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  2. Hume-Rothery rules - Wikipedia

    en.wikipedia.org/wiki/Hume-Rothery_rules

    [5] [6] The solute and solvent should have similar electronegativity. [7] Valency factor: two elements should have the same valence. The greater the difference in valence between solute and solvent atoms, the lower the solubility.

  3. Valence (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Valence_(chemistry)

    Thus, each sulfur atom is hexavalent or has valence 6, but has oxidation state +5. In the dioxygen molecule O 2, each oxygen atom has 2 valence bonds and so is divalent (valence 2), but has oxidation state 0. In acetylene H−C≡C−H, each carbon atom has 4 valence bonds (1 single bond with hydrogen atom and a triple bond with the other ...

  4. Pauling's rules - Wikipedia

    en.wikipedia.org/wiki/Pauling's_rules

    One of Pauling's examples is olivine, M 2 SiO 4, where M is a mixture of Mg 2+ at some sites and Fe 2+ at others. The structure contains distinct SiO 4 tetrahedra which do not share any oxygens (at corners, edges or faces) with each other. The lower-valence Mg 2+ and Fe 2+ cations are surrounded by polyhedra which do share oxygens.

  5. Sulfur cycle - Wikipedia

    en.wikipedia.org/wiki/Sulfur_cycle

    Sulfur can be found under several oxidation states in nature, mainly −2, −1, 0, +2 (apparent), +2.5 (apparent), +4, and +6. When two sulfur atoms are present in the same polyatomic oxyanion in an asymmetrical situation, i.e, each bound to different groups as in thiosulfate, the oxidation state calculated from the known oxidation state of accompanying atoms (H = +1, and O = −2) can be an ...

  6. Hydrogen sulfide - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_sulfide

    Hydrogen sulfide is a highly toxic and flammable gas (flammable range: 4.3–46%). It can poison several systems in the body, although the nervous system is most affected. [citation needed] The toxicity of H 2 S is comparable with that of carbon monoxide. [55] It binds with iron in the mitochondrial cytochrome enzymes, thus preventing cellular ...

  7. Sulfamic acid - Wikipedia

    en.wikipedia.org/wiki/Sulfamic_acid

    Sulfamic acid (H 3 NSO 3) may be considered an intermediate compound between sulfuric acid (H 2 SO 4), and sulfamide (H 4 N 2 SO 2), effectively replacing a hydroxyl (–OH) group with an amine (–NH 2) group at each step. This pattern can extend no further in either direction without breaking down the sulfonyl (–SO 2 –) moiety.

  8. Selenate - Wikipedia

    en.wikipedia.org/wiki/Selenate

    The element selenium exhibits several valence states. Selenate is the least reduced, followed by selenite, and elemental selenium; selenide is even more reduced than elemental selenium. [6] The valence state is an important factor to the toxicity of selenium. Selenate is the form required by organisms that need selenium as a micronutrient.

  9. Electronic properties of graphene - Wikipedia

    en.wikipedia.org/wiki/Electronic_properties_of...

    Graphenem, a single layer of carbon atoms, exhibits an unusual form of the quantum Hall effect. In graphene, the steps of conductivity quantization are shifted by 1/2 compared to the standard sequence and have an additional factor of 4. This can be expressed as: = (+ /) /