[threpwood]

Stolen from Wikipedia (Natrium and K):

Because potassium (K) reacts quickly with even traces of water, and its reaction products are nonvolatile, it is sometimes used alone, or as NaK (an alloy with sodium which is liquid at room temperature) to dry solvents prior to distillation. In this role, it serves as a potent desiccant.

NaK (usually pronounced "nack"), an alloy of sodium and potassium which is liquid at room temperature, is used as a heat-transfer medium. It can also be used as a desiccant for producing dry and air-free solvents.

About Molybdenum:

Because of its lower density and more stable price, molybdenum is implemented in the place of tungsten. Molybdenum can be implemented both as an alloying agent and as a flame-resistant coating for other metals. Although its melting point is 2623 °C, molybdenum rapidly oxidizes at temperatures above 760 °C, making it better-suited for use in vacuum environments.

Molybdenum disulphide (MoS2) is used as a lubricant and an anti-corrosion agent. It forms strong films on metallic surfaces, and is highly resistant to both extreme temperatures and high pressure. Sodium molybdate is a bright orange pigment used with ceramics and plastics. Molybdenum trioxide (MoO3) is used as an adhesive between enamels and metals. Molybdenum powder is used as a fertilizer for some plants, such as cauliflower.