  Susceptibility, ESR and magnetization measurements have been performed on si
ngle crystals of an S=1 bond alternating chain compound: [Ni(333-tet)(\mu-NO
_2)](ClO_4) (333-tet = N,N'-bis(3-aminopropyl)propane-1,3-diamine) and the c
ompound doped with a small amount of Zn. We observed an anomalous angular de
pendence in the Zn-doped sample. These behaviors are well explained by the m
odel based on the VBS picture for the singlet-dimer phase. The picture impli es
that the free spins of S=1 with a positive single-ion anisotropy are indu ced
at the edges of the chains without forming the singlet-dimer.
