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  2. Manganese - Wikipedia

    en.wikipedia.org/wiki/Manganese

    The oxygen-evolving complex (OEC), containing four atoms of manganese, is a part of photosystem II contained in the thylakoid membranes of chloroplasts. The OEC is responsible for the terminal photooxidation of water during the light reactions of photosynthesis , i.e., it is the catalyst that makes the O 2 produced by plants.

  3. Carbon group - Wikipedia

    en.wikipedia.org/wiki/Carbon_group

    A fifth allotrope of carbon, discovered in 2003, is called graphene, and is in the form of a layer of carbon atoms arranged in a honeycomb-shaped formation. [6] [14] [15] Silicon has two known allotropes that exist at room temperature. These allotropes are known as the amorphous and the crystalline allotropes. The amorphous allotrope is a brown ...

  4. Group 7 element - Wikipedia

    en.wikipedia.org/wiki/Group_7_element

    An abundant resource of manganese in the form of Mn nodules found on the ocean floor. [85] [86] These nodules, which are composed of 29% manganese, [87] are located along the ocean floor and the potential impact of mining these nodules is being researched. Physical, chemical, and biological environmental impacts can occur due to this nodule ...

  5. Allotropy - Wikipedia

    en.wikipedia.org/wiki/Allotropy

    Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in crystalline structure.. Allotropy or allotropism (from Ancient Greek ἄλλος (allos) 'other' and τρόπος (tropos) 'manner, form') is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of the elements.

  6. Properties of metals, metalloids and nonmetals - Wikipedia

    en.wikipedia.org/wiki/Properties_of_metals...

    Manganese has a complex crystal structure with a 58-atom unit cell, effectively four different atomic radii, and four different coordination numbers (10, 11, 12 and 16). It has been described as resembling "a quaternary intermetallic compound with four Mn atom types bonding as if they were different elements."

  7. Inorganic compound - Wikipedia

    en.wikipedia.org/wiki/Inorganic_compound

    All allotropes (structurally different pure forms of an element) and some simple carbon compounds are often considered inorganic. Examples include the allotropes of carbon ( graphite , diamond , buckminsterfullerene , graphene , etc.), carbon monoxide CO , carbon dioxide CO 2 , carbides , and salts of inorganic anions such as carbonates ...

  8. Period 3 element - Wikipedia

    en.wikipedia.org/wiki/Period_3_element

    A period 3 element is one of the chemical elements in the third row (or period) of the periodic table of the chemical elements.The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behavior of the elements as their atomic number increases: a new row is begun when chemical behavior begins to repeat, meaning that elements with similar behavior fall into ...

  9. Law of multiple proportions - Wikipedia

    en.wikipedia.org/wiki/Law_of_multiple_proportions

    In reality, an ethylene molecule has two carbon atoms and four hydrogen atoms (C 2 H 4), and a methane molecule has one carbon atom and four hydrogen atoms (CH 4). In this particular case, Dalton was mistaken about the formulas of these compounds, and it wasn't his only mistake. But in other cases, he got their formulas right.