Endohedral N @ C-60 (atomic nitrogen inside C-60) is produced by ion i
mplantation. Two different production methods are employed: Kaufman io
n source and glow discharge. After the bombarded material is dissolved
in toluene or CS2 and is filtered, several milligrams of C-60 contain
ing N @ C-60 in a concentration of 10(-4) to 10(-5) are obtained. N @
C-60 gives a very clear hyperfine-split electron paramagnetic resonanc
e signal. The most prominent features of N @ C-60 are: (i) Nitrogen in
C-60 keeps its atomic electronic configuration and occupies the on-ce
nter position. (ii) N @ C-60 is stable at ambient conditions, the ther
mal instability starts at 260 degrees C. (iii) The complex survives ex
ohedral addition reactions and is a sensitive detector of cage distort
ions caused by addends. (iv) C-60 and N @ C-60 exhibit slightly differ
ent retention times in column chromatography, thus permitting an enric
hment of N @ C-60 by this method.