Synthesis of the Elements

Tantalum Nitrides. Tantalum nitride [12033-62-4] TaN, is produced by direct synthesis of the elements at 1100°C. Very pure TaN has been produced by spontaneous reaction of lithium amide, L1NH2, and TaCl ( )- The compound is often added to cermets in 3—18 wt %. Ta N [12033-94-2] is used as a red pigment in plastics and paints (78). 

E. M. Burbidge, G. R. Burbidge, W. A. Fowler and F. Hoyle, Synthesis of the elements in stars. Rev. Mod. Rhys. 29, 547-650 (1957). This is the definitive review on which all later work has been based. 

Schematic representation uf the main features of the curve of cosmic abundances shown in Fig. 1.1, labelled according tn the various stellar reactions considered to be re.sponsible for the synthesis of the elements. (After E. M. Burbidge et...

The well-known textbook General Chemistry by Atkins and Beran (1992) starts by telling the reader that the cradle of chemistry lies in the stars. One can hardly think of a better way of emphasising the role of cosmochemistry. The synthesis of the elements, which are now logically ordered in the periodic table, can be divided into three stages, which are separated in both time and space ... 

Table 2.2 lists the most important syntheses occurring in the stars. The main products include the bioelements C, O, N and S. The synthesis of the elements began in the initial phase after the big bang, with that of the proton and the helium nucleus. These continue to be formed in the further development of the stars. The stable nuclide 4He was the starting material for subsequent nuclear syntheses. Carbon-12 can be formed in a triple a-process, i.e., one in which three helium... 

The dragon rears up, and spreads its vast pinions. The Earth falls away as you are borne up into the sky, ascending into heaven upon the living synthesis of the elements ... 

Almost all of the elements heavier than He are synthesized in the interiors of stars. The work of Burbidge et al. (1957) gives the theoretical framework for the synthesis of the elements. The experimental evidence of active nucleosynthesis came from the discovery of the unstable nuclei of technetium in the spectra of red giants (Merrill 1952). The solar elemental and isotopic abundances which are taken from the primitive carbonaceous chondrites constitute the guidelines for testing such models (Anders and Grevesse 1989). A minimum of eight basic processes are required to reproduce the observed compositions. Nucleosynthetic... 

Burbidge EM, Burbidge GR, Fowler WA, Hoyle F (1957) Synthesis of the elements in stars. Rev Mod Phys 29 547-630... 

Meitnerium - the atomic number is 109 and the chemical symbol is Mt. The name derives from the Austrian physicist Lise Meitner , who had discovered the element, protactinium. The first synthesis of the element Meitnerium is credited to German physicists from the GSI (Center for Heavy-Ion Research) lab at Darmstadt, Germany under Gunther Miinzenberg, in 1982 using the nuclear reaction ° Bi ( Fe, n) Mt. The longest half-life associated with this unstable element is 0.07 second Mt. 

Wallerstein, G., Iben, I. Jr., Parker, P. et al. (1997) Synthesis of the elements in stars forty years of progress. Reviews... 

Already many more elements have been synthesized than could be predicted in the early 1960s. Higher neutron-flux reactors could make the necessary amounts of the heavier transuranium elements needed for synthesis of the elements beyond 112. Much will depend upon whether the more neutron-rich isotopes with longer half-lives, essential for any study of chemical properties, can be made. The only safe prediction is the unpredictability of this area. 

Direct synthesis of the elemental constituents in evacuated quartz ampoules was used in most reported cases. The ampoules with the mixtures of elements were heated to different preset maximum temperature, for example 1420 K, and were kept at this temperature for a few hours. Afterward, the ampoules were cooled slowly to a respective annealing temperature, for example 870 K, and annealed at this temperature for many hours. In some cases, the flux method was used. Detailed experimental conditions can be found in the original cited papers. 

If more relativistic particles are present, gef f increases and the universe would expand faster so that, at fixed T, the universe would be younger. Since the synthesis of the elements in the expanding universe involves a competition between reaction rates and the universal expansion rate, gef j will play a key role in determining the BBN-predicted primordial abundances. 

A final aspect to the fitness of proteins relates to their evolutionary accessibility, especially in the early stages of cellular evolution, that he close to the origin of life. Henderson makes the point that in the case of water and carbonic acid In places where life is possible the primary constituents [water and carbonic acid] are necessarily and automatically formed in vast amounts by the cosmic process (1913, p. 268). Intriguingly, many of the twenty proteinaceous amino acids - out of which the folds are constructed - are among the commonest amino acids foimd in meteorites and the easiest amino acids to generate in prebiotic syntheses (Denton et al., 2002). Remarkably, the folds - so fit in so many other ways - are not so many steps removed from the synthesis of the elements in the stars, a witness to the fitness of matter for the evolution of protein-based life. 

Radioactive decay is a statistical process, there being nothing in any nucleus that allows us to predict when it will decay. The probability of decay in a given time interval is the only thing that can be determined, and this appears to be entirely constant in time and (except in the case of electron capture) unaffected by temperature, pressure or the chemical state of an atom. The probability is normally expressed as a half-life, the time taken for half of a sample to decay. Half-lives can vary from a fraction of a second to billions of years. Some naturally occurring radioactive elements on Earth have very long half-lives and are effectively left over from the synthesis of the elements before... 

The text is based on a series of six lectures given at the 2008 Kodai School on Synthesis of the Elements in Stars1 and on a more extended course given in the University of St Andrews and Trinity College, Dublin over a period of some twenty years. At Kodaikanal, the core material comprised four lectures. Two more advanced lectures covered horizontal-branch stars (Sect. 14) and hydrogen-deficient stars (Sect. 15). Development of the core material was originally drawn from several seminal texts [1, 2, 3,4, 5, 6, 7, 8, 9]. Section 15 and parts of Sect. 14 are based on [10,11]. 

AIK warmly thanks the organisers of the Kodai School on Synthesis of the Elements in Stars for the hospitality and the opportunity to attend and give lectures at the school. AIK also thanks John Lattanzio, Maria Lugaro, Simon Campbell, Peter Wood, Pilar Gil-Pons, Lionel Siess, and Mark van Raai for discussions and/or material that helped in the preparation of the lecture notes given at the School. She thanks Robin Humble, Ross Church, and Maria Lugaro for help with proof-reading her lecture notes. 

---