Actinide elements Lanthanides

Elements in the s and p blocks of the table are referred to as typical elements whilst those in the d block are called transition elements and those in the/block are called actinides and lanthanides (or rare earth elements). 

Ion-exchange separations can also be made by the use of a polymer with exchangeable anions in this case, the lanthanide or actinide elements must be initially present as complex ions (11,12). The anion-exchange resins Dowex-1 (a copolymer of styrene and divinylben2ene with quaternary ammonium groups) and Amherlite IRA-400 (a quaternary ammonium polystyrene) have been used successfully. The order of elution is often the reverse of that from cationic-exchange resins. 

Table 3. Electronic Configurations for Gaseous Atoms of Lanthanide and Actinide Elements...

Table 9. Ionic Radii of Actinide and Lanthanide Elements...

Thus it can be seen that elements in and near the island of stabiHty based on element 114 can be predicted to have chemical properties as foUows. Element 114 should be a homologue of lead, that is, should be eka-lead, and element 112 should be eka-mercury, element 110 should be eka-platinum, etc (26,27). If there is an island of stabiHty at element 126, this element and its neighbors should have chemical properties like those of the actinide and lanthanide elements (26). 

There is no single best form of the periodic table since the choice depends on the purpose for which the table is used. Some forms emphasize chemical relations and valence, whereas others stress the electronic configuration of the elements or the dependence of the periods on the shells and subshells of the atomic structure. The most convenient form for our purpose is the so-called long form with separate panels for the lanthanide and actinide elements (see inside front cover). There has been a lively debate during the past decade as to the best numbering system to be used for the individual... 

The redox behaviour of Th, Pa and U is of the kind expected for d-transition elements which is why, prior to the 1940s, these elements were commonly placed respectively in groups 4, 5 and 6 of the periodic table. Behaviour obviously like that of the lanthanides is not evident until the second half of the series. However, even the early actinides resemble the lanthanides in showing close similarities with each other and gradual variations in properties, providing comparisons are restricted to those properties which do not entail a change in oxidation state. The smooth variation with atomic number found for stability constants, for instance, is like that of the lanthanides rather than the d-transition elements, as is the smooth variation in ionic radii noted in Fig. 31.4. This last factor is responsible for the close similarity in the structures of many actinide and lanthanide compounds especially noticeable in the 4-3 oxidation state for which... 

One name, more than any other, is associated with the actinide elements Glenn Seaborg (1912-1999). Between 1940 and 1957. Seaborg and his team at the University of California, Berkeley, prepared nine of these elements (at no. 94-102) for the first time. Moreover, in 1945 Seaborg made the revolutionary suggestion that the actinides, like the lanthanides, were filling an f sublevel. For these accomplishments, he received the 1951 Nobel Prize in chemistry. 

Unsubstituted bisphthalocyanines 2 are formed in the presence of several elements which exist in a stable oxidation state of + III or +IV such as titanium, zirconium, hafnium, indium and most of the lanthanide and actinide elements. 

Unusual oxidation states of some actinide and lanthanide elements. L. B. Asprey and B. B. Cunningham, Prog. Inorg. Chem., 1960, 2, 267-302 (245). 

Figure 3. The lattice parameter for the family of rock-salt structure actinide-antimonide compounds is shown where the line is for the corresponding lanthanide compounds. The metallic radii for the light actinide elements are plotted. The smooth line simply connects Ac to the heavy actinides. In both cases the smooth line represents the ideal tri-valent behavior.

Compounds containing group-lIB-transition-metal bonds arc characterized for almost every transition metal. Although there are more derivatives containing Hg than Zn or Cd, there is no difficulty in producing analogous compounds of each of these metals. No compound is known in which Zn, Cd or Hg is bonded to either lanthanide or actinide elements. 

Webb LM, Taylor DM, Williams DR. 1998. Computer modeling of the chemical speciation of lanthanide and actinide elements in the human gastrointestinal tract Mouth and stomach. Radiat Prot Dosim 79(l/4) 219-222. 

As the atomic number increases, so does the positive charge of the nucleus, and the electrons are bound with a higher energy. However, this increase is not linear. For example, the electrons in the d orbital of the third shell have a higher energy than those in the s orbital of the fourth shell, and hence the latter are filled first. The consequence is the unexpected behavior of the first ten transition elements. In the case of the actinides and lanthanides, even more inner orbitals are occupied. Nature is not so simple, but the scheme should help to visualize this complex structure. And if one can assign the electrons of an element, one is a step closer to successfully unraveling the mysteries of the Periodic Table. 

As to the first route, we started in 1969 (1) in investigating unconventional transition metal complexes of the 5 and 4f block elements of periodic table, e.g., actinides and lanthanides as catalysts for the polymerization of dienes (butadiene and isoprene) with an extremely high cis content. Even a small increase of cistacticity in the vicinity of 100% has an important effect on crystallization and consequently on elastomer processability and properties (2). The f-block elements have unique electronic and stereochemical characteristics and give the possibility of a participation of the f-electrons in the metal ligand bond. 

Lanthanide elements are /-block elements in which the 4 /-subshell is filling Ce through Lu. Actinide elements are in which the 5 /-subshell is filling Th through Lr. 

Asprey, L. B. and Cunningham, B. B., Unusual Oxidation States of Some Actinide and Lanthanide Elements. 2 267... 

Figure 5.13. Scheme of correspondence between the different lanthanide and actinide elements which may be assumed on the basis of several similarities and analogies in their chemical and alloying behaviours. 

Wish, L., E. C. Freiling and R. Bunney Ion-Exchange as a Separation Method. VIII. Relative Elution Position of Lanthanide and Actinide Elements with Lactic Acid Eluant at 87° C. J. Amer. chem. Soc. 76, 3444 (1954). 

Lawrencium is the last of the transuranic elements and the 15 th in the actinide series (there are 15 elements in the lanthanide series as well, assuming you start counting the series at the elements lanthanide and actinium, respectively.) It is assumed that lawrencium has some chemical and physical characteristics similar to lutetium, located just above it in the lanthanide series. It is also located at the bottom of the group 17 (VILA) elements, which makes it the heaviest of the halides. 

The actinide elements result from the Ailing up of the bf orbitals and are the analogs of the lanthanides (J). There is a close similarity between the trivalent 4/and 5/ions. However, the actinides differ from the lanthanides in... 

The review is divided into three sections, (i) the chemistry of scandium and yttrium, (ii) the chemistry of the lanthanide elements, further subdivided into a survey of lanthanide n.m.r. shift reagents and the general chemistry of the elements, and (iii) the chemistry of the actinide elements and uranyl and related compounds. 

Americium may be separated from other elements, particularly from the lanthanides or other actinide elements, by techniques involving oxidation, ion exchange and solvent extraction. One oxidation method involves precipitation of the metal in its trivalent state as oxalate (controlled precipitation). Alternatively, it may be separated by precipitating out lanthanide elements as fluorosilicates leaving americium in the solution. Americium may also he oxidized from trivalent to pentavalent state by hypochlorite in potassium carbonate solution. The product potassium americium (V) carbonate precipitates out. Curium and rare earth metals remain in the solution. An alternative approach is to oxidize Am3+ to Am022+ in dilute acid using peroxydisulfate. Am02 is soluble in fluoride solution, while trivalent curium and lanthanides are insoluble. 

Americium and other actinide elements may be separated from lanthanides by solvent extraction. Lithium chloride solution and an eight to nine carbon tertiary amine are used in the process. Americium is then separated from curium by the above methods. 

Molecular Interactions Reaction Kinetics Basic Spectroscopy X-ray Crystallography Lanthanide and Actinide Elements Maths for Chemists Bioinorganic Chemistry Chemistry of Solid Surfaces Biology for Chemists Multi-element NMR... 

---