Polonides

Beryllium sulfide, BeS beryllium selenide, BeSe beryllium telluride, BeTe beryllium polonide, BePo magnesium sulfide, MgS magnesium selenide, MgSe magnesium telluride, MgTe calcium sulfide, CaS (oldhamite) calcium selenide, CaSe calcium telluride, CaTe strontium sulfide, SrS strontium selenide, SrSe barium sulfide, BaS barium selenide, BaSe barium hydrosulfide, Ba(HS)2 barium hydrosulfide tetrahydrate, Ba(HS)2 H20. 

Zinc sulfide, ZnS, sphalerite (zinc blende) zinc sulfide, ZnS, wurtzite zinc selenide, ZnSe zinc telluride, ZnTe, cubic zinc telluride, ZnTe, hexagonal zinc polonide, ZnPo zinc aluminum selenide, ZnAl2Se4 zinc indium selenide, ZnIn2Se4 zinc indium telluride, Znhi2Te4. 

A number of polonides have been prepared by heating the elements together at relatively low temperatures (300°-400°C) all are grey or grey-... 

These compounds have only been studied on the trace scale. An ether soluble polonium dibenzyl is reported (80, 118) to be formed by the action of dimethylphenylbenzy 1-ammonium chloride on sodium polonide/telluride mixtures in water saturated with hydrogen. The dimethyl was prepared in the same way, but with dimethyl sulfate (118) and may also be formed in... 

Although Po is distinctly metallic in some ways, [e.g., it forms saltlike Po11 and PoIV compounds such as PoCl2, PoBr2, Po(S04)2, and Po(Cr04)2] it also shows nonmetal characteristics by forming numerous polonides (MPo), which are often isostructural with tellurides and appear to be fairly ionic. 

The selenides and tellurides are similar to the sulfides, being preparable from ammonia solutions of the alkali metals. They are water-soluble yet partially hydrolyzed like the sulfides, but are more susceptible to oxidation back to the element. Not every member of the class M cSe3,/Te3, has been fully investigated, but the many that have promise few surprises see Selenium Inorganic Chemistry and Tellurium Inorganic Chemistry). The polonides are similar, and also have their own article see Polonium Inorganic Chemistry). 

By analogy with tellurium, which forms tellurides, the existence of polonides should be expected. Soluble tellurides, such as sodium telluride, are extremely sensitive to oxidation. Especially in solution, they revert rapidly to elemental tellurium. Because of its greater metallic character, polonides should oxidize even more rapidly than tellurides. Nevertheless, evidence has been presented for the existence of a number of polonides. 

Ethyl radicals, C2H5-, have been reported to assist in the gas-phase transport of the isotopes Po and " Po. One interpretation of this phenomenon suggests the formation of diethyl polonide. However, an alternate explanation involves the dissociation of (C2H5)2Po into volatile H2P0 and ethylene. 

Among the organopolonium compounds arising from the /3-decay of are the diaryl polonides, PoAr2 ... 

Diaryl polonides are converted to the dibromides when they undergo reaction with Ar2TeBr2, Essentially, this is an oxidation reaction in which Po is oxidized from Po to Po and tellurium is reduced from Te to Te. Also, diaryl polonides add elemental bromine to form the dibromides. Thus, treatment of (C9Hu)2Po or (q -CioH7)2Po in benzene with bromine yields the dibromides. They can be precipitated by the addition of petroleum ether and recrystallized from benzene/petroleum ether. In a manner parallel to that just described, p-tolyl and Q -naphthylpolonium diiodides, Ar2Pol2, have been obtained by the addition of I2 to the respective diaryl polonides. 

H2Po H2Po, dihydrogen polonide H2Po = [PoH2], polane (parent hydride name), dihydridopolonium ... 

Selenium, Te and Po combine directly with most elements, though less readily than do O and S. The most stable compounds are (a) the selenides, tellurides and polonides (M ) formed with the strongly positive elements of Groups 1, 2 and the lanthanides, and (b) the compounds with the electronegative elements O, F and Cl in which the oxidation states are 4-2, 4-4 and... 

The reactions of polonium vapour with both Main-group and Transition-group IV elements have been studied. Polonium vapour did not react with Si, Ta, or Zr carbides, but did react with tin at 370 °C to give a tin polonide, which dissociated at 670 °C to the elements. 

---