Synthesis and crystal structure of K-2(HSO4)(H2PO4), K-4(HSO4)(3)(H2PO(4)), and Na(HSO4)(H3PO4)

Mixed hydrogen sulfate phosphates K-2(HSO4)(H2PO4), K-4(HSO4)(3)(H2PO4) and Na(HSO4)(H3PO4) were synthesized and characterized by X-ray single crystal analysis. In case of K-2(HSO4)(H2PO4) neutron powder diffraction was used additionally. For this compound an unknown supercell was found. According t o X-ray crystal structure analysis, the compounds have the following crysta l data: K-2(HSO4)(H2PO4) (T = 29 K), monoclinic, space group P2(1)/c, a = 1 2.150(4) Angstrom, b = 7.371(2) Angstrom, c = 9.436(3) Angstrom, beta = 92. 29(3)degrees, V = 774.9(4) Angstrom(3), Z = 4, R-1 = 0.039; K-4(HSO4)(3)(H2 PO4) (T = 298 K), triclinic, space group P (1) over bar, a = 7.217(8) Angst rom, b = 7.521(9) Angstrom, c = 7.574(8) Angstrom, alpha = 71.52(1)degrees, beta = 88.28(1)degrees, gamma = 86.20(1)degrees, V = 389.1(8) Angstrom(3), Z = 1, R-1 = 0.031; Na(HSO4)(H3PO4) (T = 298 K), monoclinic, space group P 2(1), a = 5.449(1) Angstrom, b = 6.832(1) Angstrom, c = 8.718(2) Angstrom, beta = 95.88(3)degrees, V = 322.8(1) Angstrom(3), Z = 2, R-1 = 0,032. The m etal atoms are coordinated by 8 or 9 oxygen atoms. The structure of K-2(HSO 4)(H2PO4) is characterized by hydrogen bonded chains of mixed HnS/PO4- tetr ahedra. In the structure of K-4(HSO4)(3)(H2PO4), there are dimers of HnS/PO 4- tetrahedra, which are further connected to chains. Additional HSO4- tetr ahedra are linked to these chains. In the structure of Na(HSO4)(H3PO4) the HSO4- tetrahedra and H3PO4 molecules form layers by hydrogen bonds.