CRYSTAL-STRUCTURES OF SODIUM-SULFATE DECAHYDRATE (GLAUBERS SALT) AND SODIUM TETRABORATE DECAHYDRATE (BORAX) - REDETERMINATION BY NEUTRON-DIFFRACTION
CRYSTAL-STRUCTURES OF SODIUM-SULFATE DECAHYDRATE (GLAUBERS SALT) AND SODIUM TETRABORATE DECAHYDRATE (BORAX) - REDETERMINATION BY NEUTRON-DIFFRACTION
复制标题
DOI：
10.1107/s0567740878011504
复制
发表时间：
1978-01-01
期刊：
影响因子：
--
通讯作者：
LISENSKY, GC
中科院分区：
文献类型：
--
作者：
LEVY, HA;LISENSKY, GC
经过全矩阵最小二乘改进的单晶中子衍射数据已经得到了两种化合物中所有原子（特别是氢原子）的精确位置。氢键与H原子位紊乱与相等占用，作为先前假定的是在硫酸盐的零点熵的来源，是定量验证。发现了一种涉及氢键重排的硫酸盐离子的热激发振动模式。这两种结构具有非常相似的钠离子链和配位水分子，并进行了详细的比较。不一致的度量是：对于硫酸盐，R (F2)= 0.082，为1750 F2> a (F2)；硼酸盐的R (F2)= 0.060，为1837f2 > (F2)。
Single-crystal neutron-diffraction data with full-matrix least-squares refinements have yielded precise locations for all atoms (for the H atoms in particular), in both compounds. Hydrogen bonding with H atom sites disordered with equal occupancy, as previously postulated to be the source of zero-point entropy in the sulfate, is quantitatively verified. A thermally excited librational mode of the sulfate ion involving a rearrange-ment of hydrogen bonding has been found. The two structures, which have closely similar chains of Na ions with coordinated water molecules, are compared in detail. Measures of disagreement are: for the sulfate, R (F2)= 0.082 for 1750 F2> a (F2); for the borate, R (F2)= 0.060 for 1837 F2> o (F2).