Marten G. Barker, Alexander J. Blake, Duncan H. Gregory, Daniel J. Siddons, Susan E. Smith, Peter P. Edwards and Thomas A. Hamor
New compounds in which nickel is substituted for lithium in lithium nitride show evidence of high lithium vacancy concentrations and an ordering of these vacancies to form new structural variants.
2m(no.
189), a= 6.475(3), c= 3.555(2)Å, Z= 1, V= 129.1(3)Å3, Dc=
3.253 g cm–3, µ= 10.67 mm–1. 868 reflections measured at 293(2) K,
109 independent (Rint= 0.0712). Data collected on a Rigaku R-Axis II
area detector diffractometer with graphite monochromated Mo-Kα
radiation (λ= 0.71073 Å). The structure was solved by direct methods
with SHELXS-86a, and refined by least squares within SHELXL-93.bw= 1/[σ2(Fo2)+(0.040P)2+ 0.59P] where P=(Fo2+ 2Fc2)/3 R1 =
0.0351, wR2 = 0.0884; LiNiN, M= 79.66, hexagonal space group P
m2 (no.187), a=
3.758(1), c= 3.540(1)Å, Z= 1, V= 43.30(2)Å3, Dc= 3.055 g cm–3.
µ= 10.606 mm–1, 1440 reflections measured at 297(2) K, 171
independent (Rint= 0.024). Data collected on a Stadi-4 diffractometer
with Mo-Kα radiation (λ= 0.71073 Å). The structure was solved by
direct methods with SHELXL-86a and refined by least squares within
SHELXL-93.bw= 1/[σ2(Fo2)+(0.0584 P)2] where P=(Fo2+ 2Fc2)/3.
R1 = 0.0374, wR2 = 0.0803. (a)G. M. Sheldrick,
Acta Crystallogr., Sect. A,
1990,
46,
467;
(b)G. M. Sheldrick,
SHELXL-93, Program for Crystal Structure Refinement, University of Gottingen, Gottingen, Germany,
1993 Search PubMed; CCDC 182/1262. See http://www.rsc.org/suppdata/cc/1999/1187/ for crystallographic files in
.cif.format.
m2 model are the partial occupancy of the interplane site by Li
(Li:Ni = 0.23:0.87) and disordered Li vacancies in the Li-N planes
giving a Li(2) site partial occupancy (0.55).