Cobalt yellow

About the chemical structure:

Chemical name:	potassium cobaltinitrite
Formula:	K3[Co(NO2)6] · H2O
Refractive index:	n/a

Color:

Color Index (C.I.)

PY 40

How can you identify Cobalt yellow?

Imaging:

UVF: no

IRFC: blue

OM: at high magnification, tiny crystals and crystalline clusters appear.

Analytics:

It's identified by means of FTIR and Raman.

Raman spectra: University College London;

FTIR spectra: IRUG

Usage and handling:

Permanence:	Toxicity:
Lightfast: excellent. Degradation processes: it is rated as permanent in oils but darkens and fades easily in watercolors. However, the pigment was never popular as an oil color and is much more widely available as a watercolor.	toxic. Harmful by inhalation and if swallowed. MSDS: Kremer

Literature:

Artists’ Pigments. A Handbook of Their History and Characteristics, Vol. 1, L. Feller, Ed., Cambridge University Press, London 1986, p. 37-46