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SnO₂ (Tin Oxide, Stannic Oxide)

Family	Other
Weight	150.710

COLE - Co-efficient of Linear Expansion	0.020
MLPT - Melting Point (MP)	1625C (From The Oxide Handbook)

Notes

More correctly called Tin Dioxide

-The fully oxidized state of tin metal. It is a very white powder of low density. Although tin metal melts at a very low temperature, the oxide form is quite refractory.

-Tin oxide has been used primarily as an opacifier in amounts of 5-15% in all types of glazes for many centuries. The amount required varies according to the glaze composition and temperature. The mechanism of the opacity depends on the white tin particles being in suspension in the molten glass. At higher temperatures, these particles will start to dissolve and opacity will begin to be compromised.

-Like zirconium oxide, larger amounts of tin in lower temperature glazes have a refractory effect, stiffening the melt and increasing the incidence of pinholing and crawling.

-Tin white is considered a softer white than that produced by the very popular and much cheaper zirconium opacifiers.

-One peril with tin is that it reacts very strongly with minute amounts of chrome to produce pink colors. If volatile chromium is flashing in the kiln atmosphere from other glazes, the white color will be lost.

-Other opacifiers include zirconium oxide (gives a harsher glassy white), calcium phosphate (problems with off-coloring to greys), cerium oxide (restricted to low temperatures), antimony (dissolves in some glazes and gives yellows with lead), and titanium dioxide (discolors if any iron oxide is present).

Mechanisms

Glaze Color - Pink
Chrome and tin are the most well known way to produce pink. For example, 7.5% tin and 0.5 chrome oxide will produce pink. Many Cr-Sn stains are available to make many shades on pink. However this mechanism requires that the glaze chemistry be right (e.g. no zinc, boron not excessive) for slow firings (in industry firing is typically so fast that the stain does not get an opportunity to react with the zinc).
Glaze Opacifier - White
Tin is an effective opacifier to transform transparent glazes to white. The quality of color tends to be a 'soft-bluish white' compared to harsher effects with other oxides.

Out Bound Links

(Materials - Closest material equivalent) Tin Oxide - SnO2
Stannic Oxide, Tin(IV) Oxide, Tin Dioxide, SnO2
(Articles)
Formulating a Clear Glaze Compatible with Chrome-Tin Stains
In ceramics color is often a matter of chemistry, that is, the host glaze must be compatible and hav...
(URLs) Tin Oxide at Wikipedia
http://en.wikipedia.org/wiki/Tin_dioxide

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SnO2 (Tin Oxide, Stannic Oxide)

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SnO₂ (Tin Oxide, Stannic Oxide)