Crystal structure and thermal behavior of NaCs[B4O5(OH)4]·4H2O

The crystal of a new tetraborate, NaCs[B4O5(OH)4]·4H2O was synthesized in CsB5O8·4H2O and NaOH solution at 30 8C for 30 days and its crystal structure was determined from single crystal X-ray diffraction data. The compound is monoclinic, space group P21=c; the unit cell parameters are a ¼ 8:240ð1Þ; b ¼ 11:493ð1Þ and c ¼ 12:900ð2Þ A ° , b ¼ 92:11ð1Þ8; Z ¼ 4; V ¼ 1220:8ð3Þ A ° 3; Dc ¼ 2:281 g cm21, m ¼ 3:13 mm21, Fð000Þ ¼ 808: The crystal structure was determined from 2078 reflection until R1 ¼ 0:0228 and wR2 ¼ 0:0548: The structure contains of layers of isolated [B4O5(OH)4]22 polyanions separated by free water molecules and Csþ and Naþ cations. A structural comparison between NaCs[B4O5(OH)4]·4H2O and Cs2[B4O5(OH)4]·3H2O was done. The thermal analytical curve of this compound was recorded and its decomposition mechanism was discussed. q 2003 Elsevier B.V. All rights reserved