25Mn

Manganese

Transition metalsolidblock d

A steelmaking essential used as pigment 30,000 years before anyone knew it was an element, and the atom that splits water in photosynthesis.

Atomic number	25
Standard atomic weight	54.938 g/mol ± 0.001
Group · period	7 · 4
Electron configuration	[Ar] 3d⁵ 4s²

About Manganese

The black outlines in the cave paintings at Lascaux and Chauvet are manganese oxides, ground and mixed by artists tens of thousands of years before Johan Gahn isolated the metal in 1774. Modern steelmaking cannot do without it: manganese scavenges oxygen and sulfur from the melt, and there is no cheap substitute, so essentially every tonne of steel contains some. Robert Hadfield's 1882 manganese steel, at 12–14% Mn, work-hardens under impact and is still used for rock crusher jaws and railway crossings. Manganese dioxide is the cathode in every alkaline cell you have ever thrown away. Biologically, the oxygen-evolving complex at the heart of photosystem II is a cluster of four manganese atoms and one calcium — the catalyst that has been splitting water and releasing the atmosphere's oxygen for over two billion years.

Use 54.938 g/mol in these solvers

Moles from Mass (n = m/M)

n = \frac{m}{M}

Opens with M = 54.938 g/mol already filled in

Gas Density from Molar Mass

\rho = \frac{PM}{RT}

Opens with M = 54.938 g/mol already filled in

Faraday's Law of Electrolysis (m = QM/nF)

m = \frac{Q M}{n F}

Opens with M = 54.938 g/mol already filled in

Ion Concentration as CaCO₃ Equivalent

C_{\mathrm{CaCO_3}} = C_{\mathrm{ion}} \times \frac{50.04}{\mathrm{EW}}

Opens with EW = 54.938 g/mol already filled in

Acid Feed to Reduce Alkalinity

\dot m = \frac{\Delta \mathrm{Alk} \, Q \times \frac{\mathrm{EW}}{50.04}}{p/100\%}

Opens with EW = 54.938 g/mol already filled in

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