In:
Zeitschrift für Naturforschung A, Walter de Gruyter GmbH, Vol. 51, No. 5-6 ( 1996-6-1), p. 515-526
Abstract:
The electron density distribution of the nickel compounds BaNiO 2 , BaNiO 3 and CaNiN has been investigated experimentally by 61 Ni Mössbauer spectroscopy and theoretically by band structure calculations using the FP-LMTO (Full Potential Linear Muffin-Tin Orbital) method. For all compounds good agreement is found between the experimental and theoretical values of the electric field gradient q exp. and q theor. at the nickel site. BaNiO 2 contains nickel in a square-planar coordination forming puckered chains of edge-sharing NiO 4 squares. |q| at nickel is large: q exp = - 15.7(1.5) • 10 21 Vm -2 and q theor. = - 15.59 • 10 21 Vm -2 . The principal axis z is perpendicular to the NiO 4 squares. The crystal structure of BaNiO 3 contains face-sharing chains of NiO 6 octahedra. In BaNiO 3 q(Ni) is small: q exp. = ± 3.6(2.0) • 10 21 Vm -2 and q theor. = - 1.86 • 10 21 Vm -2 . Because of the small broadening of the Mössbauer resonance line the sign of q could not be determined experimentally. The nitridoniccolate CaNiN contains infinite linear chains 1 ∞ [NiN 2/2 ] which run perpendicular to the c axis. Unexpectedly, |q(Ni)| in CaNiN is small: q exp. = 0.0 (2.0) • 10 21 Vm -2 and q theor. = - 3.05 • 10 21 Vm -2 . Again the sign of q(Ni) could not be determined experimentally. It is found theoretically that the small value of q(Ni) is caused by severe cancellation between σ and π contributions.
Type of Medium:
Online Resource
ISSN:
1865-7109
,
0932-0784
DOI:
10.1515/zna-1996-5-626
Language:
English
Publisher:
Walter de Gruyter GmbH
Publication Date:
1996
detail.hit.zdb_id:
2079610-9
detail.hit.zdb_id:
124634-3
detail.hit.zdb_id:
124633-1
detail.hit.zdb_id:
2767412-5
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