Tungsten crucible is a kind of high-temperature container made of tungsten (W) or tungsten-based alloy as the main material, which is widely used in metallurgy, materials science, semiconductor, aerospace and other fields that require ultra-high temperature treatment. 

Like tungsten bars, tungsten sheet is a typical product of the transition metal tungsten, sharing highly similar thermal, mechanical, chemical, and electrical properties, and is widely used in industries such as machinery and semiconductors.

Like ammonium metatungstate (AMT), sodium metatungstate is an important compound of the transition metal tungsten. It is a polymeric metatungstate formed by acidifying an isotungstate solution, exhibiting excellent physicochemical properties and widely used in density separation studies in geology, soil science, and marine biology.

As a typical tungstic acid, yellow tungstic acid generally refers to a transition metal compound with a 1:1 ratio of tungsten trioxide (WO₃) to water (H₂O). It consists of one tungsten atom, two hydrogen atoms, and four oxygen atoms, forming a pale yellow crystal or powder. It is a hydrated tungsten oxide, with the English name Yellow Tungstic Acid, a molecular formula of H₂WO₄ or WO₃·H₂O, and a molecular weight of 249.86.