This volume C 3, as a part of the Gmelin "Thorium" Handbook, Series C,
describes the thorium-nitrogen compounds. Included are compounds both of
technological importance like the nitrides and the nitrates and those of
merely scientific interest, such as amides and related compounds.
However, due to the decreasing technical importance of the nuclear
thorium fuel cycle, especially with the advanced fuels like the nitride
ThN, in recent years, the thorium compounds with nitrogen have been
investigated much less extensively than the correspond- ing uranium
compounds. In order to have the data for the Th-N-X systems accumulated
in one specific volume, the decision was made to publish this volume
without incorporating other Th systems. ThN is the compound with the
lowest N: Th ratio. In addition to its (former) nuclear interest due to
its thermal and radiation stability, it has many very interesting
physicochemical properties. Thorium nitrate, the other well-investigated
compound, is of importance because it is (in the form of an adduct with
tri-n-butylphosphate) the extracted compound when burnt-up thorium fuels
are reprocessed. Despite the wealth of accumulated data on the chemical
and physicochemical properties of the compounds discussed, the knowledge
of the compounds and of the systems is far from satisfactory - it must
be deepened and improved in further studies. I would like to thank the
competent authors for their critical contributions as well as the
Gmelin-Institute for the excellent cooperation provided, especially
Prof. Dr. Fluck and Dr. Keim, the editor-in-chief of this volume.