Microcosmic salt

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Microcosmic salt[1]
IUPAC name
Ammonium sodium phosphate
Other names
Microcosmic salt, ammonium sodium phosphate, ammonium sodium hydrogen phosphate or phosphorsalz
3D model (Jmol)
ECHA InfoCard 100.128.899
EC Number 250-787-1
Molar mass 137.0077 g/mol
Appearance odorless crystals
Density 1.544 g/cm3
Melting point 80 °C (176 °F; 353 K)
5 parts cold, 1 part boiling water. Practically insoluble in ethanol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Microcosmic salt (see infobox for other names) is a salt found in urine with the formula Na(NH4)HPO4. It is left behind in the residues after extracting the urea from dried urine crystals with alcohol. In the mineral form, microcosmic salt is called stercorite.

The first extraction of pure phosphorus came from this salt, when Hennig Brandt attempted to extract gold from urine.

Microcosmic salt is used in the laboratory as an essential ingredient of the microcosmic salt bead test for identification of metallic radicals on the basis of the color they produce in oxidising or reducing flame, in hot or cold condition.

Microcosmic salts form a tetrahydrate.


  1. ^ The Merck Index (10th ed.). Merck and Co. Inc. 1983. p. 561. ISBN 0-911910-27-1.