Weil Matthias, Missen Owen P, Mills Stuart J
Institute for Chemical Technologies and Analytics, Division of Structural Chemistry, TU Wien, Getreidemarkt 9/E164-05-1, A-1060 Vienna, Austria.
School of Earth, Atmosphere and Environment, Monash University, Clayton 3800, Victoria, Australia.
Acta Crystallogr E Crystallogr Commun. 2023 Nov 30;79(Pt 12):1223-1227. doi: 10.1107/S205698902301023X. eCollection 2023 Dec 1.
The re-investigation of BiO(OH), dioxidodibismuth(III) hydroxide nitrate, on the basis of single-crystal X-ray diffraction data revealed an apparent structural phase transition of a crystal structure determined previously (space group 2 at 173 K) to a crystal structure with lower symmetry (space group 2 at 100 K). The 2 → 2 group-subgroup relationship between the two crystal structures is with index 2. In contrast to the crystal structure in 2 with orientational disorder of the nitrate anion, disorder does not occur in the 2 structure. Apart from the disorder of the nitrate anion, the general structural set-up in the two crystal structures is very similar: [BiO] layers extend parallel to (001) and alternate with layers of (OH) anions above and (NO) anions below the cationic layer. Whereas the (OH) anion shows strong bonds to the Bi cations, the (NO) anion weakly binds to the Bi cations of the cationic layer. A rather weak O-H⋯O hydrogen-bonding inter-action between the (OH) anion and the (NO) anion links adjacent sheets along [001].
基于单晶X射线衍射数据对BiO(OH)（二氧化二铋(III)氢氧化硝酸盐）的重新研究表明，先前确定的晶体结构（173 K时空间群为2）发生了明显的结构相变，转变为对称性较低的晶体结构（100 K时空间群为2）。这两种晶体结构之间的2 → 2群子群关系的指数为2。与2中硝酸根阴离子存在取向无序的晶体结构不同，2结构中不存在无序现象。除了硝酸根阴离子的无序外，这两种晶体结构的总体结构设置非常相似：[BiO]层平行于(001)延伸，并与阳离子层上方的(OH)阴离子层和下方的(NO)阴离子层交替排列。虽然(OH)阴离子与Bi阳离子形成强键，但(NO)阴离子与阳离子层的Bi阳离子弱结合。(OH)阴离子与(NO)阴离子之间相当弱的O-H⋯O氢键相互作用沿着[001]连接相邻的片层。
