Tellurium atoms

Manufacture and Recovery. Electrolytic copper refinery slimes are the principal source of selenium and its sister element, tellurium, atomic numbers 34 and 52, respectively. Electrolytic copper refinery slimes are those constituents in the copper anode which are not solubilized during the refining process and ultimately accumulate in the bottom of the electrorefining tank. These slimes are periodically recovered and processed for their metal values. Slimes generated by the refining of primary copper, copper produced from ores and concentrates, generally contain from 5—25% selenium and 2—10% tellurium. 

The reaction of Te(N3)4 with ionic azides generates the [Te(N3)6] anion (Eq. 5.8). The stmeture of this anion is strongly distorted from octahedral by the stereochemically active lone pair on the tellurium atom, which gives rise to substantial differences in the Te-N bond lengths. Eour of these bonds are in the range 2.09-2.24 A, cf. [Te(N3)5] ,... 

As in phenoxatellurines, phenothiatellurine [95AHC(63)1] and benzotellura-zoles (89KGS757), 10-alkylphenotellurazines 43 react with elemental sulfur at elevated temperature by replacing the ring tellurium atom by sulfur (85KGS757). The yield of this reaction is about 50%. 

The first compound containing a telluroazepine ring, ll-(4-methylphenyl) dibenzo[d,/][l,4]telluroazepine 62 was obtained in 21% yield upon heating p-xylene solution of 9-azido-9-(4-methylphenyl)telluroxanthene at 130-140°C (87KGS279). Other products of this pyrolitic process are the imine 63 (32% yield) and phenanthridine 64 (21% yield). Formation of the latter implies extrusion of the tellurium atom from dibenzotelluroazepine 62. 

The compound 92 is extremely light-sensitive. Under the action of phosphites or compounds with multiple bonds, it readily eliminates a tellurium atom and thus may be considered as a synthetic equivalent of the heterodiene 93a. 

On treatment with sodium ethanolate or aqueous ethanolic KOH, 2,5-diaza-1,6-dioxa-6<2-tellurapentalenes 97 eliminates a tellurium atom to give l,2,3-triketone... 

Under normal conditions an atom in elemental tellurium has coordination number 2 + 4. It has been known for a long time that pressure causes the interatomic distances to approximate each other until finally every tellurium atom has six equidistant neighboring atoms at 297 pm the structure (now called Te-IV) corresponds to /3-polonium. However, before this is attained, two other modifications (Te-II and Te-III) that are out of the ordinary appear at 4 GPa and 7 GPa. Te-II contains parallel, linear chains that are mutually shifted in such a way that each Te atom has, in addition to its two neighboring atoms within the chain... 

Bicyclic Systems with Bridgehead (Ring Junction) Sulfur, Selenium, or Tellurium Atoms... 

There are no bicyclic systems known with one tellurium atom at the bridgehead position. 

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