anion

Negatively charged ion

Collection

zero Useful+1

zero

synonym anion (Negative ion) generally refers to anion

This entry is made by China Science and Technology Information Magazine Participate in editing and review Science Popularization China · Science Encyclopedia authentication.

Anion refers to an ion whose atom obtains one or several electrons due to external action, so that the number of its outermost electrons reaches a stable structure. Anions are negatively charged ions. The number of nuclear charges=the number of protons<the number of extranuclear electrons. The number of negative charges carried is equal to the number of electrons obtained by atoms.

Chinese name: anion
Foreign name: anion

Charged property: negative
Symbol: “－”
Principle: Atoms get electrons due to external actions

catalog

definition

Announce

edit

The charged particles formed after atoms lose or gain electrons are called ions, such as sodium ion Na + 。 The charged atomic group is also called "ion", such as sulfate ion. Some molecules can also form ions under special circumstances.^[1]

Ions with one or more negative charges are called "anions". Many anions are stable structures in which atoms attract one or more electrons from the outside due to their own attraction, so that the number of the outermost electrons reaches 8 or 2. The smaller the radius of an atom, the stronger its ability to absorb electrons, the easier it is to form anions, and the stronger its non-metallic properties. The electrons with more than 4 electrons in the outermost layer of the atom are easy to form anions (non-metallic substances have negative valence, and anions are represented by the symbol "-"). Common anions are chloride ion Cl - , sulfur ion S 2- , hydroxyl OH - Etc.

Simple anion

Announce

edit

name	chemical formula	combined term
Arsenic ion	As 3−	Arsenide
Azide ion	N3 −	Azide
Bromine ion	Br −	Bromide
Chloride ion	Cl −	chloride
Fluoride ion	F −	fluoride
Hydrogen anion	H −	hydride
Iodine ion	I −	Iodide
Nitrogen ion	N 3−	nitrides
Oxyion	O 2−	oxide
Phosphorus ion	P 3−	Phosphide
Sulfur ion	S 2−	sulfide
Peroxide ion	O two 2−	peroxide

Oxyacid radical

Announce

edit

name	chemical formula	combined term
Arsenate ion	AsO four 3−	Arsenate
Arsenite ion	AsO three 3−	Arsenite
Borate ion	BO three 3−	borate
Bromate ion	BrO three −	Bromate
Hypobromate ion	BrO −	Hypobromate
carbonate ion	CO three 2−	carbonate
Bicarbonate ion	HCO three −	Bicarbonate
Hydroxyl ion	OH −	hydroxide
Chlorate ion	ClO three −	Chlorate
Perchlorate ion	ClO four −	Perchlorate
Chlorite ion	ClO two −	Chlorite
Hypochlorite ion	ClO −	Hypochlorite
Chromate ion	CrO four 2−	chromate
Dichromate ion	Cr two O seven 2−	Dichromate
iodate ion	IO three −	Iodate
Nitrate ion	NO three −	Nitrate
Nitrite ion	NO two −	nitrite
Phosphate ion	PO four 3−	phosphate
Phosphite ion	HPO three 2−	Phosphite
Monohydrogen phosphate ion	HPO four 2−	Monohydrogen phosphate
Dihydrogen phosphate ion	H two PO four −	Dihydrogen phosphate
Manganate ion	MnO four 2−	Manganate
Permanganate ion	MnO four −	permanganate
Sulfate ion	SO four 2−	sulfate
Thiosulfate ion	S two O three 2−	Thiosulfate
Bisulfate ion	HSO four −	Bisulfate
Sulfite ion	SO three 2−	Sulfite
Bisulfite ion	HSO three −	Bisulfite
Persulfate ion	S two O eight 2−	Persulfate
Silicate ion	SiO four 4−	silicate
Metasilicate ion	SiO three 2−	Metasilicate
Aluminosilicate ion	AlSiO four −	Aluminosilicate

Organic acid radical ion

Announce

edit

name	chemical formula	combined term
Acetate ion	C two H three O two −	Acetate
Formate ion	HCO two −	Formate
Oxalate ion	C two O four 2−	oxalate
Oxalate hydrogen ion	HC two O four −	Oxalate

Other anions

Announce

edit

name	chemical formula	combined term
Hydrogen sulfide ion	HS −	Hydrogen sulfide
Tellurium ion	Te 2−	Telluride
Amino anion	NH two −	Amino salt
Cyanate ion	OCN −	Cyanate
Thiocyanate ion	SCN −	Thiocyanate
Cyanogen ion	CN −	cyanide

Common color of ions

Announce

edit

name	chemical formula	colour
Permanganate ion	MnO four -	violet
Manganate ion	MnO four 2-	green
Chromate ion	CrO four 2-	yellow
Dichromate ion	Cr two O seven 2-	orange
Bromine ion	Br -	canary yellow

Anion experiment

Announce

edit

Experiment purpose

Be familiar with the properties of common anions

Master the separation methods of common anions

Experimental principle

There are 13 common anions as follows: SO four 2- 、SiO three 2- 、PO four 3- 、CO three 2- 、SO three 2- 、S two O three 2- 、S 2- 、Cl - 、Br - 、I - 、NO 3- 、NO two - 、Ac -

In anions, some are easy to decompose in case of acid, and some can not coexist with each other due to oxidation and reduction. Therefore, anion analysis has the following two characteristics:

Anions are easy to change in the analysis process, and it is not easy to carry out systematic analysis with various procedures.

There are few opportunities for anions to coexist with each other, and there are many specific reactions available, which may require separate analysis.

In the analysis of anions, separate analysis method is mainly used. Only when some anions interfere with each other during identification, separation method can be properly adopted. However, the separate analysis method is not to test all the studied ions one by one, but to eliminate the anions that certainly do not exist through preliminary experiments, and then to determine the possible anions one by one.

Preliminary experiment

1 Sedimentation test

(1) And BaCl two Reaction of

Drop SO into 13 centrifuge tubes respectively four 2- 、SiO three 2- 、 PO four 3- 、SO three 2- 、 CO three 2- 、 S two O three 2- 、S 2- 、Cl - 、Br - 、I - 、NO three - , NO2 -, Ac -, two drops each, and then one drop of 0.5M BaCl2.

Reaction equation:

1) Ba 2+ + SO four 2- =BaSO4 ↓ (white)

2) Ba 2+ + SiO three 2- =BaSiO3 ↓ (white)

BaSiO three +2HCl=H two SiO three ↓ (colloidal)+BaCl two

3) 3 Ba 2+ +2 PO four 3- =Ba 3( PO four ) two ↓ (white)

Ba three (PO four ) two +3 HCl= BaCl two +H three PO four

4) Ba 2+ + CO three 2- =BaCO three ↓ (white)

BaCO three +2 HCl= BaCl two +H two O+CO two ↑

5) Ba 2+ + SO three 2- =BaSO three ↓ (white)

BaSO three +2HCl= BaCl two +H two O+SO two ↑

6) Ba 2+ + S two O three 2- =BaS two O three ↓ (white)

BaS two O three +2 HCl= BaCl two +H two O+SO two ↑+S↓

And S 2- 、Br - 、I - 、NO 3- 、NO 2- 、Ac - Add BaCl in two No phenomenon after.

And AgNO three Reaction of

Reaction equation:

7) 2Ag + + SO four 2- =Ag two SO four ↓ (white)

8）2Ag + + SiO three 2- =Ag two SiO three ↓ (white)

9）3 Ag + + PO four 3- =Ag three PO four ↓ (yellow)

10）2Ag + + CO three 2- =Ag two CO three ↓ (white)

11）2Ag + + SO three 2- =Ag two SO three ↓ (yellow)

12）2Ag + + 2S 2- =Ag two S ↓ (black)

13）Ag + + Cl - =AgCl ↓ (white)

14）Ag + + Br - =AgBr ↓ (yellow)

15）Ag + + I - =AgI ↓ (yellow)

Other ions such as NO three - 、NO two - 、Ac - No obvious phenomenon.

2 Volatility test

Ion to be tested: SO three 2- 、 CO three 2- 、 S two O three 2- 、S 2- 、NO two -

Reaction equation:

16）2H + + CO three 2- = H two O+CO two ↑

17) 2H + + SO three 2-= H two O+SO two ↑

18) 2H + + S two O three 2- = H two O+SO two ↑+S ↓ (yellow)

19) 2H + + S 2- = H two S↑

20) 2H + + NO two - =NO↑+ H two O

3 Redox test

Oxidation test

21） 2I - + 4H + + 2NO 2- = 2NO↑+ 2H two O+I two

Other ions have no obvious phenomenon.

Reducibility test

KMnO four test

22）2MnO four - + 5SO three 2- + 6H + =2Mn 2+ + 5SO4 2- +3H2O

23) 4MnO four - + 5S two O three 2- + 9H + = 10SO four 2- +4Mn 2+ +18H2O

24) 2MnO four - + 10Br - + 16H + =2Br two +2Mn 2+ +8H2O

25) 2MnO four - + 10 I - + 16H + =2I two +2Mn 2+ +8H2O

26) 2MnO four - + 5NO two - + 16H + = 5NO three - +2Mn 2+ +8H2O

27) 2MnO four - + 10Cl - + 16H + =5Cl two +2Mn 2+ +8H2O

28) 2 MnO four - + 5S 2- + 16H + =5S ↓ (yellow)+2Mn 2+ +8H2O

Other ions have no obvious phenomenon

I two Starch test

I two + S 2- = 2I - + S↓

I two + 2S two O three 2- = 2I - + S four O six

H two O + I two + 2SO three 2- = 2H + + 2I - + SO four 2-

matters needing attention

Observing BaS two O three During precipitation, if there is no precipitation, friction the test tube wall with glass rod to accelerate precipitation generation.

Pay attention to Ag two S two O three The color change of oxidative decomposition in air.

During the reduction test, attention must be paid to the added oxidant KMnO four And I two The amount of starch must be small, because the concentration of anions is very low. If the amount of oxidant is large, the color change of oxidant is not easy to see.

Novice on the road

Growth task Getting Started with Editing Edit Rule Edit by myself

I have questions

Content query Online Service Official post bar Feedback

Complaints and suggestions

Report bad information Failed to appeal through entries Complaint of infringement information Blocking query and unblocking

Jinggong Network Anbei No. 1100000200001