The synthesis and crystal structures of two new hydrated sodium monofluorophosphates: NaHPO3F center dot 2.5 H2O (I) and Na2PO3F center dot 10 H2O (II)

The structures of two new sodium salts of monofluorophosphoric acid, NaHPO3 F . 2.5 H2O (I) and Na2PO3F . 10H(2)O (II), were determined with single-cry stal X-ray diffraction at 160 K. I is monoclinic with the space group C2/c, a = 19.112(4), b = 5.341(1), c = 12.727(3) Angstrom, beta = 110.18(3)degre es, V = 1219.4(4) Angstrom (3), and Z = 8 (R-1 = 0.0276 and wR(2) = 0.0647) . II crystallizes in the monoclinic space group, P2(1)/c, a = 11.380(3), b= 10.234(2), c = 13.051(4) Angstrom, P = 106.49(3)degrees, V = 1457.4(7)Angst rom (3), and Z = 4 (R-1 = 0.0266 and,wR(2) = 0.0581). The crystal structure of I contains hydrogen-bonded zigzag chains of HPO3F tetrahedra. The fluor ine atom does not participate in the hydrogen bonding system. In the struct ure of II, hydrogen bonds create a complex structure of water molecules con nected to each other and to the PO3F tetrahedron. The structure is isotypic to Na2SO4 . 10H(2)O with two disordered hydrogen atoms instead of four. Th e fluorine atom acts as an acceptor in two of the hydrogen bonds. (C) 2001 Academic Press.