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Sodium Uranyl Acetate Crystals

Sodium Uranyl Acetate in the Presence of Sucrose

These tetrahedral skeletal crystals form if sodium is present in a sucrose solution added to a uranyl acetate solution. Sucrose interferes with the crystal growth on the face of the crystals. The result is this skeletal form

Transmitted Oblique Illumination


These are characteristic crystals of Na(C2H3O2)-A standard test for sodium is to test the dry salt with a solution of uranyl acetate (UO2(C2H3O2)-2H2O) in water made acid with a little acetic acid. In this case the presence of sodium ions in a sucrose solution was at issue. In the presence of sucrose the crystal habit is slightly modified.

Significance in the Environment:

Characteristic Features:

Sodium Uranyl acetate has a relatively high refractive index and so may appear black due to total internal reflection if illuminated with transmitted, centered Kholer illumination. Transmitted oblique illumination will allow some light to come through on one or two of the crystal faces.

Associated Particles:

A number of other crystalline or non-crystalline phases may be present. A summary of the elements that may cause these other precipitates is given on page 57 and 58 of Chamot and Mason.


Chamot, Emile Monnin and Clyde Walter Mason, HANDBOOK OF CHEMICAL MICROSCOPY, Volume II, pp. 51-58, 1940.