Small corner configuration

ASTM D 3894-88 Standard Method for Evaluation of Fire Response of Rigid Cellular Plastics Using a Small Corner Configuration, 8 pp (Comm D-20)... 

ASTM D3894, Evaluation of fire response of rigid cellular plastics using a small corner configuration. 

The configuration of the twelve ligands about the small MnlV atom is that of an approximately regular icosahedron. The thirteen-cornered and sixteen-cornered coordination polyhedra about Mnl, Mnll, and Mnlll are appropriate to axial ratios slightly greater than unity. 

The discussion about the possible presence of a small contribution of d-n overlap forces at the surface of NiO is of interest because it may occur with Ni2+ interacting with adsorbates with r-acceptor characteristics, such as CO, NO (Section IV.I.2), and O2. IR spectra of O2 adsorbed at 77 K on progressively sintered NiO sampels (274) follow a trend similar to that observed for CO. In particular, on high-surface-area samples, O2 species formed at edge, step, and corner sites are predominant, whereas on progressively more sintered samples neutral species adsorbed in side-on configuration on Ni2+ of the (001) faces become the only species detectable by IR spectroscopy. 

Fig. 1.12. Selected atomic configurations from simulations of collisions of an initially ordered NaCl nanocrystal (Na, small spheres Cl, large spheres) with adsorbed Ar or Ne fluids. Disordered (glassy) (NaCl)32 cluster at (a) t = 2ps and (b) t = 8ps in collision with an Ar film. Ordered cubic clusters from the limiting cases of initial orientation (c) face toward target surface and (d) corner toward surface, soft-landed on an Ne film (t = 5ps). The structural defect in (c) was caused by the initial impact with the liquid surface. Glassy nanocluster configurations, at (e) t = 2ps and (f) t = 22 ps, formed in a higher energy colhsion (center-of-mass velocity of 4 km s ) with a thick Ar film (only a portion of the system surrounding the cluster is shown). In aU cases, the structures of the clusters at longer times remain virtually the same as the ones shown [97]...

In the solid state, Se02 has a polymeric structure of corner-linked flattened SeOs pyramids, each carrying a pendant terminal 0 atom. Mass spectrometric studies of the vapor over solid Se02 at 400 K indicate small amounts (1%) of dimeric Se02 in the gaseous phase.A normal-coordinate calculation for the four possible symmetries of (8002)2 prove the centrosymmetric Cm chair configuration (11) for the dimeric molecule. 

Our own cluster calculations were performed at different levels of approximation. We started with a free Za O cluster with the wurtzite-hke structure of bulk ZnO [128]. This cluster is shown in Fig. 4a. It has the advantage that its dipole moment is still so small (in contrast to the Zn O cluster shown in Fig. lb) that it will not affect the results too much. Furthermore, it contains threefold (3C) and twofold (2C) coordinated Zn and O atoms and can therefore serve as a model for threefold coordinated Zn atoms on the terraces of the (0001) plane or at edges on the (10-10) plane as well as for twofold coordinated Zn atoms at various types of corners. The results for all those configurations of CO on Zn404 which exhibit an attractive interaction are collected in Table 6. They show without any doubt that CO will only bind to Zn atoms, with... 

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