Binary compound

Chemical terminology

Collection

zero Useful+1

zero

This entry is made by Compilation and application of scientific encyclopedia entries of "Science Popularization China" to examine.

Binary compounds (binary compounds) refer to those containing two different element Of chemical compound 。 for example water H two O、 sodium chloride NaCl、 alumina Al two O three 、 hydrogen sulfide H two S, etc. Each compound has certain characteristics, which are different from the elements or ions it contains, as well as from other compounds. There are millions of known compounds, some of which exist in nature, others are synthetic.

Chinese name: Binary compound
Foreign name: Binary compound
Definition: Composed of two elements chemical compound

Example: Silver bromide AgBr、 Water H2O
Subclass: Oxide, carbide, etc
Nature: chemical compound

catalog

definition

Announce

edit

Binary compounds mainly refer to inorganic compound The middle molecule is composed of two types element A compound of composition, or chemical formula Containing only two elements chemical compound 。 Such as sodium chloride NaCl Silver bromide AgBr、 Water H ₂ O, etc. The naming of binary compounds is to use the word "Hua" in the middle of the names of the two elements. The names of negative elements are put first, and the names of positive elements are put after.

Customary naming

Announce

edit

Generally speaking, the naming of binary compounds follows two forms:

"Make a certain" - if the Valence state Are the most common valence states, and the naming will not lead to ambiguity. It is customary to put elements with negative valence first when naming them. For example: sodium chloride —NaCl Potassium sulfide - K2S When there are many valence changes of elements in the compound, or the valence state of the element is not the main valence state, the above naming will lead to ambiguity. At this time, three methods can be used to solve the problem: "how to change something". For example: Dioxygen difluoride —O2F2 Tetranitrotetrasulfide - S4N4 "XX ()", in parentheses Roman numerals Written Oxidation number 。 Commonly used for naming Ionicity Stronger compounds. For example: Titanium chloride (IV) —TiCl4 Titanium chloride (III) - TiCl3 "certain high/sub certain" is used for elements with relatively fixed variable valence state. Common elements named in this way include: Fe - iron ； Fe— ferrous Cu— copper ； Cu cuprous Co high cobalt; Co - cobalt Hg - mercury; Hg - mercurous Tl - thallium/high thallium; Tl Thallite Sn Tin/high tin; Sn - stannous Mn - high manganese; Mn - manganese.^[1]

Variable metal

Announce

edit

Latin expression Metal Latin name+"- ic" (for high price)/"- ous" (for low price)+non-metal+"- ide" For example: Ferrous chloride —Ferrous chloride， Cuprous chloride - There are only about 10 kinds of Cuprus chloride dicarboxylic acid (aqueous solution) "Hydro -"+nonmetal+"- ic"+"acid" Nonmetal Can form with hydrogen binary Acid (binary here does not mean ionization The number of hydrogen atoms in the acid): chlorine fluorine 、 bromine 、 iodine And sulfur, etc. Their names can be indicated by the following formula: for example: hydrochloric acid —Hydrochloric acid， hydrofluoric acid —Hydrofluoric acid

binary Covalent compound

Nonmetal+nonmetal+"- ide" add an appropriate Latin prefix before the element to express the number of atoms of an element in the compound molecule. This method is not usually used in Ionic compound Medium (below). For example, K2O is generally not called a Dipotassium oxide, but simply called a Potassium oxide. P4O6, however, is called tetraphophorus hexoxide. Some with vowel The beginning element name (for example oxygen Oxygen）， You need to cancel the last letter of the prefix and use the first letter of the element name, such as mono -+Oxide=Monoxide O4 = Tetroxide、O5 = Pentoxide， And so on.

If the first element is a single atom, "mono -" cannot be added.

one	Mono-	three	Tri-	five	Penta-	seven	Hepta-	nine	Nona-
two	Di-	four	Tetra-	six	Hexa-	eight	Octa-	ten	Deca-

For example: Phosphorus pentafluoride —Phosphorus pentafluoride， Iodine heptafluoride —Iodine heptafluoride

binary Ionic compound

Monoatomic anion: cation + anion +"Ide" for example: Magnesium sulfide —Magnesium Sulfide

Thermal stability of binary compounds

When a compound is heated, due to the intensification of the outer electron vibration, the electron cloud strongly leans towards the positive ion side. If the deformation of the negative ion is large enough, one or several electrons of the negative ion can cross the repulsion force of the positive ion shell electron and enter the atomic orbit of the positive ion and become its own, which is accompanied by the decomposition of the compound. Such as copper halide Thermal decomposition reaction by

2CuX2=2CuX+X2

The greater the mutual polarization, the lower the decomposition temperature. See the following data:

chemical compound	CuF2	CuCl2	CuBr2	CuI2
Decomposition temperature/℃	nine hundred and fifty	five hundred	four hundred and ninety	non-existent

^[2]

oxide

Announce

edit

A binary compound formed by oxygen and other elements. as calcium oxide 、 sulfur dioxide 、 nitric oxide Etc. Oxides can be divided into Unsalted oxide (e.g carbon monoxide , nitric oxide, etc.) and salt forming oxides, the latter being divided into Alkaline oxide (such as calcium oxide) Amphoteric oxide (such as alumina) and Acid oxide (e.g carbon dioxide )。 Besides peroxide 、 Superoxide , ozone oxides, etc. The same element often has several oxides with different valence states, such as SO two And SO3, FeO, Fe two O three And Fe three O four Etc. Sometimes oxides have a broader meaning, not limited to binary compounds containing oxygen elements, such as multi oxides (such as NiFe two O four ）And organic oxides (e.g. ethylene oxide C two H four O， I.e ethylene oxide ）Etc.

Except for helium, neon and krypton, all elements can form oxides and easily show the highest oxidation state of elements. According to the characteristics of valence bond, it can be divided into ionic oxides (such as sodium oxide) and covalent oxides (such as carbon dioxide, beryllium oxide); It can be divided into oxide peroxide 、 Superoxide , ozone oxides, etc; It can be divided into alkaline oxides (such as calcium oxide), acidic oxides (such as sulfur trioxide) Amphoteric oxide (such as zinc oxide, aluminum oxide), as well as neutral oxides, also known as inert oxides (such as carbon monoxide, nitric oxide), which are insoluble in dilute acid and alkali; In addition, it can also be divided into metal oxides (such as sodium oxide), non-metallic oxides (such as nitrogen dioxide), mixed oxides (such as ferric oxide), and non stoichiometric oxides (such as FeO zero point nine zero ，FeO zero point nine five ）Etc. Modern research on mixed oxides shows that, Ferric tetroxide 、 Lead tetroxide Actually, it is iron (Ⅲ) acid FeFe [FeO four ]And lead (IV) acid lead (II) Pb two [PbO four ]Is salt, which is also called pseudo oxide. Non stoichiometric oxides are usually formed by arranging O in close packed order and filling some gaps with metal ions. When an element can form several oxides, the highest oxidation state is generally acidic, and the low oxidation state is alkaline, such as chromium oxide CrO (alkaline) Chromium trioxide Cr two O three (Gender) and Chromium trioxide CrO three (acidic). Peroxide contains O two , can be regarded as hydrogen peroxide The highly electropositive alkali metals, calcium, strontium and barium can form ionic peroxides, Sodium peroxide Absorb air carbon dioxide Release oxygen. Superoxide contains superoxide ion O two , potassium, rubidium, cesium, calcium, strontium and barium can form MO two Or MO four They are easy to absorb moisture, and release oxygen when heating, and also release oxygen when encountering water and dilute acid. Ozone oxide contains ozone ion O three Alkali metals, alkaline earth metals, and ammonium ions can all form ozone oxides, which are typical salts and easy to decompose. For example, potassium ozone can be decomposed into potassium oxide and oxygen, which are highly oxidizing. All kinds of oxides have very important applications in practice. All Short period element The characteristic oxides of are colorless, and the oxides of many elements in a long period are colored. The oxides in the low oxidation state have more colors. The oxides of beryllium, magnesium, calcium, zirconium, hafnium and thorium have the highest melting point, between 2500 and 3000 ℃, and are mostly used as High temperature resistant material 。

carbide

Announce

edit

It refers to the binary compound formed by the combination of carbon and elements with smaller electronegativity or similar electronegativity, excluding the compound formed by carbon and oxygen, sulfur, phosphorus, nitrogen and halogen. According to the characteristics of bonding, carbides can be divided into three types: ionic, covalent and interstitial.

① Ionic carbides are also called salt like carbides. It is mainly a binary compound formed by the elements of group Ⅰ A, Ⅱ A, Ⅲ A, Ⅰ B, Ⅱ B (except Hg) and some f transition elements (the f layer is not filled with electrons) with carbon. Some contain C and C two 。 Carbides containing C give off methane during hydrolysis, which can be called methanation, such as beryllium carbide Be two C and aluminum carbide Al four C three , the hydrolysis formula of the latter is:

Al four C three +12H two O=4Al(OH) three +3CH four

With C two When hydrolyzed, acetylene is released, which is also called acetylene compound. For example:

CaC two +2H two O=HCCH+Ca(OH) two

② Interstitial carbides are also called metal carbides. Mainly d Transitional element Especially the binary compounds formed by Ⅵ B, Ⅶ B and iron elements and carbon. The structural feature is that carbon atoms occupy octahedral holes closely arranged by metal atoms. It is characterized by very high melting point (3000~4800 ℃) and high hardness（ Mohs hardness 7~10) and has metal conductivity. For metals with atomic radius greater than 130pm, the insertion of carbon atoms will not deform the metal lattice, but only further strengthen the lattice, thus increasing the hardness and melting point. For metals with atomic radius less than 130pm, such as chromium, manganese, iron, cobalt and nickel, the metal lattice is obviously distorted. The carbide properties of these metals are between ionic and interstitial, and they are easy to be hydrolyzed by water and dilute acid to generate hydrocarbons and hydrogen.

③ The covalent carbides are mainly silicon and boron carbides. Carbon atom and silicon Boron atom The electronegativity of chemical compound They are characterized by high hardness, high melting point and stable chemical properties.

Calcium carbide in ionic carbide is acetylene and others Chemical Reagents Important raw materials. Interstitial carbides have high hardness and good conductivity. For example, tungsten carbide and tantalum carbide are alloys Ceramic composites Important components of. Covalent boron carbide and silicon carbide have been used as abrasives. It is generally through carbon and metal or metallic oxide Reaction at high temperature of 1000~2800 ℃ to produce carbide; In some cases, it is prepared by reducing metal oxides or chlorides with hydrocarbons or hydrogen.^[3]

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