User:Axiosaurus/draft2

=Thallium chalcogenides= The thallium chalcogenides include all compounds of thallium with the chalcogen elements, oxygen, sulfur, selenium and tellurium. (Polonium is excluded as little is known about its compounds with thallium). Some compounds that have been reported have not been substantiated by later researchers. The list of compounds below shows compounds that have been reported, and those compounds that have not had their structure determined, or whose existence has not been confirmed by the latest structural investigations, are in italics. In contrast to the indium chalcogenides the thallium(I) compounds are well characterised, there are no compounds with a Tl22+ unit, and the only genuine thallium(III) chalcogenide is the oxide, Tl2O3

Tl2O, Tl2S, Tl2Se, Tl2Te
All of these compounds are thallium(I) compounds. There are all black with a metallic appearance. Tl2S occurs as the mineral carlinite and has been used in infrared detectors. Tl2Se has metallic conductivity, and is a semiconductor in the liquid phase. The structure of Tl2Te has been reinvestigated and is shown to be a new structure type related to Tl5Te3.

Tl5Se3, Tl5Te3
Tl5Se3 has the Cr5B3 structure. Tl5Te3 has a structure related to In5Bi3, and has been formulated as 9Tl+ Tl3+ 6Te2 &minus;

TlS, TlSe, TlTe
TlS and TlSe are both black mixed valence compounds containing thallium in oxidation states +1 and +3. For example TlS can be formulated Tl+ Tl3+ 2S2 &minus;. TlS has two crystalline forms, a tetragonal chain structure and a monoclinic layer structure. The room temperature monoclinic form is ferroelectric. . TlTe on the other hand is not a mixed valence compound but is a thallium(I) polytelluride, with a complex structure. TlTe is described as semimetallic.

Tl2O3, Tl2S3, Tl2Se3, Tl2Te3
Tl2O3 is the mineral avicennite. Its normal form has a bixbyite, Mn2O3, structure and the high pressure form has a corundum, α-Al2O3, structure. It is a degenerate n-type semiconductor. Tl2S3 and Tl2Se3 have both been reported in the past however they have not been confirmed. Tl2Te3 is a polytelluride with a complex structure

TlS2, Tl2S5, Tl2S9
These are all thallium(I) polysulfides.

=Gallium chalcogenides= The gallium chalcogenides include all compounds of gallium with the chalcogen elements, oxygen, sulfur, selenium and tellurium. (Polonium is excluded as little is known about its compounds with gallium). Some compounds that were reported and have found their way into text books have not been substantiated by later researchers. The list of compounds below shows compounds that have been reported, and those compounds that have not had their structure determined, or whose existence has not been confirmed by the latest structural investigations, are in italics.