Co-ordinate Or Co-ionic And Metallic Bonding

Co-ordinate Or Co-ionic And Metallic Bonding

Previous Topic Ionic And Covalent bonding

Last class we explain the definition, differences and examples of ionic and covalent bonds, I hope you understand, but if you don't, you should always know that you are free to ask.

So straight to today's topic

Co-ionic Or Co-ordinate Covalency Bond

Co-ionic or co-ordinate bond combines the principle of both covalent and ionic bonding.

For example, Ammonia (NH3),
In the formation of ammonia, three hydrogen atoms share three pairs of electrons with a nitrogen atom by normal covalent bonding.

Nitrogen atom has a lone pair of electron in its outermost shell and shares the outermost electron with proton (hydrogen ion). Do you know how many forms hydrogen can take? If you don't, don't worry, i will explain it before the end of the session (please remind me).

The hydrogen ion, from an acid to produce ammonium ion [NH4].

The proton combining with the NH3 molecule carries over its positive charge to form ammonium ion [NH4].


The ammonia molecule also react in the preparation of tetraamine copper (ii) ion which gives blue precipitate when excess of ammonia is added to a solution of copper (ii) salt (e.g copper (ii) tetraoxosulphate (vi) by co-ordinate bonding.

Brief : After this topic, we will analyze salt analysis or should we postpone till after salt.

Formation Of Tetraamine Copper (ii)

During the reaction, copper (ii) tetraoxosulphate (vi) (CuSO4), the copper has valency of two which is transferred to (SO4)2- ion and the outer electron shell of copper ion is empty. Four NH3 (ammonia) molecules form co-ordinate bonds with Cu2+ ion by means of their lone pair electrons to form a shared electron octet in the empty valency electron shell of copper (ii) ion.


The bonding can also be represented as below:


Note : anytime you see a charge either positive or negative on a compound, it is always likely to be co-ionic or co-ordinate compound.

Brief : Ammonia is NH3 and ammonium is NH4, don't miss it up.

Metallic Bond

Metallic bond is the bond that holds or join atoms together in a metal.
During metallic bonding, each metallic atom contributes its valence electrons to the electron cloud by becoming positively charged. The ions are held together in the lattice by the electron cloud.

The larger the number of electrons in the outermost shell of the metal, the stronger the bonding between them. This type of bonding is very strong in some metals such as iron (Fe) which are difficult to cut and much weaker in some metals such as potassium (K) or sodium (Na) which can be cut with a knife.


When a force is applied to metallic bonding elements, the layers of the metallic ions can slide over one another without shattering the crystal lattice, This is because there are no rigid, directed bonds in a metallic crystal.

The bonding components is a moving electron cloud which can easily react by adjusting itself when the metallic layers achieve a new stable arrangement.

Note : that, flow layer of metallic ion slides when a force is applied and the sliding action can be hindered by the addition of a small amount of another metal.



Before Sliding




After Sliding



That is all on Co-ordinate Or Co-ionic And Metallic Bonding, our next topic is hydrogen bonding and vander waal's force.

Hydrogen Bonding And Vander Waal's Force

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