A new crystal modification of diammonium hydrogen phosphate, (NH₄)₂(HPO₄)

Abstract

The addition of hexa­fluorido­phosphate salts (ammonium, silver, thallium or potassium) is usually used to precipitate complex cations from aqueous solutions. It has long been known that PF6 − is sensitive towards hydrolysis under acidic conditions [Gebala & Jones (1969 ▶). J. Inorg. Nucl. Chem. 31, 771–776; Plakhotnyk et al. (2005 ▶). J. Fluorine Chem. 126, 27–31]. During the course of our investigation into coinage metal complexes of diphosphine ligands, we used ammonium hexa­fluorido­phosphate in order to crystallize [Ag(diphos­phine)2]PF6 complexes. From these solutions we always obtained needle-like crystals which turned out to be the title compound, 2NH4 +·HPO4 2−. It was received as the hydrolysis product of NH4PF6. The crystals are a new modification of diammonium hydrogen phosphate. In contrast to the previously published polymorph [Khan et al. (1972 ▶). Acta Cryst. B28, 2065–2069], Z′ of the title compound is 2. In the new modification of the title compound, there are eight mol­ecules of (NH4)2(HPO4) in the unit cell. The structure consists of PO3OH and NH4 tetra­hedra, held together by O—H⋯O and N—H⋯O hydrogen bonds.

Design, Synthesis, Crystal Structure, and Fungicidal Activity of L-Carvone Derivatives Containing an Oxime Ester Moiety

“…The data was processed using CrysAlisPro software. [43] The structures were computed via direct methods employing Olex2 software. [44] The non-hydrogen atoms located on the experimental structure were refined anisotropically with SHELXL-2018 employing full-matrix least squares procedure based on F 2 .…”

The isotypic hydrogen phosphate and arsenate dihydratesM2HXO4·2H2O (M= Rb, Cs;X= P, As)

“…The crystal structures of (NH 4 ) 2 HPO 4 (Khan et al, 1972) and (NH 4 ) 2 HAsPO 4 (Weil, 2012) have been elucidated. They are isotypic and a second polymorph has been reported for (NH 4 ) 2 HPO 4 (Kunz et al, 2010). Recently, we have determined the crystal structures of the 2.5-and 6-hydrates of KH 2 AsO 4 (Stö ger et al, 2012).…”

Redetermination of (NH4)2HAsO4

“…ammonium hexafluoridophosphate (Kunz et al, 2010). It would be interesting to know whether an arsenate polymorph isotypic with the phosphate analogue or another polymorph (NH 4 ) 2 HAsO 4 exist as well.…”

“…The arsenate compound is isotypic with the phosphate analogue (NH 4 ) 2 HPO 4 (Khan et al, 1972), for which another modification with Z 0 = 2 has also recently been described (Kunz et al, 2010).…”