A new biogenic, struvite-related phosphate, the ammonium-analog of hazenite,(NH4) NaMg2 (PO4) 2• 14H2O

A new biogenic, struvite-related phosphate, the ammonium analog of hazenite (AAH), ideally (NH4)NaMg2(PO4)2·14H2O, has been found in cultures containing the bacterial strain Virgibacillus sp.NOT1 (GenBank Accession Number: [JX417495][1].1) isolated from an XVII Century document made of parchment. The chemical composition of AAH, determined from the combination of electron microprobe and X-ray structural analyses, is [(NH4)0.78K0.22]NaMg2(PO4)2·14H2O. Single-crystal X-ray diffraction shows that AAH is orthorhombic with space group Pmnb and unit-cell parameters a = 6.9661(6), b = 25.236(3), c = 11.292(1) A, and V = 1985.0(3) A3. Compared with hazenite, the substitution of NH4+ for K+ results in a noticeable increase of the average A -O ( A = NH4++K+) bond length and the unit-cell volume for AAH, as also observed for struvite vs. struvite-K. Both infrared and Raman spectra of AAH resemble those of hazenite, as well as struvite. Our study reveals that AAH forms only in cultures with Na-bearing solutions and pH below 10.0. No AAH or hazenite was found in experiments with the K-bearing solutions, suggesting the necessity of a Na-bearing solution for AAH formation. [1]: /lookup/external-ref?link_type=GEN&access_num=JX417495&atom=%2Fgsammin%2F99%2F8-9%2F1761.atom