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Iodine, the rarest of the nonmetallic halogens, is a metallic looking solid that is moderately reactive, and has a density of 4.933 g/cm 3. It melts at 113.7 °C to a brown liquid and boils at 184.3 °C to a violet-coloured vapour.
This is an accepted version of this page This is the latest accepted revision, reviewed on 31 December 2024. This article is about the chemical element. For other uses, see Iodine (disambiguation). Chemical element with atomic number 53 (I) Iodine, 53 I Iodine Pronunciation / ˈ aɪ ə d aɪ n, - d ɪ n, - d iː n / (EYE -ə-dyne, -din, -deen) Appearance lustrous metallic gray solid ...
Iodine crystals, showing a metallic lustre. Iodine is a semiconductor in the direction of its planes, with a band gap of ~1.3 eV. It has an electrical conductivity of 1.7 × 10 −8 S•cm −1 at room temperature. [489] This is higher than selenium but lower than boron, the least electrically conducting of the recognised metalloids. [n 51]
The metallic luster of the minerals of the group resembles the luster of the surface of a fresh fracture of metals. It is clearly visible only on the non-oxidized surface of the sample. Minerals that have a metallic luster are, as a result, opaque and heavier than minerals that have a non-metallic luster.
Iodine trichloride, which exists in the solid state as the planar dimer I 2 Cl 6, is a bright yellow solid, synthesised by reacting iodine with liquid chlorine at −80 °C; caution is necessary during purification because it easily dissociates to iodine monochloride and chlorine and hence can act as a strong chlorinating agent.
The halogens (/ ˈ h æ l ə dʒ ə n, ˈ h eɪ-,-l oʊ-,-ˌ dʒ ɛ n / [1] [2] [3]) are a group in the periodic table consisting of six chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and the radioactive elements astatine (At) and tennessine (Ts), though some authors [4] would exclude tennessine as its chemistry is unknown and is theoretically expected to ...
These iodine compounds are hypervalent because the iodine atom formally contains in its valence shell more than the 8 electrons required for the octet rule. Hypervalent iodine oxyanions are known for oxidation states +1, +3, +5, and +7; organic analogues of these moieties are known for each oxidation state except +7.
Structures within a surface cause light to be reflected back, but in the case of pearlescence some or most of the light is white, giving the object a pearl-like luster. [16] Artificial pigments and paints showing an iridescent effect are often described as pearlescent, for example when used for car paints .