Group VIIIB

Only chalcogenide halides of palladium and platinum are mentioned in the literature. 

Thiele and co-workers (389) prepared the only known palladium chalcogenide halides, PdTel emd Pd Sels, by hydrothermal synthesis in HI (see Section II,D,2) at 300°C, starting with the elements. Crystalline PdzSels is better obtained by reaction of Pdlj with Se and an excess of iodine in a closed ampoule at 250°C (reaction time, 2 days). 

The brass-colored PdTel consists of Jahn-Teller distorted PdTe2/2l4/4 octahedra, which are interconnected by common edges and corners to afford a loose, spatial network. The compound is considered to be ionic, containing Pd and Te , although the observed diamagnetism, electronic conduction, and color suggest some metallic character. 

In the black, lustrous Pd Selj, four quadratic PdSei/als, entities are connected by a common Se to a Pd4Se2l4l4/2 group (see Fig. 27). These groups combine via common iodines to form corrugated layers. The formal oxidation state of Pd is 2 -l-. 

No platinum chalcogenide halides of invariable, exact, stoichiometric compositions are known. 

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Most metals active in cyclization belong to Group VIIIB and have either face-centered-cubic (fee) or hexagonal close packed (hep) crystal structure. 

Ca-M-Hand Sr-M-H Systems Where M = Group VIIIB Metal... 

The properties of some rare-earth binary alloys with platinum group metals are also important in view of the role they can play in the chain of preparing ternary hydrides. Many of the alloys of the series R-M, where R is a rare earth element and M is a Group VIIIB metal, have been investigated structurally and magnetically. The alloys with iridium all have cubic structures, whereas those... 

Table 5 contains the tetraazadiene-metal complexes reported to date. They all are derived from the Group VIIIB transition metals Fe, Co, Ni, Rh, Ir and Pt and have a 1/1 metal/R2N4 molar ratio (c-f. 59-65 in Figure 4). Exceptions are the nickel complexes which in addition to various 1/1 complexes173,174 also include 2/1 complexes Ni(R2N4)2 (66).175,176... 

Understandably, these compounds having cis CO groups do not undergo a Hofmann acid amide degradation to give the respective hydrido complexes. The stability of these Group VIIIB carbamoyl complexes increases in the order Fe, Ru, Os. 

We place hydrogen as the first element in the first period, along with helium. When helium was discovered, Mendeleev put it in the second period. We put the triads of iron, cobalt, and nickel ruthenium, rhodium and palladium and osmium, iridium, and platinum in group VIIIB, in the middle of the table. Mendeleev put them in group VIII. We also have two long groups, the lanthanides and actinides, that were a headache for Mendeleev. 

Green, Stone, and co-workers have done considerable work on HFA metal complexes. Most of their publications, of which the earlier ones were reviewed by Stone in 1972 (261), deal with low-valent group VIIIB elements. Two kinds of reactions are generally observed. 

Although Group VIIIb comprises further quadrupolar nuclei (e.g. 6iNi, ° Pd, their resonances remain to be studied... 

Group IVB [4) Group VB Group VB( GroupV0B(7) Group VIIIB(q... 

Group IVB (4) Group VB (5) Group VIB (6) Group VIIB (7) Group VIIIB (8) Group VIIIB (9) Group VIIIB (10)... 

The Group VIIIB (8, 9, and 10) metals illustrate well the point made previously that heavier congeners more readily assume higher oxidation states. Thus iron, cobalt, and nickel are effectively limited to +2 and +3 oxidation states, but all of then-congeners have reasonably stable higher oxidation states. 

Physical and Chemical Properties Cobalt (atomic number 27, atomic mass 58.9332, CAS Registry Number 7440-48-4) belongs to Group VIIIB of the transition ele-... 

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