Difference between revisions of "Preparing ammonium hexafluorozirconate"
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| − | Ammonium hexafluorozirconate - (NH<sub>4</sub>)<sub>2</sub>ZrF<sub>6</sub> - is prepared by dissolving freshly precipitated Zr(OH)<sub>4</sub>[http://www.sciencemadness.org/smwiki/index.php/Zirconia_preparation] in concentrated ammonium bifluoride - NH<sub>4</sub>HF<sub>2</sub> in a polypropylene beaker. A 10 % excess of ammonium bifluoride is used: | + | Ammonium hexafluorozirconate - (NH<sub>4</sub>)<sub>2</sub>ZrF<sub>6</sub> - is prepared by dissolving freshly precipitated Zr(OH)<sub>4</sub>[http://www.sciencemadness.org/smwiki/index.php/Zirconia_preparation] in concentrated ammonium bifluoride - NH<sub>4</sub>HF<sub>2</sub> - solution in a polypropylene beaker. A 10 % excess of ammonium bifluoride is used: |
Zr(OH)<sub>4</sub>(s) + 3 NH<sub>4</sub>HF<sub>2</sub>(aq) === > (NH<sub>4</sub>)<sub>2</sub>ZrF<sub>6</sub>(aq) + NH<sub>3</sub>(aq) + 4 H<sub>2</sub>O(l) | Zr(OH)<sub>4</sub>(s) + 3 NH<sub>4</sub>HF<sub>2</sub>(aq) === > (NH<sub>4</sub>)<sub>2</sub>ZrF<sub>6</sub>(aq) + NH<sub>3</sub>(aq) + 4 H<sub>2</sub>O(l) | ||
Revision as of 17:49, 31 January 2016
Ammonium hexafluorozirconate - (NH4)2ZrF6 - is prepared by dissolving freshly precipitated Zr(OH)4[1] in concentrated ammonium bifluoride - NH4HF2 - solution in a polypropylene beaker. A 10 % excess of ammonium bifluoride is used:
Zr(OH)4(s) + 3 NH4HF2(aq) === > (NH4)2ZrF6(aq) + NH3(aq) + 4 H2O(l)
The reaction is accompanied with heat generation. Gently simmer the solution on steam bath to obtain full dissolution. If the solution is still turbid, hot-filter to clarity.
On cooling and chilling overnight, well-formed crystals of ammonium hexafluorozirconate are obtained.
Pyrolysis of ammonium hexafluorozirconate yields zirconium tetrafluoride:
(NH4)2ZrF6(s) === > ZrF4(s) + 2 NH4F(g)
