Discuss the occurrence, extraction and properties of the following elements. (a) Molybdenum (b) Palladium

Molybdenum (Mo) is a metallic element that enjoys a widespread presence across the globe but typically doesn't occur naturally in its metallic state. Rather, it's found in various minerals that provide pivotal sources for its extraction. The primary ore is molybdenite ((MoS_2)), notable for its distinct bluish hue and metallic luster. Other sources include powellite ((CaMoO_4)) and wulfenite ((PbMoO_4)), which can be identified by their bright colors and crystalline forms.

While the exact occurrence of these ores can vary, they are often located in mountainous regions and are associated with the mining of other metals, such as copper. Hence, large-scale mining operations for copper may also yield considerable quantities of molybdenum, facilitating the economic viability of its extraction. It's truly fascinating how molybdenum is so intricately intertwined with other mineral deposits within the Earth's crust.

Imagine a metal that can stand up to extreme temperatures without melting away—molybdenum is just that, boasting an impressive melting point of about 2623°C ((4753°F)), which grants it a key role in high-temperature applications and machinery. Its noble silver-gray appearance not only adds to its visual appeal but also hints at its impressive resistance to corrosion and oxidation.

Durability and Versatility

Molybdenum's ductility allows it to be drawn into fine wires or expanded into thin sheets without losing its integrity. Its strength and hardness don't compromise its ability to conduct electricity and heat, making it a versatile component in electrical contacts, filaments, and other high-tech applications. Furthermore, this metal is often a go-to choice for reinforcing steel, contributing to tougher and more resilient alloys used in construction, transportation, and military applications. The utility of molybdenum extends to the realm of aerospace and nuclear reactors, as its properties align well with the demands for durability and thermal resistance in such advanced fields.

Palladium, a precious metal with a luster that resembles the moonlight, belongs to the platinum group metals (PGMs) and has a relatively scattered presence in the Earth's crust. The elusive nature of palladium bearing ores means it's primarily sourced as a by-product from nickel-copper deposits. Geologically, it's more commonly found associated with other PGMs, nestled within layers of other minerals.

Global Distribution

Significant palladium deposits have been discovered in regions such as the Norilsk in Russia and the Bushveld Complex in South Africa. The extraction process relies on the intention to mine for other metals, such as nickel and copper, and due to this coupling, the geographical distribution of palladium mirrors that of these base metals. And so, we find the main producers are not only South Africa and Russia but also Canada and the United States, all of which contribute to the dynamic and often fluctuating market of this ethereal metal.

Palladium, a silvery-white metal, stands out for its exceptional luster and the ability to resist tarnishing in air under normal conditions, giving it a perennial brilliance. Highly pliable and malleable, it can be worked into intricate forms without breaking, a property that endears it to jewelers and watchmakers.

A Reaction with Hydrogen

One of the most unique aspects of palladium is its capacity to absorb hydrogen at room temperature, swelling in volume but not compromising its structural integrity. This absorption ability is more than just a scientific curiosity; it has practical implications, particularly in the field of hydrogen storage and purification technologies. Furthermore, palladium stands firm against various chemical erosions, making it indispensable in sectors like dentistry and electronic manufacturing. Its role in catalytic converters of automobiles is well-known, as it helps to transform hazardous emissions into less harmful substances, mirroring its precious nature through its application to environmental protection.