The Hexamethylenetetramine Adduct [Mg<sub>3</sub>(H<sub>2</sub>O)<sub>14</sub>][Fe(CN)<sub>6</sub>]<sub>2</sub>(C<sub>6</sub>H<sub>12</sub>N<sub>4</sub>)<sub>4</sub>(H<sub>2</sub>O)<sub>4.18</sub>, Its Potential as Testing Agent for Mg<sup>2+</sup> I
Isotypic compounds [Mg<sub>3</sub>(H<sub>2</sub>O)<sub>14</sub>][M(CN)<sub>6</sub>]<sub>2</sub>·4HMT·<i>x</i>H<sub>2</sub>O (HMT = hexamethylenetetramine or urotropine) with M = Fe, Cr, and Co are crystallized from aqueous solutions. The iron compound (M = Fe) is most remarkable because it crystallizes with distinctive thin, deep-yellow crystal plates. The crystal structure of [Mg<sub>3</sub>(H<sub>2</sub>O)<sub>14</sub>][Fe(CN)<sub>6</sub>]<sub>2</sub>(C<sub>6</sub>H<sub>12</sub>N<sub>4</sub>)<sub>4</sub>(H<sub>2</sub>O)<sub>4.18</sub> is solved and refined by X-Ray single-crystal diffraction, revealing the tetragonal space group <i>P</i>4<i>c</i>2, with <i>a</i> = 14.8156(5) Å, and <i>c</i> = 32.890(3) Å (Z = 4). The structure contains finite cyanido-bridged linear sequences of the type [(H<sub>2</sub>O)<sub>5</sub>Mg–(Fe(CN)<sub>6</sub>)–(Mg(H<sub>2</sub>O)<sub>4</sub>)–(Fe(CN)<sub>6</sub>)–Mg(H<sub>2</sub>O)<sub>5</sub>] being arranged parallel to the tetragonal axis with HMT and crystal water molecules in-between these patterns. The straightforward synthesis and the characteristic appearance of crystals of this compound can make this reaction a useful test to proof the presence of Mg<sup>2+</sup> ions in aqueous solution. Thermoanalytical studies, designed to investigate the loss of water molecules and the decomposition pathway, reveal this compound as a useful precursor for the preparation of ferromagnetic cementite (Fe<sub>3</sub>C).
Publication Details
- Journal
- Archive ouverte UNIGE (University of Geneva)
- Published
- 2025-01-01
- Primary Topic
- Diverse Scientific and Economic Studies
- Type
- article
- Field-Weighted Citation Impact
- 0.00