Glossary
Allotropes
Some elements exist in several different structural forms, called allotropes. Each allotrope has different physical properties.
For more information on the Visual Elements image see the Uses and properties section below.
| Discovery date | 1774 |
| Discovered by | Johan Gottlieb Gahn |
| Origin of the name | The derivation of Manganese may have come from one of two routes: either from the Latin 'magnes', meaning magnet, or from the black magnesium oxide, 'magnesia nigra'. |
| Allotropes |
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Glossary
Group
A vertical column in the periodic table. Members of a group typically have similar properties and electron configurations in their outer shell.
Period
A horizontal row in the periodic table. The atomic number of each element increases by one, reading from left to right.
Block
Elements are organised into blocks by the orbital type in which the outer electrons are found. These blocks are named for the characteristic spectra they produce: sharp (s), principal (p), diffuse (d), and fundamental (f).
Atomic number
The number of protons in an atom.
Electron configuration
The arrangements of electrons above the last (closed shell) noble gas.
Melting point
The temperature at which the solid–liquid phase change occurs.
Boiling point
The temperature at which the liquid–gas phase change occurs.
Sublimation
The transition of a substance directly from the solid to the gas phase without passing through a liquid phase.
Density (g cm−3)
Density is the mass of a substance that would fill 1 cm3 at room temperature.
Relative atomic mass
The mass of an atom relative to that of carbon-12. This is approximately the sum of the number of protons and neutrons in the nucleus. Where more than one isotope exists, the value given is the abundance weighted average.
Isotopes
Atoms of the same element with different numbers of neutrons.
CAS number
The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems.
| Group | 7 | Melting point | 1246°C, 2275°F, 1519 K |
| Period | 4 | Boiling point | 2061°C, 3742°F, 2334 K |
| Block | d | Density (g cm−3) | 7.3 |
| Atomic number | 25 | Relative atomic mass | 54.938 |
| State at 20°C | Solid | Key isotopes | 55Mn |
| Electron configuration | [Ar] 3d54s2 | CAS number | 7439-96-5 |
| ChemSpider ID | 22372 | ChemSpider is a free chemical structure database | |
Glossary
Image explanation
Murray Robertson is the artist behind the images which make up Visual Elements. This is where the artist explains his interpretation of the element and the science behind the picture.
Appearance
The description of the element in its natural form.
Biological role
The role of the element in humans, animals and plants.
Natural abundance
Where the element is most commonly found in nature, and how it is sourced commercially.
History
History
Atomic radius, non-bonded
Half of the distance between two unbonded atoms of the same element when the electrostatic forces are balanced. These values were determined using several different methods.
Covalent radius
Half of the distance between two atoms within a single covalent bond. Values are given for typical oxidation number and coordination.
Electron affinity
The energy released when an electron is added to the neutral atom and a negative ion is formed.
Electronegativity (Pauling scale)
The tendency of an atom to attract electrons towards itself, expressed on a relative scale.
First ionisation energy
The minimum energy required to remove an electron from a neutral atom in its ground state.
Glossary
Common oxidation states
The oxidation state of an atom is a measure of the degree of oxidation of an atom. It is defined as being the charge that an atom would have if all bonds were ionic. Uncombined elements have an oxidation state of 0. The sum of the oxidation states within a compound or ion must equal the overall charge.
Isotopes
Atoms of the same element with different numbers of neutrons.
Key for isotopes
| Half life | ||
|---|---|---|
| y | years | |
| d | days | |
| h | hours | |
| m | minutes | |
| s | seconds | |
| Mode of decay | ||
| α | alpha particle emission | |
| β | negative beta (electron) emission | |
| β+ | positron emission | |
| EC | orbital electron capture | |
| sf | spontaneous fission | |
| ββ | double beta emission | |
| ECEC | double orbital electron capture | |
Glossary
Data for this section been provided by the British Geological Survey.
Relative supply risk
An integrated supply risk index from 1 (very low risk) to 10 (very high risk). This is calculated by combining the scores for crustal abundance, reserve distribution, production concentration, substitutability, recycling rate and political stability scores.
Crustal abundance (ppm)
The number of atoms of the element per 1 million atoms of the Earth’s crust.
Recycling rate
The percentage of a commodity which is recycled. A higher recycling rate may reduce risk to supply.
Substitutability
The availability of suitable substitutes for a given commodity.
High = substitution not possible or very difficult.
Medium = substitution is possible but there may be an economic and/or performance impact
Low = substitution is possible with little or no economic and/or performance impact
Production concentration
The percentage of an element produced in the top producing country. The higher the value, the larger risk there is to supply.
Reserve distribution
The percentage of the world reserves located in the country with the largest reserves. The higher the value, the larger risk there is to supply.
Political stability of top producer
A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators.
Political stability of top reserve holder
A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators.
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Glossary
Specific heat capacity (J kg−1 K−1)
Specific heat capacity is the amount of energy needed to change the temperature of a kilogram of a substance by 1 K.
Young's modulus
A measure of the stiffness of a substance. It provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain.
Shear modulus
A measure of how difficult it is to deform a material. It is given by the ratio of the shear stress to the shear strain.
Bulk modulus
A measure of how difficult it is to compress a substance. It is given by the ratio of the pressure on a body to the fractional decrease in volume.
Vapour pressure
A measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system.
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Specific heat capacity (J kg−1 K−1) |
479 | Young's modulus (GPa) | Unknown | |||||||||||
| Shear modulus (GPa) | Unknown | Bulk modulus (GPa) | 118 | |||||||||||
| Vapour pressure | ||||||||||||||
| Temperature (K) |
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| Pressure (Pa) |
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Podcasts
Podcasts
| Listen to Manganese Podcast |
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Transcript :
Chemistry in its element: manganese(Promo) You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry. (End promo) Chris Smith Hello! This week to the element that lies at the root of plant photosynthesis, fights free radicals, strengthens steel, makes mysterious ocean floor nodules and even goes to mix up with magnesium. Here's Ron Caspi. Ron Caspi I always feel that manganese is sadly overlooked. It's the fifth most abundant metal in the Earth crust and the second most abundant transition metal after iron, but say, manganese and many people will think of the much more familiar magnesium. There is a good reason why the names of these two elements are so confusingly similar, but we'll get to that in a minute. There are more than 300 different minerals that contain manganese. Large terrestrial deposits are found in Australia, Gabon, South Africa, Brazil and Russia. Yet more fascinating are the mysterious three trillion tons of manganese nodules that cover great parts of the ocean floor. These nodules are never covered by the constantly accumulating sediment. They manage to always stay above the sediment, due to the constant pushing and turning by their keepers, the small animals that live on the ocean floor. Almost half a billion dollars were invested in developing mining techniques for the nodules, but they're found so deep, mostly at depth of 4 to 6 kilometres, that the mining is still not commercially viable. Manganese is an extremely versatile element. It can exist in six different oxidation states. In nature, it is usually found in either its reduced +2 state, which easily dissolves in water or in the +4 state, which forms many types of insoluble oxides. The +3 form of manganese is used as a powerful weapon, by dry rot fungi that break down wood. Wood contains a lot of lignin, a polymer that is almost indestructible by biological systems; indestructible that is unless you use manganese. A fungal enzyme, manganese peroxidase, oxidizes manganese +2 atoms to manganese +3, which are then sent to the tiny spaces within the wood lattice. Manganese +3 is highly reactive and can break down the chemical bonds of lignin, making it available as food for the fungus. Fungi are not the only organisms that harness the power of manganese chemistry. Manganese is an essential element for all life forms. It is absolutely necessary for the activity of several enzymes that must bind a manganese atom before they can function, including superoxide dismutase, an enzyme that protects us from the harmful effects of toxic oxygen radicals. One of the most important reactions in biology, photosynthesis, is completely dependent on manganese. It is the star player in the reaction centre of photosystem II where water molecules are converted to oxygen. Without manganese, there would be no photosynthesis as we know it and there would be no oxygen in the atmosphere. While biology discovered manganese early on, it took humankind a bit longer. Already in ancient Egypt, glass blowers who got tired of their greenish glass founded by adding small amounts of certain minerals to the mix, they could make perfectly clear glass. They didn't realize it at that time, but these minerals, which were affectionately named, Sapo vitri or glass soap were manganese oxides. Excellent ores were found in the region of Magnesia, the region of northern Greece, just south of Macedonia, and this is how the trouble with manganese names started. Different ores from the region, which included both magnesium and manganese, were simply called magnesia. In the 1600s, the term magnesia alba or white magnesia was adopted for magnesium minerals, while magnesia nigra or black magnesia was used for the darker manganese oxides. By the way, the famous magnetic minerals that were discovered in that region were named Lapis magnis or stone of magnesia, which eventually became today's magnet. For a while, there was a total mix up concerning manganese and magnesium, but in the late 18th Century, a group of Swedish chemists, headed by Torbern Bergman were convinced that manganese is its own element. In 1774, Scheele, a member of the group presented these conclusions to the Stockholm Academy and later that year, Johann Gahn, another member became the first man to purify manganese and prove that it is an element. It took a few more years, but by 1807, the name manganese was accepted by all. Today, manganese is used for countless industrial purposes. By far, the most important one is in steel making. When Sir Henry Bessemer invented the process of steel making in 1856, his steel broke up when hot rolled or forged; the problem was solved later that year, when Robert Foster Mushet, another Englishman, discovered that adding small amounts of manganese to the molten iron solves the problem. Since manganese has a greater affinity for sulphur than does iron, it converts the low-melting iron sulphide in steel to high-melting manganese sulphide. Since then, all steel contains manganese. In fact, about 90% of all Manganese produced today, is used in steel. From the mysterious nodules at the bottom of the ocean to the decay of wood, from ancient glassblowing to modern steel-making, from fighting oxygen radicals to photosynthesis, manganese has always played a fascinating role in the chemistry, geology, and biology of our planet, a role that is seriously under appreciated. Chris Smith Ron Caspi. Next time, to a cheeky chemical with some practical and also some less than practical uses that is unless you're a practical joker. Andrea Sella Alloys containing bismuth were used for safety valves and boilers, melting if the temperature rose too high and a classic prank invented in Victorian times was to cast spoons from an alloy consisting of 8 parts bismuth, 5 parts lead and 3 parts tin. Its melting point is low enough for the spoon to vanish into a cup of hot tea to the astonishment of the unsuspected visitor. Chris Smith Andrea Sella, who'll be revealing the story of bismuth on next week's Chemistry in its element. I hope you can join us. I am Chris Smith, thank you for listening and goodbye! (Promo) Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists.com. There's more information and other episodes of Chemistry in its element on our website at chemistryworld.org/elements. (End promo)
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Resources
Resources
Terms & Conditions
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Data
W. M. Haynes, ed., CRC Handbook of Chemistry and Physics, CRC Press/Taylor and Francis, Boca Raton, FL, 95th Edition, Internet Version 2015, accessed December 2014.
Tables of Physical & Chemical Constants, Kaye & Laby Online, 16th edition, 1995. Version 1.0 (2005), accessed December 2014.
J. S. Coursey, D. J. Schwab, J. J. Tsai, and R. A. Dragoset, Atomic Weights and Isotopic Compositions (version 4.1), 2015, National Institute of Standards and Technology, Gaithersburg, MD, accessed November 2016.
T. L. Cottrell, The Strengths of Chemical Bonds, Butterworth, London, 1954.
Uses and properties
John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.
Thomas Jefferson National Accelerator Facility - Office of Science Education, It’s Elemental - The Periodic Table of Elements, accessed December 2014.
Periodic Table of Videos, accessed December 2014.
Supply risk data
Derived in part from material provided by the British Geological Survey © NERC.
History text
Elements 1-112, 114, 116 and 117 © John Emsley 2012. Elements 113, 115, 117 and 118 © Royal Society of Chemistry 2017.
Podcasts
Produced by The Naked Scientists.
Periodic Table of Videos
Created by video journalist Brady Haran working with chemists at The University of Nottingham.
