Single crystals of BaV13O18 (V+2.62) containing a small amount of Cr (about
7% of vanadium sites) were prepared by heating a mixture of BaCO3, V2O5, V
, and Cr powders at 1973 K for 40 h in flowing Ar. Crystal structure analys
is using single-crystal data (Rigaku AFC7R, 4037 reflections) showed that t
he BaV13O18 has a rhombohedral unit cell with a(h) = 12.621(5) Angstrom, C-
h = 7.020(5) Angstrom, v = 968.4(9) Angstrom (3), Z = 3, D-cal = 5.595 g.cm
(-3) and space group R-3 (R-1 = 1.96%, wR(2) = 3.60%, S = 1.095), In the st
ructure, Be and O formed a cubic close-packed arrangement and every V was c
oordinated by six O, BaV13O18 has three kinds of vanadium environments: one
almost regular octahedral site and two distorted octahedral sites. VO6 oct
ahedra share their corners and edges, (C) 2001 Academic Press.