Insight into framework destruction in ultramarine pigments

Eleonora Del Federico, Wolfgang Shöfberger, Johannes Schelvis, Sofia Kapetanaki, Lindsey Tyne, Alexej Jerschow

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


We report key evidence on the framework destruction in ultramarine pigments upon color fading. Experiments on faded pigments in a fresco painting environment reveal that the paramagnetic chromophores are set free via sodalite framework destruction and are subsequently degraded. Fading in acidic media produces similar results, although a larger number of β-cages appear to be destroyed, and H2S is released. The findings are further supported by studies on natural and synthetic ultramarine pigments of various shades via solid-state resonance-Raman spectroscopy, colorimentry, and solid-state 29Si and 27Al NMR spectroscopy. NMR parameters are shown to correlate well with the intensities of Raman signals corresponding to the S3-. chromophores. A further correlation is established between the colorimetric parameters, L* (lightness) and C* (chroma), and the paramagnetic shift and paramagnetic linebroadening in NMR spectra for both 27Al and 29Si.

Original languageEnglish
Pages (from-to)1270-1276
Number of pages7
JournalInorganic Chemistry
Issue number3
StatePublished - 6 Feb 2006


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