M. Mathew, W. Wong-Ng
1995
Citations
0
Influential Citations
19
Citations
Journal
IEEE Journal of Solid-state Circuits
Abstract
Abstract The crystal structure of a new monoclinic form of potassium dihydrogen phosphate, KH2PO4, has been determined by single crystal X-ray diffraction. Crystals are monoclinic, space group P2/c with a = 7.4399(7), b = 7.2634(9), c = 9.3629(13) A, β = 127.696(8)°, V = 400.35(9) A3, dm = 2.25, dc = 2.257 Mg m-3 for Z = 4, μ = 17.9 cm-1, F(000) = 272, T = 293 K. The structure was refined to R = 0.022 and Rw = 0.038 for 740 reflections with I ≥ 3σ(I). The crystal structure consists of a compact assembly of potassium and phosphate ions, arranged in columns along the b-axis, bound by K···O ionic bonds and O-H···O hydrogen bonds in a three-dimensional network as in all other forms of KH2PO4 and KD2PO4. The two crystallographically nonequivalent phosphate groups appear to exist as an orthophosphacidium ion, [H4PO4]+ and a PO4-3 ion rather than as the expected H2PO4 ions. This study provides the first example of crystal structure determination of the [P(OH)4]+ ion.