Nickel chalcogenides

Ni3Sn2S2 Valence states of nickel, tin, and sulfur in the ternary chalcogenide, and " Sn Mossbauer investigations, XPS and band structure calculations... 

The Goodenough model (10) can account for the electrical properties of ternary rhodium chalcogenides of the type ARh2X4. The octa-hedrally coordinated Rh3+(4d6) has the low-spin configuration, and no contribution to the conductivity is made either by direct interaction of the cation t2g orbitals or by indirect e -anion s,pa interaction. This is not the case, however, for the M cations in the MRh2X4 compounds. For example, Ni2+(f2/e/) may contribute to metallic conductivity via formation of partially-filled or bands as a result of nickel e -anion s,pa interactions. Similar considerations apply to the other ternary rhodium chalcogenides. 

A nonactive electrode may include noble metals such as gold, silver, and platinum, the so-called sp-metals such as In, Ga, Cd, Bi, as well as transition (or d) metals such as nickel or cobalt. Carbon electrodes and semiconductors such as indium tin oxide [1], diamond [2], and conducting polymers may fall into the category of nonactive electrodes in appropriate solutions, as do composite materials that contain metal oxides or chalcogenides. The behavior of active electrodes in nonaqueous solution is discussed separately in the next chapter. 

Chalcogenides Solid-state Chemistry Copper Enzymes in Denitrification Copper Hemocyanin/Tyrosinase Models Copper Proteins Oxidases Copper Proteins with Dinuclear Active Sites Copper Proteins with Type 1 Sites Copper Proteins with Type 2 Sites Iron Sulfitf Models of Protein Active Sites Iron-Snlfiir Proteins Nickel Enzymes Cofactors Nickel Models of Protein Active Sites Polynuclear Organometallic Cluster Complexes. 

Solid chalcogenides are formed by all metallic elements and by many nonmetals. Only with the most electropositive metals do they commonly have the same structures as oxides (see Topics D3 and D4). With transition metals, compounds MX (which are frequently of variable stoichiometry) have the nickel arsenide or similar structures in which metal-metal bonding is present. MX2... 

So-called ternary or mixed oxide systems based on the rock salt structure are well established. Thus LiFe02 exists both in a disordered form in which Li and Fe are randomly distributed on the metal sites, and as an ordered variant with tetragonal symmetry. Rhombohedral distortions are found for LiNi02, LiV02, and NaFe02 in which the cations are ordered on different sublattices. The HCP counterpart of the sodium chloride structure, the so-called Nickel Arsenide stucture (5ee Chalcogenides Solid-state Chewistr, is found only for the heavier members of the Oxygen family. 

---