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β-TiCl3 is usually prepared according to the reaction: by mixing heptane solutions of the reactants. The product thus obtained, however, is not suitable for determinations of X-ray structure, because of the poor quality of the powder patterns. Natta et al.1obtained better X-ray photographs from samples prepared by thermal decomposition of CH3TiCl3 (ref. 2). From these photographs they arrived at a crystal structure which is very similar to the structures of the needle-shaped modification of TiBr3, TiI3 and the zirconium trihalogenides3.

The effect of comonomer content and the distribution of side chain branching on thermal, viscoelastic, rheological, and mechanical properties was investigated using the ethylene 1-octene copolymer (EOC) blends, which consist of one component by the Ziegler-Natta and another by the metallcoens catalysis. Two model blend systems were selected; one was composed of FA+FM, which were made using the Ziepler-Natta and metallocene catalysis, respectively, and which has a similar melf index (MI), density, and comonomer content. The other blend was composed of SF+FM, which were also made using the Ziegler-Natta and metallocene catalysts, respectively, however, despite similar (MI) and density they had different comonomer contents. The big difference between the Zieler- Natta and metallocene EOC's is the comonomer distribution and the length of the side chain branching. Regardicess of the blending methods (solution and melt blending), the blends exhibited two distinct melting and drystallzation peaks, implying that the consituents excluded one another during crystallization. A single ？ relaxation shifted to a lower temperature relative to the content of metallocene EOC, thereby indicating miscitility in the amorphous region. In addition, the mechanical properties seemed to have no dependency on the comonomer content. Hence the properties of EOC blends consisting of components with a similar MI and density influenced by both the comonomer contents and the distribution of the side chain branching.

It is more than 30 years since the foundation of organo-transition metal chemistry and its useful applications. The names of Nobel Laureates E. O. Fischer and G. Wilkinson, K .Ziegler and G. Natta are associated with the earliest years of the development of this field. Indeed, the early chemistry of hydrocarbon derivatives of transition metals was largely developed by inorganic chemists whose primary interest focused on the transition metal chemistry rather than on transformations of organic compounds. Apart from a few, academic organic chemists were rather slow to appreciate the potential of organo-transition metal compounds as synthetic intermediates. What were the reasons for this delay? It was perhaps because in the early days of the development of organo-transition metal chemistry it was difficult to perceive pattern and order in the abundant complexity of new structural types and reactivities. Indeed, in the early days the fragmentary knowledge and understanding mitigated against much pretence of deeply argued strategies for research. Also, new techniques such as the need to work under an inert atmosphere with a vacuum/nitrogen line were unfamiliar to organic chemists

SEVERAL attempts to obtain X-ray diffraction patterns of crystalline white phosphorus have been made1. It is claimed by some that the ready reversion of the white to the red form under irradiation with X-rays prevents any pattern being obtained, while others suggest that the high degree of thermal motion in the crystal lattice will render it impossible to obtain anything but a few very diffuse rings. Natta and Passerini2, however, state that they obtained a well-defined powder photograph of white phosphorus with 22 lines, using iron Kα radiation at − 35° C. They claim that the substance is cubic with [a] = 7.17 A., containing four molecules of P4 per unit cell, but give no other data.