Unstable structures are common in organic chemistry

There are two main types of exposure at the secondary school level: one is the enol formula, that is, the hydroxyl group is directly attached to the unsaturated carbon (except the carbon on the benzene ring), which will be converted into ketones (aldehydes) with isomerization. In the second type, two hydroxyl groups are attached to the same carbon, and the two hydroxyl groups will fight, and when they hit the water, they will become ketones (aldehydes).

At the university level, there are many unstable structures, but there are ways to tell if a structure is stable.

In addition, the concept of "unstable structure" is too vague.

It is mainly based on the chemical bonds, to see if there is an electronic shift on both sides of the bond. Due to the different redox properties of different atoms, when combined into a bond, it will inevitably cause electrons to move to the side with strong oxidation, so from this bond alone, the greater the offset, the more unstable the bond. However, if you look at the whole molecule, it is possible that each bond has the same degree of offset, and it is possible that the whole molecule becomes stable.

For example, silicon carbide, the carbon-silicon bond is not "stable", the electrons are biased towards carbon, but the whole molecule is relatively stable, because the bonds in the molecule are arranged in a consistent order.

There is also an unstable structure between molecules, although it is not necessarily a bond, but it may be that one atom is too oxidizing and robs the electrons in other molecules, so it itself will be unstable. The same is true for the fact that the reductivity is so high that it loses electrons.

1. Enol type.

2. There are two -oh on c

3. C+ or C-ion.

4. There is a halogen and a -OH on C

5. Diazonium salt.

etc. cannot exist stably.

Three, quaternied rings.

It is a carboxylic acid with an electron-withdrawing group on it.

Hydroxyaldehydes and ketones (products in aldol condensation, aliphatic aldehydes and ketones can stay at this step) can exist stably, but the activity is high and it is easy to react (ring opening, decarboxylation, dehydration).

Two hydroxyl groups attached to a carbon group are unstable and automatically dehydrate a part of water.

The hydroxyl group and the double bond are unstable on a carbon, as if they are turning into aldehydes.

Two double bonds connected to a carbon are unstable and automatically become single and triple bonds.

Resonance and free radicals are all unstable.

Resonance radicals.

You can't have two double bonds attached to a carbon at the same time.

Stable structure refers to the number of electrons in the outermost shell of an atom reaching (hydrogen is up to 2).

For example, the outermost electron of the sodium atom is 1, and when it loses one electron, the outermost electron reaches 8, so the sodium ion is more stable than the sodium atom; For example, the outermost electron number of the chlorine atom is 7, and when it gets one electron, it becomes 8, so the chloride ion is more stable than the chlorine atom.

The number of outermost electrons is less than (or equal to) 3, such as alkali metal and alkaline earth metal elements, it is easy to lose the outermost electrons and reach the stable structure of the outermost 8 electrons, which makes it very metallic and reducible. However, this does not apply to subgroup elements, such as gold and silver, which have 1 electron in the outermost shell, and mercury in the outermost shell which has 2 electrons, but they are both inactive.

A stable structure is a structure in which the number of electrons in the outermost shell of an atom is 8 (the first shell is the outermost shell is 2), and it is a stable structure. If the original atom gains and loses electrons, the outermost shell becomes a structure of 8 electrons, which is a relatively stable structure, because the atom is likely to lose or regain the electrons it has gained or lost.

Generally speaking, a structure with an outermost electron count of 8 electrons is neither easy to gain or lose electrons, but also relatively stable in chemical properties, and is called a relatively stable structure.

For a particle with only one electron shell, with 2 electrons, it has a relatively stable structure.

That is, the outermost electrons of an atom are less than 4 and lose electrons, and those greater than 4 gain electrons until the outermost electrons reach 8, so that a relatively stable structure is formed, my understanding is so, I hope it can help you.

It is not easy to gain and lose electrons, for example, there are 8 electrons in the outermost shell, and a stable structure is reached.

1) Stability --- are relative!

2) In addition to the unstable and perishable ones, Ming Weixiao is a stable radical compound.

3) Unstable compounds are:

feso4,,(nh4)2fe(so4),2snci2,h2s(aq),na2so3,hcio,hno3...

Because there are many kinds of organic cracks. Reasons for the wide variety of organic traces:

1. The carbon atom has 4 valence electrons and can form 4 pairs of shared electron pairs with other atoms;

2. Carbon, carbon atoms can be combined into chains, or into rings;

3. Carbon can be combined with single, double or triple bonds between carbon atoms;

4. The number of carbon atoms can be different, and molecules containing the same atomic type and number may have different structures.

If we consider that most organic substances can be regarded as derivatives of hydrocarbons, and hydrocarbons are non-polar molecules, and non-polar molecules are relatively stable, so there are more sufficient conditions to produce derivatives.

It is because the hydrocarbons are relatively stable, and the stability will produce accumulation, and the amount is sufficient to produce complex derivatives under the random conditions of the state.

1. For naphthenes, each hydrogen atom is configured in a chair shape.

The repulsion is the most stable, so options B, C, and D are more stable than A;

2. A vertical axis of symmetry can be drawn in the middle of the ring structure.

The direction of each carbon atom parallel to the axis of symmetry is called a bond, and the one that is angled to the axis of symmetry is called an bond, taking b as an example, the cl bond is called a bond, and the c(ch3)3 bond is called an e-bond. The A-bond hydrogen atoms are closer together and have a greater repulsion force, which is less stable compared to the E-bond. If there are multiple substituents on the ring, it is often the E-bond substituents.

for stable conformation; If there are different substituents on the ring, the larger group is the stable conformation on the E bond.

Therefore, b is more stable than c, and d is the most stable in general.

Stable structure: The general steady state is the outermost orbital electron full full, that is, eight electrons, hydrogen is two electrons or semi-filled, and the third main group elements are more stable. If the compound element satisfies eight electrons, it is stable, such as carbon dioxide, and if it is nitrogen dioxide, it is unstable and active, because nitrogen is positive, tetravalent, and does not satisfy eight electrons.

Reaction stability: Generally refers to the difficulty of chemical substances to change in the real state, with good stability and not easy to change. The so-called state of reality is also the environment in which we live.

Most of these changes are chemical changes, such as: reaction with oxygen, natural decomposition, reaction with moisture in the air, etc.; There are also physical changes, such as: volatilization, precipitation, concentration, etc.

Khan ......That's a lot.

Can you just fill in the blanks......

Unstable. For example, ......

Poisonous. cn2

Cl2 is strongly corrosive.

Concentrated sulfuric acid. Concentrated nitric acid.

Anyway, the strong alkali and strong acid are all ......

Dehydration. Concentrated sulfuric acid.

Acidic ......Hydrochloric acid, sulfuric acid, nitric acid......Let Zheng be very slippery and respectful.

Alkaline. Sodium hydroxide, potassium, calcium ......

Neuter. Water.

Sodium chloride solution ......

The upstairs is not complete, Zi Sou and I will make up for what he didn't tell Lu to answer.

Common unstable substances are (NaHCO3, H2CO3, HCOs, NOs, etc.).

I wish the landlord a happy chemistry socks!

Carbon and carbon monoxide are relatively stable at room temperature, so they are correctly slippery;

Both carbon and carbon monoxide can be burned in the air, so it is correct;

Both carbon and carbon monoxide need to react with copper oxide under heated conditions; Therefore it is wrong;

Carbon transport wax resistance transport and carbon monoxide react with metal oxides to obtain oxygen, which is a reducing agent, with reducing properties, so it is correct;

Carbon and carbon monoxide are reducible in the reaction, so they are wrong;

Therefore, C

Hello, the c=c and hydroxyl groups you said do not belong to unstable structures, they are functional groups, and they can have some specific reactions of the functional group, in fact, they are stable before encountering the substances that react with the functional group.

The so-called unstable structure generally refers to the fact that it is difficult to exist on its own. For example, two hydroxyl groups attached to a carbon group are unstable, and a part of water is automatically removed. The hydroxyl group and the double bond are unstable on a carbon, as if they are turning into aldehydes.

Functional groups are atoms or groups of atoms that determine the chemical properties of organic compounds. Common functional groups such as olefins, alcohols, phenols, ethers, aldehydes, ketones, etc. Organic chemical reactions mainly occur on functional groups, which play a decisive role in the properties of organic matter, -X, -OH, -CHO, -COOH, -NO2, -SO3H, -NH2, RCO-, these functional groups determine the chemical properties of halogenated hydrocarbons, alcohols or phenols, aldehydes, carboxylic acids, nitro compounds or nitrites, sulfonic acid organic compounds, amines, and amides in organic matter.

It so happened that we were standing on the same single-plank bridge, and I also thought that br2 was very troublesome, and I started with olefins, and olefins and alkynes are actually essentially additions to br2 ch2 = ch2 + br2- ch2brch2br (dibromoethane) acetylene and br2 (dibromoethylene) in the formation of tetrabromoethane) conditions do not require a catalyst benzene is not bromine water fade but fade the bromine water layer is extraction benzene reacts with liquid bromine when fe is used as a catalyst to form bromine benzene (a colorless oily liquid with a density heavier than water) The equation is not played, hehe, it is too troublesome to remove the bromine in the bromine with NaOH solution Pay attention to the dropwise addition sequence of the reagent and the condensation reflux device of the experimental device The homologues of benzene will not fade the bromine water and fade the bromine water layer Here we must distinguish that the homologues of benzene react with bromine water under light to replace the hydrogen atom on the hydrocarbon group, and when the iron is used as a catalyst, it is substituted on the ben ring Phenol reacts with concentrated bromine water to form tribromophenol (white precipitate), which can be used to identify phenol, but the amount of phenol should be less to prevent tribromophenol from being tolerant of phenol The phenomenon is not clear It should also be noted The position of bromine substitution Ortho alignment This point is often examined Summary of organic matter that can discolor bromine water 1 Addition reaction with unsaturated hydrocarbons such as olefins and alkynes to discolor bromine water 2 Redox reaction with reducing substances (including aldehydes) is bromine water discoloration 2 Substitution with phenol should fade bromine water I know about these I hope it can help you I wish you good results in the college entrance examination.

Even two hydroxyl groups or two double bonds on a carbon are unstable.