Ultramarine pigments have sulphur-based chromophores
in an aluminosilicate framework. This book describes
the synthesis of ultramarine blue from fly ash (a
predominantly aluminosilicate waste product of coal
combustion). Microscopy shows that sulphur has a
structure-directing effect and facilitates the
formation of the zeolite-like structures of
ultramarine pigments. The identities of the
chromophores are a source of debate and this work
contributes to the debate, by modelling several
candidate species for the yellow, blue and red
species in ultramarine pigments. For sulphur chains
with two...