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  2. Group 7 element - Wikipedia

    en.wikipedia.org/wiki/Group_7_element

    All group 7 elements crystallize in the hexagonal close packed (hcp) structure except manganese, which crystallizes in the body centered cubic (bcc) structure. Bohrium is also expected to crystallize in the hcp structure. [1] The table below is a summary of the key physical properties of the group 7 elements. The question-marked value is ...

  3. Hydrogen ion - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_ion

    The concentration of hydrogen ions and pH are inversely proportional; in an aqueous solution, an increased concentration of hydrogen ions yields a low pH, and subsequently, an acidic product. By definition, an acid is an ion or molecule that can donate a proton, and when introduced to a solution it will react with water molecules (H 2 O) to ...

  4. Periodic table (crystal structure) - Wikipedia

    en.wikipedia.org/wiki/Periodic_table_(crystal...

    This structure can also be considered to be a distorted hcp lattice with the nearest neighbours in the same plane being approx 16% farther away [18] β-Po: A i: Rhombohedral: R 3 m (No. 166) 1 (rh.) 3 (hex.) Identical symmetry to the α-Hg structure, distinguished based on details about the basis vectors of its unit cell. γ-Se: A8: Hexagonal ...

  5. Hydron (chemistry) - Wikipedia

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

    In chemistry, the hydron, informally called proton, [2] is the cationic form of atomic hydrogen, represented with the symbol H +The general term "hydron", endorsed by IUPAC, encompasses cations of hydrogen regardless of isotope: thus it refers collectively to protons (1 H +) for the protium isotope, deuterons (2 H + or D +) for the deuterium isotope, and tritons (3 H + or T +) for the tritium ...

  6. Lanthanide compounds - Wikipedia

    en.wikipedia.org/wiki/Lanthanide_compounds

    Lanthanide metals react exothermically with hydrogen to form LnH 2, dihydrides. [1] With the exception of Eu and Yb, which resemble the Ba and Ca hydrides (non-conducting, transparent salt-like compounds),they form black pyrophoric, conducting compounds [6] where the metal sub-lattice is face centred cubic and the H atoms occupy tetrahedral sites. [1]

  7. Dihydrogen cation - Wikipedia

    en.wikipedia.org/wiki/Dihydrogen_cation

    The dihydrogen cation or hydrogen molecular ion is a cation (positive ion) with formula +. It consists of two hydrogen nuclei , each sharing a single electron. It is the simplest molecular ion. The ion can be formed from the ionization of a neutral hydrogen molecule by

  8. Coordination geometry - Wikipedia

    en.wikipedia.org/wiki/Coordination_geometry

    In a crystal structure the coordination geometry of an atom is the geometrical pattern of coordinating atoms where the definition of coordinating atoms depends on the bonding model used. [1] For example, in the rock salt ionic structure each sodium atom has six near neighbour chloride ions in an octahedral geometry and each chloride has ...

  9. Trihydrogen cation - Wikipedia

    en.wikipedia.org/wiki/Trihydrogen_cation

    The structure of H + 3 The MO diagram of the trihydrogen cation. The three hydrogen atoms in the molecule form an equilateral triangle , with a bond length of 0.90 Å on each side. The bonding among the atoms is a three-center two-electron bond , a delocalized resonance hybrid type of structure.