Beiträge zum system BaONiO

Ab-initio Band Structure Calculations and 61 Ni-Mössbauer Studies of BaNiO2 , BaNiO3 and CaNiN

“…It might be that this finding is caused by the approximation for the exchange-correlation potential which also predicts no optical band gap for NiO. For NiO it is demonstrated that this incorrect result can be traced back to the approximate correlation potential and the self energy term [26], Nevertheless it should be mentioned that the electrical resistivity of BaNi0 2 is by a factor of 2000 smaller than that of BaNi0 3 [22],…”

“…1) is an isotype of the YCoC type structure [19] and also isotype to SrLiN [20]. The crystal structure is tetragonal (Space group P4 2 /mmc, a = 358.09 (2) In the crystal structure of BaNi0 2 [21][22][23] (Fig. 2) nickel is in a square-planar coordination by oxygen.…”

“…2) nickel is in a square-planar coordination by oxygen. [22].) The nickel-oxygen squares share opposite edges and form puckered chains which run along the crystallographic c-axis.…”

“…The intensity of the slightly broadened line corresponds to an absorber thickness of t eff = 0.78(5) from which a Lamb-Mössbauer factor of 0.11 (1) can be deduced. From magnetic susceptibility measurements it is known that BaNi0 3 is diamagnetic [22], and therefore the unresolved splitting must be caused by a quadrupole splitting equivalent to an EFG q = ± 3.6(2.0) • 10 21 VITT 2 . With the given statistics, the relatively small splitting did neither allow the determination of the sign of q nor of rj.…”

High-Pressure Synthesis and Structures of New Barium Chromium Sulfides, BaCr4S7 and Ba2Cr5S10, with New Type Face-Sharing CrS6 Structure Units

“…17 We have prepared two chromium sulfides with 1-D structures, Ba 3 CrS 5 , and Ba 3 Cr 2 S 6 at high pressures and high temperatures. 1 These sulfides, having structures that are closely related to BaNiO 3 , [18][19][20] structure and can be prepared only by high-pressure synthesis method. Reaction conditions of the high-pressure synthesis method are completely different from any other conventional ones using evacuated ampoules or floating CS 2 or H 2 S gases.…”