Osmium, a group 8 d-block transition metal discovered in 1803 by the English chemist Smithson Tennant, is the rarest of the stable elements. Concentrations in the Earth’s crust are around 50 parts per trillion. The metal is found in nature uncombinrd or alloyed with its neighbour, iridium, in the alloys iridosmine or osmiridium. Around 500Kg

Xenon (Xe, Element 54) Xenon, from the Greek for ‘stranger’ is a colourless, odourless group 18 noble gas. Discovered in 1898 in London by William Ramsay, xenon is produced commercially by the fractional distillation of liquid air and is isolated as a by-product of the cryogenic production of oxygen and nitrogen. The concentration in the

Vanadium (V, Element 23) Vanadium, a group 5 transition metal, discovered in 1801 by Andres Manuel del Rio, occurs naturally as a component of vanadinite (Pb5(VO4)3Cl), one of the main industrial ores used as a source of the metal. Over 60 ores are known, with 70-80 thousand tonnes of ore mined globally each year, producing