Símbolo | Mn |
Número atómico | 25 |
Grupo | 7 (Familia del manganeso) |
Período | 4 |
Bloque | d |
Clasificación | Metal de transición |
Apariencia | Silvery metallic |
Color | Plata |
Número de protones | 25 p+ |
Número de neutrones | 30 n0 |
Número de electrones | 25 e- |
Fase en STP | Sólido |
Densidad | 7.21 g/cm3 |
Peso atómico | 54.938 u |
Punto de fusión | 1519 K 1245.85 °C 2274.53 °F |
Punto de ebullición | 2334 K 2060.85 °C 3741.53 °F |
Entalpía de vaporización | 219.74 kJ/mol |
Electronegatividad (Escala de Pauling) | 1.55 |
Afinidad electrónica | -50 kJ/mol |
Estado de oxidación | −3, −2, −1, 0, +1, +2, +3, +4, +5, +6, +7 (depending on the oxidation state, an acidic, basic, or amphoteric oxide) |
Energía de ionización |
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Descubrimiento | Carl Wilhelm Scheele (1774) |
Primer aislamiento | Johann Gottlieb Gahn (1774) |
Descubrimiento de manganeso Manganese compounds were used by Egyptian and Roman glassmakers, either to add to, or remove, color from glass. Use as "glassmakers soap" continued through the Middle Ages until modern times and is evident in 14th-century glass from Venice. Because it was used in glassmaking, manganese dioxide was available for experiments by alchemists, the first chemists. Ignatius Gottfried Kaim (1770) and Johann Glauber (17th century) discovered that manganese dioxide could be converted to permanganate, a useful laboratory reagent. By the mid-18th century, the Swedish chemist Carl Wilhelm Scheele used manganese dioxide to produce chlorine. By the mid-18th century, Carl Wilhelm Scheele used pyrolusite to produce chlorine. Scheele and others were aware that pyrolusite (now known to be manganese dioxide) contained a new element. Johan Gottlieb Gahn was the first to isolate an impure sample of manganese metal in 1774, which he did by reducing the dioxide with carbon. |