Chemical element of metals. Cu comes from Cuprum, Fe comes from Ferrum, Ag from Argentum. The symbols were not followed by a period (full stop) as with abbreviations. Later chemical elements were also assigned unique chemical symbols, based on the name of the element, but not necessarily in English. For example, sodium has the chemical symbol 'Na' after the Latin "natrium". The same applies to "W" (wolfram) for tungsten, "Fe" (ferrum) for iron, "Hg" (hydrargyrum) for mercury, "Sn" (stannum) for tin, "K" (kalium) for potassium, "Au" (aurum) for gold, "Ag" (argentum) for silver, "Pb" (plumbum) for lead, "Cu" (cuprum) for copper, and
Potassium chromate Potassium chromate Potassium chromate is the inorganic compound with the formula (KCrO). This yellow solid is the potassium salt of the chromate anion. It is a common laboratory chemical, whereas sodium chromate is important industrially. It is a class two carcinogen as it contains hexavalent chromium. Two crystalline forms are known, both being very similar to the corresponding potassium sulfate. Orthorhombic β-KCrO is the common form, but it converts to an α-form above 66 °C. These structures are complex, although the sulfate adopts the typical tetrahedral geometry. It is prepared by treating potassium dichromate with potassium hydroxide. In solution, the