Diffuse X-ray scattering and reverse Monte Carlo simulation of the short-range order in ytterbium iodine phthalocyanine [YbPc(2)]I(2).
Diffuse X-ray scattering and reverse Monte Carlo simulation of the short-range order in ytterbium iodine phthalocyanine [YbPc(2)]I(2).
复制标题
镱碘酞菁 [YbPc(2)]I(2) 短程有序的漫 X 射线散射和反向蒙特卡罗模拟。
DOI：
10.1107/s0108768102009515
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
K. Łukaszewicz
中科院分区：
文献类型：
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作者：
J. Krawczyk;A. Pietraszko;K. Łukaszewicz
碘掺杂的酞菁镱，C(64)H(32)N(16)YbI(2), [YbPc(2)]I(2) (YPI)，是互生长型无序调制晶体结构的一个例子。用漫射x射线散射技术研究了YPI在常温下的短程阶态。Yb和I原子都是无序的。在平均结构的单晶胞中，Yb原子占据两个位置：1/2、1/2、1/4或1/2、1/2、3/4，占用率为0.5。然而，在（001）平面的相邻单元胞中，有一种强烈的趋势，即在移位z = 1/2的位置上交替分布镱。YPI的晶体结构由[YbPc(2)(2/3+)](n)和线性碘链[I(3)(-)](n)组成。调制是相称的，因为碘链[I(3)(-)](n)在[001]方向上的周期c(I)等于[YbPc(2)(2/3+)](n)堆栈周期c的一半。在晶体结构中，每一层[YbPc(2)(2/3+)](n)可以在两个位置上发生c/2的位移，每个碘链可以在三个位置上沿着[001]移动三分之一的周期c(I)。分布在三种环境中的碘链的短范围顺序导致了一个复杂的模式。相同设置的碘链倾向于形成垂直于<100>并沿[001]运行的带状。
Iodine-doped ytterbium phthalocyanine, C(64)H(32)N(16)YbI(2), [YbPc(2)]I(2) (YPI), presents an example of a disordered modulated crystal structure of the intergrowth type. The short-range order in YPI has been studied at ambient temperature by the diffuse X-ray scattering technique. Both Yb and I atoms are disordered. In a unit cell of the average structure, the Yb atoms occupy two positions, 1/2, 1/2, 1/4 or 1/2, 1/2, 3/4, with occupancy 0.5. In the neighbouring unit cells in the (001) plane there is, however, a strong tendency towards an alternating distribution of ytterbium in positions shifted by Delta z = 1/2. The crystal structure of YPI consists of one-dimensional columnar stacks of [YbPc(2)(2/3+)](n) and of linear iodine chains [I(3)(-)](n). The modulation is commensurate since the period c(I) of iodine chains [I(3)(-)](n) in the [001] direction is equal to one-half of the period c of the [YbPc(2)(2/3+)](n) stacks. In the crystal structure, each stack of [YbPc(2)(2/3+)](n) may occur in two settings shifted by c/2 and each iodine chain in three settings shifted along [001] by one-third of the period c(I). The short-range order of iodine chains distributed over three settings results in a complicated pattern. Iodine chains of the same setting tend to form ribbons perpendicular to <100> and running along [001].