Nearly eight millennia ago the gaze of humankind was transfixed by the alluring yellow colour of gold. There was born the desire to transmute all base materials into gold. This signalled the origin of alchemy with its search for the Philosopher’s Stone, whose touch will transform materials into gold. The alchemists made many experiments. Though its practice was shrouded in superstitions and secrecy, these were the first tentative steps, which slowly gave rise to modern metallurgy and chemistry. Indeed the birth of modern science began from the misty origins of alchemy and the transition is best exemplified by Sir Isaac Newton, one of the greatest scientific minds, dabbling in alchemy.
Though we pride ourselves in rational science, the alluring promise of alchemy never left its attraction. Thus the modern nano-scientists like to term their craft as modern alchemy. The experiments on gold colloids by Michael Faraday showed that with changing size the same immutable gold can display different properties and most spectacularly different colours.
If one can pass from nano to giga and above, one will be drawn to the largest object, namely the universe itself. Nobody has done more than Carl Sagan to bring in a vivid fashion the cosmic alchemy that signalled the birth of the universe. In the Big Bang the fusion of hydrogen and helium led to carbon , oxygen and so on , until the cosmic fire was quenched by making that most stable nuclide of iron . Indeed the extraordinary abundance of iron is due to its nuclear stability. Then in a later event the supernovae explosions led to another bout of cosmic alchemy. These celestial fireworks led to the creation of the higher elements. Today we are poised to recreate these awesome events of the Big Bang in a 30 km circle straddling the borders of Switzerland and France
The story of the nuclear alchemy has often been narrated. Mendeleev’s periodic table goes from hydrogen to uranium with the atomic numbers going from 1 to 92. Yet four of these are not naturally occurring and had to be created by scientists by radioactive bombardment. While the four (Technetium , Francium , Astatine and Promethium) may only be curiosities with short half lives, they were the first invitations to make atoms beyond uranium. It is noteworthy that the seven metals of antiquity were bestowed with the planetary influences of the sun, the moon and then known five planets. Uranium signaled the return to this planetary obsession. Thus it is no surprise that elements 93 and 94 were called neptunium and plutonium
Plutonium- 239 was created by Glenn Seaborg in 1941. ( I happen to share my year of birth with this metal!). During 1965 to 1967 I was at the Lawrence Radiation Laboratory , where the mighty cyclotrons were built. This led Seaborg and colleagues to a glorious era of nuclear alchemy , where they created a host of actinides. This is best recognized by the names Seaborgium , Berkelium and Californium.
When I edited in June 2006 the Special Issue of Resonance dedicated to Prof Cyril Stanley Smith, I became fully aware of the fascinating contributions of metallurgists to plutonium – the modern equivalent of ancient gold. Readers are invited to savour the early achievements of metallurgists in the success of the Manhattan Project by reading the Special Issue. Without any prior data, the physical metallurgy of plutonium was established in a short span of time including alloying with Gallium.
The awesome power of Plutonium resides in the essential instability of its nuclide with 239 as the atomic weight. This was first tested in an atomic device, called the Trinity test in the deserts of Los Alamos. The power of the explosion made Robert Oppenheimer exclaim from the Bhagavad Gita . This famous quotation of “Brighter than a thousand suns” still reverberates around the world
Metallurgy can be taught in the most fascinating fashion using just plutonium. It has often been called the maverick metal. It shows allotropy in profusion existing in six different crystalline forms. It contracts on melting like ice. Its electronic properties again reveal that it teeters between itinerant electrons of actinides with lower atomic number and localized electrons of actinides with higher atomic number. It tarnishes very quickly in contrast to the immortal gold. It is self destructive as the internal radioactivity damages the lattice. The metallurgist, Siegfried Hecker, has made major contributions to the understanding of the nuances of plutonium metallurgy including its position in international relations.
Nevertheless these thousand suns of plutonium and the singular sun are attracting attention to an energy- starved world in the form of nuclear energy and solar energy. Indian metallurgy has many triumphs in the past, Today destiny beckons India once again. In 1951 Brahm Prakash sowed the seeds of India’s nuclear materials programme at the Indian Institute of Science. Together with C V Sundaram, seminal work was done on the separation of zirconium and hafnium. Then a host of IISc alumni moved to the atomic energy programme at Mumbai and helped in a significant fashion in metals of interest including Uranium and Plutonium. One remembers the early contributions of P R Roy , an alumnus of B E College, Sibpur. Plutonium activity then shifted to the South with the commissioning of the Indira Gandhi Centre for Atomic Research, Kalpakkam. Here again the contributions of C V Sundaram and Placid Rodriguez are outstanding.
Today we stand at a nuclear dawn. India is poised to exert world leadership in taming this wild metal so that its destructive power is channelised to constructive electrical energy production. It gives me much pride to recognize that leading this effort is Baldev Raj, whom I have the privilege of having as a student.
Near the Mahabalipurm sands where once Sivakami danced, we will see the dance of neutrons and swirling liquid sodium. When the energy from the Fast Breeder Prototype Reactor feeds 500 MW into the nation’s grid, we will have kept our tryst with destiny.