Manganese
Manganese (Mn, atomic number 25) is a Period 4 transition metal (d-block, 54.938 u). Indispensable biological cofactor: the cubane Mn₄CaO₅ cluster in Photosystem II catalyzes the four-electron oxidation of water into atmospheric O₂, and mitochondrial
Manganese is a chemical element on the periodic table with the atomic symbol Mn, atomic number 25, and standard atomic weight 54.938 u. Classified as a Transition Metal within Group 7 and Period 4 (d-block), manganese possesses a ground-state electron configuration of [Ar] 3d5 4s2 distributed across 4 concentric Bohr electron shells (2 · 8 · 13 · 2) with 2 outer-shell electrons. Indispensable biological cofactor: the cubane Mn₄CaO₅ cluster in Photosystem II catalyzes the four-electron oxidation of water into atmospheric O₂, and mitochondrial Mn-SOD detoxifies superoxide radicals.
⚛️ Interactive Periodic Table Lab: Explore Manganese (Mn, Z = 25) in the CRV Science Dynamic Periodic Table & Bohr Orbital Lab to visualize its animated 2 · 8 · 13 · 2 electron shells, simulate live phase transitions from 0 K to 6,000 K, and compare periodic heatmaps across all 118 IUPAC elements.
Atomic Structure and Periodic Trends: How Do Quantum Orbitals Define Manganese?
Electron Shell Architecture and Ground-State Configuration
A neutral atom of manganese contains 25 protons in its atomic nucleus balanced by 25 electrons occupying quantized atomic orbitals. In the Bohr-Sommerfeld and quantum-mechanical orbital models, these electrons populate 4 principal energy shells (K (n=1): 2e−, L (n=2): 8e−, M (n=3): 13e−, N (n=4): 2e−), terminating in the four-lobed d-orbital manifold (azimuthal quantum number l = 2) with ground-state configuration [Ar] 3d5 4s2. Removing the most loosely bound valence electron from an isolated gaseous manganese atom requires a first ionization energy of 717 kJ/mol, while its tendency to attract shared bonding electrons is quantified by a Pauling electronegativity of 1.55.
Periodic Table Position and Neighboring Elements
Within the periodic table, Manganese occupies Period 4, Group 7 of the d-block (Transition Metals). Along Period 4, it is flanked by Chromium (Cr, Z = 24) and Iron (Fe, Z = 26). Vertically within its periodic family, Manganese shares valence orbital symmetry and homologous chemical trends with Technetium (Tc), Rhenium (Re), Bohrium (Bh). Learners can interactively compare Manganese's orbital radii, ionization energy, and Pauling electronegativity against all neighboring elements in the Dynamic Periodic Table Lab.
Physical and Thermodynamic Properties: How Does Manganese Behave Across Temperature Regimes?
Standard Phase, Melting Point, and Boiling Point Dynamics
At standard ambient temperature and pressure (298.15 K / 25 °C, 1 atm), elemental manganese exists as a crystalline solid. As thermal energy increases, its crystal or molecular lattice undergoes solid-to-liquid fusion at a melting point of 1,519 K (+1245.85 °C / +2274.5 °F) and transitions to the vapor phase at a normal boiling point of 2,334 K (+2060.85 °C / +3741.5 °F), spanning a liquid thermodynamic range of 815 K. In the CRV Science Dynamic Periodic Table, dragging the live temperature slider between absolute zero (0 K) and solar-photosphere temperatures (6,000 K) dynamically tracks Manganese's state transitions in real time alongside enthalpy and entropy phase equilibria.
Quantitative Atomic and Thermodynamic Parameter Matrix
| Parameter | Quantitative Value / Formula | Physical / Quantum Basis | Comparative Context in Group 7 / Period 4 |
|---|---|---|---|
| Atomic Number & Symbol | Z = 25 (Mn) | 25 nuclear protons; nuclear charge +25e | Located in Period 4, Group 7 (d-block) |
| Standard Atomic Weight | 54.938 u (g/mol) | Abundance-weighted isotopic nucleon mass | ~30 neutrons in dominant/reference mass number |
| Electron Configuration | [Ar] 3d5 4s2 | Shells: 2 · 8 · 13 · 2 (2 outer-shell e−) | Transition Metals valence orbital architecture |
| Electronegativity & Ionization | χ = 1.55; IE1 = 717 kJ/mol | Pauling bond polarity scale & first valence ionization enthalpy | Governs covalent vs. ionic bond character |
| Melting & Boiling Points | MP: 1519 K; BP: 2334 K | Cohesive lattice energy and intermolecular forces | STP (298 K) phase: SOLID (Liquid range: 815 K) |
| Principal Oxidation States | +2, +4, +7 | Valence electron donation, sharing, or acceptance | Discovered / First Isolated: 1774 |
Chemical Reactivity, Bonding, and Oxidation States: How Does Manganese Form Compounds?
Characteristic Oxidation States and Coordination Chemistry
As a d-block transition metal, partially filled (n−1)d orbitals lie close in energy to the outermost ns subshell, enabling variable oxidation states, d–d electronic transitions, coordination complex formation, and heterogeneous or metalloenzymatic redox catalysis. In chemical compounds, manganese exhibits characteristic oxidation states of +2, +4, +7. Depending on the electronegativity difference (Δχ) of its bonding partners—such as Oxygen (χ = 3.44), Fluorine (χ = 3.98), Chlorine (χ = 3.16), Nitrogen (χ = 3.04), Carbon (χ = 2.55), or Hydrogen (χ = 2.20)—manganese forms redox-specific oxides, halides, hydrides, or coordination complexes governed by Gibbs free energy (ΔG = ΔH − TΔS).
Nucleosynthesis, Discovery History, and Elemental Origins
First identified or isolated in 1774, Manganese carries a distinct cosmological and geochemical signature. As an element with atomic number Z ≤ 26, manganese is forged exothermically inside stars or via cosmic nucleosynthesis before being dispersed into protoplanetary nebulae.
Biological Role and Scientific Applications: Why Is Manganese Important in Nature and Technology?
Biochemical Classification: Essential Trace Cofactor
In comparative biochemistry and systems physiology, Manganese is classified as Essential Trace Cofactor. Catalytic transition metal or trace nonmetal required in metalloenzyme active sites (redox catalysis, O2 transport, hormone synthesis). Across terrestrial and marine ecosystems, its chemical speciation interacts with photosynthesis, enzymes, electron transport chain, oxidative phosphorylation, reactive oxygen species.
Key Mechanistic Functions and Technological Uses
Indispensable biological cofactor: the cubane Mn₄CaO₅ cluster in Photosystem II catalyzes the four-electron oxidation of water into atmospheric O₂, and mitochondrial Mn-SOD detoxifies superoxide radicals. Researchers and students can further investigate Manganese's functional role alongside all 118 elements by launching the Interactive Periodic Table & Element Detective Lab on CRV Science Learn.
Frequently Asked Scientific Questions
What is the electron configuration and valence shell structure of Manganese (Mn)?
Manganese (atomic number Z = 25) has the ground-state electron configuration [Ar] 3d5 4s2, distributing its 25 electrons across 4 shells as 2 · 8 · 13 · 2. Its outermost shell contains 2 electrons, placing Manganese in Group 7, Period 4 (d-block) as a member of the Transition Metals. You can watch these 25 electrons orbit the nucleus in real time in the Dynamic Periodic Table Bohr Lab.
What phase of matter is Manganese at room temperature, and when does it melt or boil?
At standard room temperature (298 K / 25 °C) and 1 atm pressure, Manganese is a crystalline solid. It melts at 1,519 K (+1245.85 °C / +2274.5 °F) and boils at 2,334 K (+2060.85 °C / +3741.5 °F). Using the 0–6,000 K temperature slider in the Interactive Periodic Table, you can observe Manganese's exact solid, liquid, and gas transitions relative to all other elements.
How does Manganese function in biochemistry, materials science, and technology?
Indispensable biological cofactor: the cubane Mn₄CaO₅ cluster in Photosystem II catalyzes the four-electron oxidation of water into atmospheric O₂, and mitochondrial Mn-SOD detoxifies superoxide radicals. In biological systems, it is categorized under Essential Trace Cofactor, with principal oxidation states of +2, +4, +7 and a first ionization energy of 717 kJ/mol.