Thallium complexes, mono

Oxidation of ethylene to ethylene glycol and its mono- and diacetates has also been catalyzed by tellurium and thallium complexes in the presence of halides... 

A detailed, multimethod study of hydrated Tl(III) cyanide species in aqueous solution reveals that Tl(III) forms very strong complexes with cyanide ions (even stronger than halide-Tl(III) interactions)." " Formation of a series of Tl(III) complexes T1(CN) n= -4t) has been established, and the solution structures and stability constants were reported. The mono- and dicyano complexes [Tl(CN)(OH2)5] and [Tl(CN)2(OH2)4] show six-coordinate thallium centers, whereas Tl(CN)3(OH2) and [T1(CN)4] have four-coordinate T1(III) ions. 

Main and subgroup elements of the earlier rows often exhibit a dynamic equilibrium between different coordination numbers. Elements such as fluorine, chlorine, oxygen, etc., can donate one or two free electron pairs to vacant lower energy orbitals of these metal atoms. Fluorine can therefore act as a bifunctional bridging atom, and oxygen can even be mono- to tetrafunctional, according to its bond partner. In all these cases the coordination number is increased above normal. In the case of fluorine, fluorine bridge bonds exist, for example, in the anion of the complex between thallium fluoride and aluminum fluoride ... 

---