Sulfides magnetic susceptibilities

A dramatic decrease in the magnitude of the magnetic susceptibility anisotropy is observed on going from thiirane to the open-chain analog, dimethyl sulfide, and has been attributed to non-local or ring-current effects (70JCP(52)5291). The decrease also is observed to a somewhat lesser extent in oxirane relative to dimethyl ether. 

Another, more direct, indication is obtained from the work of Dilke, Eley, and Max ted (85), who found from the change in magnetic susceptibility of palladium on adsorption of dimethylsulfide that an electron of the sulfide had entered the d band of the metal. As we saw in Sec. V,8,b, a coordinate link is formed in this case. 

Some properties of selected vanadium compounds are listed in Table 1. Detailed solubility data are available (3), as are physical constants of other vanadium compounds (4). Included are the lattice energy of several metavanadates and the magnetic susceptibility of vanadium bromides, chlorides, fluorides, oxides, and sulfides (5). 

Other formally divalent compounds are the hydrides, MH2 (page 186), and the sulfides, MS, e.g., the golden-yellow LaS. These sulfides have the NaCl-type structure and are metallic conductors they are best formulated as M3+(S2 )e. Similarly the carbides, MC2, which give acetylene on hydrolysis, are M3 + (C2 )e. The sulfides of Sm, Eu and Yb are, however, in the M2 + state according to their magnetic susceptibilities. 

A second striking feature of the Amazon Fan sediments (gravity core GeoB 1514-6) is the occurrence of a pronounced maximum in magnetic susceptibility, located slightly above the zone of strong enrichment of iron sulfide minerals (Fig. 

The toxicity of an element such as sulfur is dependent on the presence, in the valency shell of the toxic element, of free electron pairs which are evidently necessary for the formation of the link with the catalyst. The toxicity—i.e., the power of forming a relatively strong chemisorptive bond—disappears if the structure of the molecule is of a shielded type in which this element is already associated with a completely shared electron octet. Thus, it appears (Maxted, 8) that the chemical bond by means of which the poison is linked to the metallic surface resembles the ordinary dative bond in which the poison is the donor. In the case of methyl sulhde adsorbed on palladium, indications have been obtained (Dilke, Eley, and Maxted, 9) by means of magnetic susceptibility measurements that electrons from the methyl sulfide enter the d-band of the adsorbing metal to give a coordinate link, the process being probably accompanied (Maxted, 10) by a filling up of the fractional deficiencies or holes in the d-band of the metal due to d- -band overlap which seem to be responmble for the catalytic activity of the transition metals (11). 

Rare earth monoselenide powders MSe are decomposed in air at room temperature with liberation of H2Se, but less readily than the sulfides, see for example, landelli [1] for M = La to Nd, landelli [2] for M = Sm, and Guittard, Benacerraf [3] for M = Eu and Gd. Compacted specimens are relatively stable owing to the formation of a metal oxide film on the surface, Obolonchik, Mikhlina [4]. Dull black YbSe, when kept for some hours in air or moisture, did not change superficially however, its magnetic susceptibility increased markedly due to the formation of Yb , Senff, Klemm [5]. 

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