What is the origin of the color development of ionic solution?

Ask the comrades upstairs to explain why the pigment develops. And there is pigment in the sun? It's funny that it does involve physics, but it's not that simple, it involves the movement and transition of electrons, which is generally briefly introduced in basic inorganic chemistry.

I don't remember exactly, but I'll put it simply.

Since the electrons in atoms, ions or molecules are moving, when the energy meets certain conditions (such as after a certain wavelength of light) can make the electrons transition, and the electrons that jump to a higher energy level have a tendency to return to a lower energy level, so if the wavelength of the emitted light is within the visual range of the human eye, then we can see different colors due to the different wavelengths of the emitted light.

The above is the simplest principle of color development, and there are many more principles, which are more complex, but they also involve the transition of electron energy levels and the release of energy.

Because various ions have their different absorption wavelengths. For example, 2-valent copper has an absorption wavelength that is in the range of yellow light. In other words, all the yellow light is absorbed from the natural light of the solution, so that the complementary color of yellow light is released, blue light.

Everything else is in order.

In aqueous solutions, common colored ions are:

Cu2+ copper ions --- blue.

Fe2+ ferrous ions--- light green.

Fe3+ iron ions --- nearly colorless lilac (yellow is the color in general solutions.) ）

Mn2+ manganese ions--- light pink.

CO2 + cobalt ion --- pink.

Ni2+ nickel ions --- green.

Cr2+ chromium ions.

--Blue-green.

Cr3 + chromium ions.

--Green. CD2+ cadmium ions --- blue-green.

AU3+ gold ions--- golden yellow.

MNO4-permanganate ion.

--Amaranth.

mno42-

Manganate ions.

--Green.

CRO42-chromate ion.

--Yellow. CR2O72-dichromate ion.

--Orange. fe(scn)]2+

Ferric thiocyanide complex ions --- blood-red.

cucl4]2-

Copper tetrachloride complex ions --- yellow.

Blood Red: The color of Fe3+ when it encounters SCN-.

Summary. Yes, colored ions develop color in solutions with a large number of impurities because these colored ions react with impurities to produce different wavelength spectra and thus display different colors.

Yes, colored ions will develop color in solutions with a large number of impurities, because these imitation colored ions will react with impurities to produce different wave backup growth spectrum, thus showing different colors.

Will diluting this solution make the color more pronounced?

Diluting the solution may make color development more pronounced because the impurity concentration is reduced and the absorption spectrum of colored ions is more pronounced. But the dross is, it depends on the specific macro cavity of the solution, such as the type and concentration of impurities.

So if such a solution contains very little water, is the color obvious?

If the amount of buried moisture in this solution is very small, the color display may be affected and will not be very noticeable. Therefore, the color development of colored ions is affected by various factors such as the composition, concentration and solvent of the solution.

Blue: Copper ions. Brownish-yellow: ferric ions. Light green: ferrous ions. Blood-red: ferric thiocyanide trivalent celery (ferric ferric). Purple: permanganate ions.

In aqueous solutions, some ions are colored.

Common colored ions are:

Cu2+ copper ions --- blue.

Fe2+ ferrous ions--- light green.

Fe3+ iron ion -- light purple (generally brownish-yellow in solution).

Mn2+ manganese ions--- light pink.

CO2 + cobalt ion --- pink.

Ni2+ nickel ions --- green.

Cr2 + chromium ion - blue-green.

Cr3 + chromium ion - green.

CD2+ cadmium ions --- blue-green.

AU3+ gold ions--- golden yellow.

Blue: Copper ions. Brownish-yellow: ferric ions. Light green: ferrous ions. Blood-red: ferric thiocyanide trivalent celery (ferric ferric). Purple: permanganate ions.

In aqueous solutions, some ions are colored.

Common colored ions are:

Cu2+ copper ions --- blue.

Fe2+ ferrous ions--- light green.

Fe3+ iron ion -- light purple (generally brownish-yellow in solution).

Mn2+ manganese ions--- light pink.

CO2 + cobalt ion --- pink.

Ni2+ nickel ions --- green.

Cr2 + chromium ion - blue-green.

Cr3 + chromium ion - green.

CD2+ cadmium ions --- blue-green.

AU3+ gold ions--- golden yellow.

Blue: Copper ions. Brown and yellow jujube color:

Trivalent iron is cautious. Light green: ferrous ions.

Blood red: ferric thiocyanide from verry (ferric iron). Purple:

Permanganate ions. In aqueous solutions, some ions are colored. Common colored ions are:

Cu2+ copper ions --- blue. Fe2+ ferrous ions--- light green. Fe3+ iron ions--- light purple (Xiangxiao in solution is generally brownish-yellow).

Mn2+ manganese ions--- light pink. CO2 + cobalt ion --- pink. Ni2+ nickel ions --- green.

Cr2 + chromium ion - blue-green. Cr3 + chromium ion - green. CD2+ cadmium ions --- blue-green.

AU3+ gold ions--- golden yellow. Expansion Balance Exhibition Information: Colored ferrous ions:

Material characteristics: The chemical valence of a substance called sub in chemistry must be lower than its highest chemical valence, but it is not necessarily the chemical valence in the middle (for example, the chemical valence of chlorine is -10 + 1 + 3 + 5 + 7 valence is the highest chemical valence of the liquid.

Whether an ion can develop color is related to whether it can absorb visible light, and whether it can absorb visible light depends on the electronic shell structure of the ion. If the electron sublayers outside the nucleus are in a full state, that is, when there are no unpaired electrons, the structure is relatively stable, it is not easy to accept the excitation of light energy, it is not easy to absorb visible light, and it is colorless. The electro-layer structure of the transition metal ions mentioned above is less stable and generally contains an unfilled D sublayer with an unequal number of unpaired electrons.

These unstable electrons are susceptible to light excitation and undergo a transition, that is, the absorption and reflection of certain wavelengths of visible light, showing different colors.

For example, Mn2+ in solution is light pink, but Mn(OH)2 is white, and FeO and FeS are black. Generally speaking, the larger the radius of the negative ion, the more relaxed the peripheral electrons, and the darker the color of the compound or atomic cluster formed.

In addition to negative ions that can affect the color development of transition metal ions, water molecules also have a certain effect. The crystal or solution of copper sulfate appears beautiful blue, but when we put the blue copper sulfate crystal in the test tube and heat, the beautiful blue color will gradually disappear, and at the same time, the resulting water vapor will become liquid when it is cold, and then drip from the mouth of the test tube, like tears shed for the loss of beautiful color. At this point, all that is left in the tube is white powder.

Not only does the presence of water molecules affect the display of color, but the number of water molecules also plays a significant role. For example, cobalt chloride crystals, at room temperature, are pink; When heated to more than 52 and lost water, it becomes purple-red CoCl2·2H2O. Continue to heat to 90 to turn blue-purple CoCl2·H2O, and then reheat will lose all water and become blue CoCl2.

1.Typical ionic compounds generally do not absorb light in the visible region of the spectrum (generally ultraviolet light) and therefore appear white or colorless when exposed to white light.

2.When the chemical bonds between metal and non-metal atoms become more covalent, the electron density gradually shifts from anion to cation, and the charge transition is easier, and less energy is required. The absorbable band is shifted to the visible region.

At this time, the white light that was originally completely emitted is partially absorbed, and the reflected or transmitted light emitted at this time will be colored.

3.The depth of color rendering can determine the covalentity of the chemical bonds of metal atoms (excessive elements) with non-metal atoms... This is what the old man said about the electronic sublayer (spdfg......).

In essence, this is caused by the transition of electrons, according to the classical Maxwell's theory, electrons will be at a higher energy level after getting energy, from the principle of lowest energy, it can be seen that the electrons after absorbing energy are unstable and then transition, so as to reach a stable low-energy orbit, and the energy will be released in the form of electromagnetic waves, different particles absorb different energy, so after the transition, electromagnetic waves of different wavelengths are emitted, one of which is in the visible region, so it is what we call the flame color reaction.

A substance with a green color.

Light green: Cu2(OH)2CO3, FeCl2, FeSO4 7H2O.

Green: The color of the concentrated CuCl2 solution and pH test paper at about pH=8.

Dark black-green: K2MNO4.

Yellow-green: extracts of Cl2 and its Ccl4.

NO2 - light yellow.

Cu2+ or [Cu(H2O)4]2+

Blue. mno4-

Purple. cucl4]2-

Yellow. mno42-

Green. cu（nh3）4]2+

Blue. cr2o72-

Orange-red. fe2+

Aqua. CRO42-Yellow.