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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Shared and closed-shell O-O interactions in silicates
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Shared and closed-shell O-O interactions in silicates

机译：硅酸盐中的共享和闭壳O-O相互作用

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摘要

Bond paths of maximum electron density spanning O-O edges shared between equivalent or quasiequivalent MOn (n > 4) coordination polyhedra are not uncommon electron density features displayed by silicates. On the basis of the positive values for the local electronic energy density, H(r(c)), at the bond critical points, r(c), they qualify as weak "closed-shell" interactions. As observed for M-O bonded interactions (M = first and second row metal atoms), the electron density, rho(r(c)), and the Laplacian of the electron density increase in a regular way as the separation between the O atoms, R(O-O), decreases. A simple model, based on R(O-O) and the distances of the Si atoms from the midpoint between adjacent pairs of O atoms, partitions the O-O bond paths in the high-pressure silica polymorph coesite into two largely disjoint domains, one with and one without bond paths. The occurrence of O-O bond paths shared in common between equivalent coordination polyhedra suggests that they may be grounded in some cases on factors other than bonded interactions, particularly since they are often displayed by inert procrystal representations of the electron density. In these cases, it can be argued that the accumulation of the electron density along the paths has its origin, at least in part, in the superposition of the peripheral electron density distributions of the metal M atoms occupying the edge-sharing polyhedra. On the other hand, the accumulation of electron density along the paths may stabilize a structure by shielding the adjacent M atoms in the edge-sharing polyhedra. For closed-shell Li-O, Na-O, and Mg-O interactions, H(r(c)) is positive and increases as the value of rho(r(c)) increases, unlike the "shared" Be-O, B-O, C-O, Al-O, Si-O, P-O, and S-O interactions, where H(r(c)) is negative and decreases as rho(r(c)) increases. The H(r(c)) values for the weak closed-shell O-O interactions also increase as rho(r(c)) increases, as observed for the closed-shell M-O interactions. On the basis of the bond critical point properties and the negative H(r(c)) value, the O-O interaction comprising the O-2 molecule in silica III qualifies as a shared interaction.
机译：在等效或准等价的MOn（n> 4）配位多面体之间共享的跨越O-O边缘的最大电子密度的键路径并非常见的硅酸盐电子密度特征。根据局部电子能量密度H（r（c））的正值，在键的临界点r（c）上，它们被视为弱的“闭壳”相互作用。如观察到的MO键相互作用（M =第一和第二行金属原子），随着O原子之间的间距R，电子密度rho（r（c））和电子密度的拉普拉斯规律增加。 （OO）减小。一个简单的模型基于R（OO）和相邻的O原子对之间的Si原子到中点的距离，将高压二氧化硅多晶型堇青石中的OO键路径分为两个基本不相交的区域，一个具有一个，另一个具有一个没有键路径。等效配位多面体之间共有的O-O键路径的出现表明，在某些情况下，它们可能以键合相互作用以外的其他因素为基础，特别是因为它们通常由电子密度的惰性原晶表示来显示。在这些情况下，可以论证的是，沿路径的电子密度的累积至少部分地源于占据边缘共享多面体的金属M原子的外围电子密度分布的叠加。另一方面，沿着路径的电子密度的积累可以通过遮蔽边缘共享多面体中的相邻M原子来稳定结构。对于闭壳的Li-O，Na-O和Mg-O相互作用，H（r（c））为正值，并且随着rho（r（c））的值增加而增加，这与“共享” Be-O不同，BO，CO，Al-O，Si-O，PO和SO相互作用，其中H（r（c））为负，并随着rho（r（c））的增加而降低。正如在闭壳M-O相互作用中观察到的那样，弱的闭壳O-O相互作用的H（r（c））值也随着rho（r（c））的增加而增加。基于键的临界点性质和负H（r（c））值，二氧化硅III中包含O-2分子的O-O相互作用被视为共享相互作用。

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