CRYSTALLOGRAPHIC DATA ABOUT HYDRATED AND ANHYDROUS LITHIUM MONOBORATES

The anhydrous and hydrated lithium monoborates have been studied. The most hydrated phase is LiBO2 . 8H(2)O; its structural formula in the P 3 space group is Li(H2O)(4)B(OH)(4) .2H2O. Refinement of the cell para meters yielded the following results: a=6.5483(5) Angstrom, c=6.1692(7 ) Angstrom with F(30)=64(0.015, 32), Z=1, and D-x=1.402 g/cm(3). This phase gives LiB(OH)(4) by spontaneous dehydration. An X-ray powder dif fraction study of LiB(OH)4 as a function of temperature indicated thre e poorly crystallized hydrates. Two of these hydrates have the formula LiBO2 . 0.3H(2)O; the other, LiBO2 . xH(2)O, has an undetermined wate r content. Crystal data for alpha-LiBO2 have been obtained: a=5.8473(1 0) Angstrom, b=4.3513(6) Angstrom, c=6.4557(10) Angstrom, beta=115.08( 1)degrees, F(27)=58.5(0.001, 41); space group P2(1)/c, Z=4, and D-x=2. 18 g/cm(3). beta-LiBO2 does not exist but corresponds to the alpha-LiB O2 form observed at 600 degrees C. Numerous other LiBO, forms reported recently have not been found. (C) 1997 International Centre Sor Diffr action Data.