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) 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) Å, and V = 1985.0(3) Å3. 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.
All Science Journal Classification (ASJC) codes
- Geochemistry and Petrology
Yang, H., Martinelli, L., Tasso, F., Sprocati, A. R., Pinzari, F., Liu, Z., Downs, R. T., & Sun, H. J. (2014). A new biogenic, struvite-related phosphate, the ammonium-analog of hazenite, (NH. American Mineralogist, 99(8-9), 1761 - 1766. https://doi.org/10.2138/am.2014.4768