Te- stacking sequence. The octahedral and trigonal bipyramidal voids in the hcp structure are selectively filled with Ni atoms to form one entirely occupied and two partially occupied sites, thus allowing variations in the nickel content in the series of compounds Ni3-xGaTe2 (0 <= x <= 0.65). A superstructure with a(sup) = 2a(sub) (P6(3)/mmc) has been identified for Ni3-xGaTe2 (0.5 <= x <= 0.65) by electron diffraction. Real-space, high-resolution images confirm an ordering of Ni atoms and vacancies in the ab plane. Quantum-chemical calculations performed for Ni3-xGaTe2 (x = 0, 0.25, 0.75, 1) suggest anisotropic metallic conductivity and Pauli paramagnetic behavior that are experimentally confirmed for Ni3GaTe2.

• 出版日期2010-3