Crystal Structure and Physical Properties of a New CuTi₂S₄ Modification in Comparison to the Thiospinel

Abstract

A new modification of CuTi(2)S(4) was prepared from the elements at 425 degrees C. It crystallizes in the rhombohedral space group Rm, with lattice parameters of a = 7.0242(4) A, c = 34.834(4) A, and V = 1488.4(2) A(3) (Z = 12). Two topologically different interlayer regions exist between the close-packed S layers that alternate along the c axis: one comprises both Cu (in tetrahedral voids) and Ti atoms (in octahedral voids), and the second exclusively Ti atoms (again in octahedral voids). In contrast to the known modification, the spinel, Cu-Ti interactions of 2.88 A occur that have bonding character according to the electronic structure calculations. Both CuTi(2)S(4) modifications are metallic Pauli paramagnets due to Ti d contributions. The Pauli susceptibility of the Rm form is larger than that of the thiospinel in quantitative agreement with the LMTO-ASA band structure calculations. The irreversible transformation to the spinel takes place at temperatures above 450 degrees C.

Crystal structure, electronic structure and thermoelectric properties of Cu4Sn7S16

“…The Cu-S distances range from 2.224(1) to 2.668(4)Å, which are comparable to those in the ternary compounds Cu 2 GeS 3 (2.292(2)-2.354(3)Å) [18] and CuTi 2 S 4 (2.243(2)-2.284(2)Å) [19]. The Sn-S bond distances range from 2.512(1) to 2.596(2)Å.…”

Transport, magnetic, thermal and structural properties of the spinel compound CuTi2S4

“…Considering the previous reports [1,[7][8][9][10]19], the valence state of Cu is closer to Cu 1+ . That is, the 3d bands of Cu exist below the Fermi level and the bands near the Fermi level are dominantly of Ti 3d character.…”

Thermal stability of the layered modification of Cu0.5ZrTe2 in the temperature range 25–900 °C

“…1), which belong to the Cu 7 Te 4 phase (Baranova, 1967) and to the defective rhombohedral phase CuZr 2 Te 4 , which is observed for the first time. The isostructural analog of the latter CuTi 2 S 4 phase was observed in Soheilnia et al (2004). To simplify the notation of these nonstoichiometric phases, we designated the layered phase as Cu x ZrSe 2 and the rhombohedral phase as CuZr 2 Se 4 .…”