Volume II/26 supplements the previous compilations II/l, II/9 and II/17
of the magnetic properties of free radicals which were published in
1965, 1977-1980 and 1986-90. In the form of books and CD ROM it covers
the literature from about 1985 to 2001. Due to the still rapid growth of
the field and the necessary inclusion of new subjects the volume is
divided into subvolumes which will appear in fast succession. Together
with the earlier publications volume II/26 offers an up-to-date and
comprehensive survey and collection of structures and data on the
important chemical intermediates, namely radicals, polyradicals and
related species such as carbenes, nitrenes, etc. As before the species
have been grouped according to chemical aspects. The contents of the
individual subvolumes are indicated on the inside of the front covers.
For each group of substances the literature has been compiled and
extracted by experts in the fields. A small overlap between the chapters
is intentional and allows a maximum of coherence and comprehensiveness
of the display. For the reader's convenience an index of substances
follows in the last subvolume. Data retrieval is also facilitated by
helpful links in the CD ROM version. We wish to thank all the authors
for their careful and experienced work and the most agreeable
cooperation, the Landolt- Börnstein office, especially Mrs. A.