Cerium triiodide

Lanthanum and cerium triiodide, Lais and Cels, when reduced with strontium or barium or with the pseudo alkaline-earth metals neodymiiun, samarium, and emopium, yield ARl4-type iodides, A = Sr, Ba, Nd, Sm, Eu R = La, Ce. These are built from square-antiprismatic [Mis] polyhedra sharing common faces to columns running parallel [100] (Figure 9). Although these iodides have one excess electron per formula unit, e.g., (Ba +)(La +)(e )(I )4,... 

Mattausch, H. et al Angew. Chem. (Int.), 1998, 37(4), 499 The MISi compounds of Lanthanum, Cerium and Praseodymium, and two slightly less iodinated lanthanum derivatives were prepared by fusing stoichiometric mixtures of the triiodides, the metal and silicon. They ignite violently on contact with water. 

Diode array spectrophotometers can be especially useful because a complete spectrum can be collected in a short interval of time, making it possible to follow several species in a single experiment by taking repeated spectra. Also, several diode array instruments come with an open sample compartment, which makes it relatively easy to construct a flow reactor that can be placed in the light path of the instrument. The metal ion catalysts used in the BZ system absorb in the visible spectrum, so that UV/vis studies of the cerium-catalyzed or ferroin-catalyzed reaction are easy to perform. Iodine is another strongly absorbing species that is found in a number of chemical oscillators. Frequently, iodide ion is present as well, and the system is monitored at the iodine-triiodide isosbestic point at 471 nm. 

Conjugative reductions with lanthanides other than cerium In systems using lanthanides other than cerium (which is too insoluble in THF to be effective), samarium triiodide or erbium trichloride demonstrated similar lanthanide ion control of selective reductions (Gemal and Luche, 1981a) this was in... 

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