Syntheses and crystal structures of two new sodium borates [Na2(H2O)3][B5O8(OH)2] and Na[enH2][B7O10(OH)4]

Two new sodium borates [Na-2(H2O)(3)][B5O8(OH)(2)] (1) and Na[enH(2)][B7O10(OH)(4)] (2) have been synthesized and their structures have been determined by single-crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic system space group C2/c with a = 11.118(2), b = 16.442(2), c = 13.572(2) angstrom, beta = 112.90(1)degrees, V = 2285.4(5) angstrom(3), and Z = 4. Compound 2 crystallizes in the triclinic space group P (1) over bar, with a = 7.4974(9), b = 8.349(2), c = 11.746(2), alpha = 93.98(1), beta = 97.25(1), gamma = 101.18(1)degrees, V = 712.2(2) angstrom(3), and Z = 2. Compound 1 possesses {Na2B5O8(OH)(2)center dot 3H(2)O}(n) chains which form through the connection of the fundamental building blocks (FBBs) [B5O8(OH)(2)](2-) by sharing Na+ ions, while compound 2 has infinite {Na[B7O10(OH)(4)]}(n) sheets which form via the connection of the FBBs [B7O10(OH)(4)](3-) by common Na+ ions.