Neutron diffraction study of MgNH₄PO₄.6H₂O (struvite) and survey of water molecules donating short hydrogen bonds

The struvite‐type compounds M [Mg(H2O)6](X O4), where M = Rb, Tl and X = P, As

“…The measured intensities were corrected for Lorentz and polarization effects, and numerical absorption corrections were applied using HABITUS [14]. All crystal structures were refined with SHELXL-97 [15], using the starting coordinates (except of the H positions of the ammonium cations) from structural data of struvite [6]. In the final refinement cycles, the temperature factors of all non-H atoms were refined anisotropically.…”

“…On the other hand, the latter negative effect is reversed when struvite is used to recover phosphorus and ammonium from wastestreams by systematic precipitation and is subsequently recycled as a useful Mg-N-P-containing fertilizer [3]. Such a positive impact can also be used for the related arsenate system to permanentely remove arsenic from drinking and waste waters by systematic precipitation of arsenostruvite, NH 4 6 ](AsO 4 ), many efforts have been undertaken for a detailed characterisation of these compounds including full structural studies [4][5][6]. Although other struvite analogues are known for a long time, where ammonium is replaced by an alkali or the pseudo-alkali metal cation Tl + [7], and/or magnesium is replaced by a divalent first-row transition metal, merley the structures of [12], and [13] were completely characterized.…”

X-ray Absorption Fine Structure Study of the Effect of Protonation on Disorder and Multiple Scattering in Phosphate Solutions and Solids

“…21 Theoretical backscattering phases and amplitudes and local density of states were calculated with the FEFF 8 22 code using input files generated from crystal structure data of the studied solids. [23][24][25][26][27][28] The amplitude reduction factor, S 0 2 was determined from firstshell fits to solid reference samples. Obtained values were averaged and S 0 2 fixed at 0.8 for subsequent fits.…”

Thermochemical Properties and Decomposition Kinetics of Ammonium Magnesium Phosphate Monohydrate

“…These compounds have been used widely as slow release fertilizers, 1,2 feedstuff additives and fire retardants. Their crystal structure, [3][4][5][6] phase change 7 and spectroscopic properties 8,9 have been reported in previous papers. The thermal decomposition of ammonium magnesium phosphate hexahydrate has been investigated by Paul.…”