Chemical properties of Ammonium perrhenate (APR)
- Atomic mass:
- 268.24 g.mol -1
- Formula:
- NH4ReO4
- CAS Number:
- 13598-65-7
Ammonium perrhenate (APR) is the ammonium salt of perrhenic acid, NH4ReO4. It is the most common form in which rhenium is traded. It is a white, water-soluble salt. It was first described soon after the discovery of rhenium.
The crystal structure of APR is that of scheelite, in which the atomic cation is replaced by the ammonium molecular cation. It undergoes a molecular orientational ordering transition on cooling without change of space group, but with a highly anisotropic change in the shape of the unit cell, resulting in the unusual property of having a positive temperature and pressure Re NQR coefficient.
NH4ReO4 can be regarded as the prototype structure of a family of ammonium scheelites, which include the pertechnetate (NH4TcO4), periodate (NH4IO4), tetrachlorothallate (NH4TlCl4) and tetrachloroindate (NH4InCl4).
The crystal structure of APR is that of scheelite, in which the atomic cation is replaced by the ammonium molecular cation. It undergoes a molecular orientational ordering transition on cooling without change of space group, but with a highly anisotropic change in the shape of the unit cell, resulting in the unusual property of having a positive temperature and pressure Re NQR coefficient.
NH4ReO4 can be regarded as the prototype structure of a family of ammonium scheelites, which include the pertechnetate (NH4TcO4), periodate (NH4IO4), tetrachlorothallate (NH4TlCl4) and tetrachloroindate (NH4InCl4).
