Halides of Group 14

Halides include two elements, of which one element is a metal and the other may be a halogen compound. For example, some of group-14 halides are CCl4, SiCl4, SiBr4, similierly in this article, we will learn about more details about halides of group 14. The group 14 is also known as the Carbon family. They have four electrons in their outermost shell. 

Define Halides of Group 14

There are two types of halides in group 14, which are known as MX2 and MX4. The top of the group is dominated by M(IV) halides, whereas the bottom of the group is dominated by the M(II). In all the M(IV) halides MX4 (M = C, Si, Ge; X = F, Cl, Br, I), the top three elements are carbon, silicon, and germanium. Consequently, as the group is descended, the stability of the M (II) state increases over the M(IV) state. While none of the dihalides MX2 exist independently for carbon or silicon, most of the divalent halides MX2 for germanium exist in addition to the germanium tetra halides. The most stable lead halides are PbX2, and the only known tetra halide is PbCl4 (which breaks down exothermically to lead chloride and chlorine gas). 

Halides of Group 14 – an overview of compounds of Group 14

Hybrides – If we talk about the elements of group 14, all the elements form covalent hydride in this group except for lead. Lead is the only one, which forms ion hydrides. In this group, the stability and the ease of formation decreases from C to Pb. Hydrides of carbon are the most stable one, and they are easy to synthesise in comparison to any other elements of this group. 

Moving over to other compounds of group 14. The most common halides are tetra halides, and they are covalent in nature. 

Carbon – CH₄

It is highly reactive, and it is exceptionally unreactive. It has a melting point of -183.5 C, properties of which resembles that of ethane. It can be prepared by fluorination. CCl4 is an important element, which is best for industrial use, and it acts as a common lab solvent. The physical properties are that it is colourless and volatile in nature. It is not soluble in water but can easily be soluble in alcohol, ether, etc. Although it is generally chemically inert but under drastic conditions it becomes vapour after reacting with steam above 300 оC to form phosgene(COCl2), which is the poisonous gas that was used in World War 1. 

CHCl3 + ½ O2  → COCl2 + HCl

It undergoes reduction in the presence of moist, and it will get converted to chloroform, which is another important solvent. 

CH4 + Cl2/h٧ ⟶ CH3Cl + HCl

CH3Cl + Cl2/h٧ ⟶ CH2Cl2 + HCl

CH2Cl2 + Cl2/h٧ ⟶ CHCl3 + HCl

When it undergoes substitution reaction it produces Freon’s, they are used as refrigerants and aerosol propellants. The most common one is dichlorodifluoromethane. 

CCl4 + HF ⟶ 2HCl + CCl2F2

CBr4, which is a pale yellow solid, is less stable in nature. It is prepared from the bromination of methane. 

CCI4 is a crystalline bright red solid, which is the least stable. 

Now, talking about Silicon Halides – it undergoes hydrolysis. It is colourless and is volatile in nature. General formula of silicon halide is SiX4 and mixed halides of silicon are also found in nature.

For example

SiF4 is gas in nature at room temperature.

SiCl4 and SiBr4 are liquid at room temperature.

SiI4 is solid in nature

If we look in depth, the halide can be divided into two categories, namely, ionic and covalent. In the case of ionic halides, the halogen focuses on forming the nearest electronic configuration of the noble gas by borrowing or lending one electron from the atom M. The covalent halides are often called acid halides.

Conclusion

MX2 and MX4 are the two feathers of halides recognized for this order. The highest of the group is dominated by M (IV) halides, whereas M (II) halides dominate the gemstone bottom. The three basic carbon, silicon, and germanium at the highest of the M (IV) halides MX4 (M = C, Si, Ge; X = F, Cl, Br, I) are known. Still, when the group descends, the M (II) state’s stability rises compared to the M (IV) state. In addition to the germanium tetrahalides, none of the dihalides MX2 live singly for carbon or silicon, but the majority of the divalent halides MX2 are known for germanium.