Crystalline Phases
Transformations of the crystal states due to changing conditions (temperature, pressure) affect the physical properties of ammonium nitrate. The following crystalline states have been identified:
| System | Temperature (°C) | State | Volume Change (%) |
|---|---|---|---|
| - | > 169.6 | liquid | - |
| I | 169.6 to 125.2 | cubic | +2.1 |
| II | 125.2 to 84.2 | tetragonal | −1.3 |
| III | 84.2 to 32.3 | α-rhombic | +3.6 |
| IV | 32.3 to −16.8 | β-rhombic | −2.9 |
| V | −16.8 | tetragonal | - |
The type V crystal is a quasi-cubic form which is related to caesium chloride, the nitrogens of the nitrates and the ammoniums are at the sites in a cubic array where Cs and Cl would be in the CsCl lattice. See C.S. Choi and H.J. Prask, Acta Crystallographica B, 1983, 39, 414-420.
Read more about this topic: Ammonium Nitrate
Famous quotes containing the words crystalline and/or phases:
“The air was so elastic and crystalline that it had the same effect on the landscape that a glass has on a picture, to give it an ideal remoteness and perfection.”
—Henry David Thoreau (1817–1862)
“That man is to be pitied who cannot enjoy social intercourse without eating and drinking. The lowest orders, it is true, cannot imagine a cheerful assembly without the attractions of the table, and this reflection alone should induce all who aim at intellectual culture to endeavor to avoid placing the choicest phases of social life on such a basis.”
—Mrs. H. O. Ward (1824–1899)