Химикаттардың түсі және олардың физикалық қасиеттері

Physical property of chemicals
The color of chemicals is a physical property of chemicals that in most cases comes from the excitation of electrons due to an absorption of energy performed by the chemical. What is seen by the eye is not the color absorbed, but the complementary color from the removal of the absorbed wavelengths. This spectral perspective was first noted in atomic spectroscopy. The study of chemical structure by means of energy absorption and release is generally referred to as spectroscopy.

The vast majority of simple inorganic (e. g. sodium chloride) and organic compounds (e. g. ethanol) are colorless. Transition metal compounds are often colored because of transitions of electrons between d orbitals of different energy. (see Transition metal#Colored compounds). Organic compounds tend to be colored when there is extensive conjugation, causing the energy gap between the HOMO and LUMO to decrease, bringing the absorption band from the UV to the visible region. Similarly, color is due to the energy absorbed by the compound, when an electron transitions from the HOMO to the LUMO. Lycopene is a classic example of a compound with extensive conjugation (11 conjugated double bonds), giving rise to an intense red color (lycopene is responsible for the color of tomatoes). Charge transfer complexes tend to have very intense colors for different reasons.

+Colors of metallic ions Name Formula Color Alkaline earth metals Mg2+ Colorless Scandium(III) Sc3+   Silver Titanium(III) Ti3+   Purple Titanium(IV) Ti4+   Silver Titanyl TiO2+ Colorless Vanadium(II) V2+   Light purple Vanadium(III) V3+   Dark grey green Vanadyl(IV) VO2+   Blue Vanadium(IV) (vanadite)   Brown Vanadium(V) (pervanadyl) VO2+   Yellow Metavanadate VO3− Colorless Orthovanadate VO43− Colorless Chromium(II) Cr2+   Bright blue Chromium(III) Cr3+   Blue green grey Chromium(III) hydroxide Cr(OH)63−   yellowish Monochromate CrO42−   Yellow Dichromate   Orange Manganese(II) Mn2+   Pale pinkManganese(III) Mn3+   Crimson Manganate(V) MnO43−   Deep blue Manganate(VI) MnO42−   Dark greenManganate(VII) (permanganate) MnO4−   Deep purple Iron(II) Fe2+   Greenish Cobalt(II) fluoride Co2+   Pink Cobalt(III) amine   Yellow/orange Nickel(II) Ni2+   Light green Nickel(II) amine complex   Lavender/blue Copper(I) amine complex Colorless Copper(II) Cu2+   Blue Copper(II) amine complex   Indigo blue Copper(II) chloride CuCl42− Blue Green Zinc(II) Zn2+ Colorless Silver(I) Ag+ Colorless Silver(III) in conc. HNO3 Ag3+   Dark brown
It is important to note, however, that elemental colors will vary depending on what they are complexed with, often as well as their chemical state. An example with vanadium(III); VCl3 has a distinctive reddish hue, whilst V2O3 appears black.