Cobalt binary compounds

Only one example is known of a binary homoleptic (see Homoleptic Compound) cobalt alkyl compound, Co(nb)4... 

The binary cobalt and yttrium silicides aie in good agreement with more recent data and are discussed in combination with the systems Ce-Co-Si and Y-Ni-Si, respectively. Mutual solid solubilities of binary compounds have been found to be... 

It was established by [1965Buz] that the ratio Co/S in the cobalt sulfide of the Co-Fe-S system equals 0.97, which corresponds to the Coi (S binary compound. 

Ans. The three compounds belong to different nomenclature classes. Aluminum in its compounds always forms 3+ ions, and thus there is no need to state 3+ in the name. Cobalt forms 2+ and 33-ions, and we need to designate which of these exists in this compound. PCI, is a binary nonmctal-nonmetal compound, using a prefix to denote the number of chlorine atoms. 

Because Ni(CO)4 is volatile (b.p. 43 °C) and cobalt will not react under these conditions, this process afforded a method for separating Ni from Co by the process now known as the Mond process. Although there are many complexes known that contain both carbonyl and other ligands (mixed carbonyl complexes), the number containing only a metal and carbonyl ligands is small. They are known as binary metal carbonyls, and they are listed in Table 21.1. The structures of most of these compounds are shown later in Figures 21.1 through 21.3. 

Hence, none of the two above-mentioned criteria can be used as a reliable basis for predicting the sequence of occurrence of chemical compound layers in multiphase binary systems. The experimental data on the formation of nickel and cobalt silicides provides additional evidence for the validity of this conclusion. 

Apart from the work on binary metal carbonyls and metal carbonyl hydrides, Flieber and his school also greatly extended the field of carbonyl(ni-trosyl) metal complexes. The first compound of the general composition M(CO)x(NO)- was obtained by Robert L. Mond and Albert Wallis as early as in 1922 [67]. While studying the reactivity of Co2(CO)8 toward various substrates, they observed that slowly at room temperature, but almost instantaneously at 40°C, nitric oxide gas reacts with cobalt tetracarbonyl to form a cherry-red liquid, with the evolution of carbon monoxide . This liquid was... 

In addition to the binary catalysts from transition metal compounds and metal alkyls there 2ire an increasing number which are clearly of the same general type but which have very different structures. Several of these are crystalline in character, and have been subjected to an activation process which gives rise to lattice defects and catalytic activity. Thus, nickel and cobalt chlorides, which untreated are not catalysts, lose chlorine on irradiation and become active for the polymerization of butadiene to high cis 1,4-polymer [59]. Titanium dichloride, likewise not a catalyst, is transformed into an active catalyst (the activity of which is proportional to the Ti content) for the polymerization of ethylene [60]. In these the active sites evidently react with monomer to form organo-transition metal compounds which coordinate further monomer and initiate polymerization. 

Binary or ternary catalyst systems from nickel compounds with Group I—III metal—alkyls have many features in common with those from cobalt and it may be inferred that a similar type of catalytic entity is involved. The composition for optimum activity may be different, however, and in the soluble catalyst Ni(naphthenate)2/BF3. EtjO/AlEtj (Ni/B/Al = 1/7.3/6.5) [68] the ratio of transition metal to aluminium is much higher than in cobalt systems. Rates were proportional to [M] and [Ni], molecular weight was limited by transfer with monomer and catalyst efficiency was relatively low (Table 5, p. 178). With the system AlEtj/ Ni(Oct)2/BF3—Et2 0 (17/1/15) the molecular weight rose with increase in [M] /[Ni] ratio and 3—9 chains were produced per nickel atom. It was observed that as molecular weight increased so the cis content of the polymer increased — from ca. 50% up to ca. 90% [292]. 

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