Some important Compounds of Carbon and Silicon: Have you ever built a sandcastle on the beach? Have you ever considered what sand is and why it is so abundant? So, let us tell you everything you need to know about carbon compounds and silicon compounds. Sand is in the latter category. Carbon dioxide, which plants utilise during photosynthesis, is also one of the compounds of carbon. In this article, we will learn about some important compounds of carbon and silicon.
Compounds of Carbon
Oxides of Carbon
Carbon produces a large number of oxides. Carbon monoxide \(\left({{\text{CO}}} \right)\) and carbon dioxide \(\left({{\text{C}}{{\text{O}}_2}}\right)\) are two of the most stable and important of these oxides. Carbon suboxide \(\left({{{\text{C}}_3}{{\text{O}}_2}} \right),{{\text{C}}_5}{{\text{O}}_2},\) and \({{\text{C}}_{12}}{{\text{O}}_9}\) are the three less stable oxides. Graphite oxides \({{\text{C}}_2}{\text{O}}\) and \(\left({{{\text{C}}_2}{{\text{O}}_3}} \right)\) are two others that are even less stable.
Carbon Monoxide (CO)
Preparation of Carbon Monoxide
I. It is formed by the incomplete combustion of carbon and carbon-containing fuels. This type of incomplete combustion occurs during the burning of petrol or diesel in automobiles and, therefore, \({\text{CO}}\) is always present in automobile exhausts.
\({\text{2}}\,{\text{C + }}{{\text{O}}_2} \to 2\,{\text{CO}}\)
II. In the laboratory, pure carbon monoxide is produced by dehydrating formic acid with a conc. \({{\text{H}}_2}{\text{S}}{{\text{O}}_4}\) at \(373\,{\text{k}}.\)
\(\underset{{{\text{Formic acid}}}}{\mathop {{\text{HCOOH}}}} \xrightarrow[{373\,\,{\text{K}}}]{{{{\text{H}}_2}{\text{S}}{{\text{O}}_4}}}\underset{{{\text{Carbon monoxide}}}}{\mathop {{\text{CO}}}} {\text{ + }} {{\text{H}}_2}{\text{O}}\)
III. Commercial preparation: i. It is commercially produced by passing steam over red hot cake. In this reaction, hydrogen gas is also produced.
ii. When air is utilised rather than steam, a mixture of \({\text{CO}}\) and \({{\text{N}}_2}\) is produced. This mixture is known as producer gas.
Structure of Carbon Monoxide (CO)
Carbon monoxide is iso-electronic with an \({{\text{N}}_2}\) molecule, and both have \(14\) electrons. Its electronic structure is
It is a hybrid of the following contributing structures.
Properties of Carbon monoxide
Physical properties of carbon monoxide
1. It is a colourless and odourless gas that is only slightly soluble in water.
2. It can be liquefied at \(181\,{\text{K}}\) and solidified at \(67\,{\text{K}}.\)
3. In nature, carbon monoxide is highly poisonous or toxic. Its poisonous nature arises from its tendency to combine with haemoglobin in blood to form carboxyhemoglobin.
Chemical Properties of carbon monoxide
1. Combustibility: Carbon monoxide burns in the presence of oxygen with a blue flame and forms carbon dioxide. \( 2{\text{CO}} + {{\text{O}}_2} \to 2{\text{C}}{{\text{O}}_2}\) 2. Action with litmus: Carbon monoxide is neutral to litmus. 3. Reducing nature: Carbon monoxide is a powerful reducing agent. It reduces metal oxides to the metal on heating. For example, \({\text{ZnO}} + {\text{CO}} \to {\text{Zn}} + {\text{C}}{{\text{O}}_2}\) \({\text{CuO}} + {\text{CO}} \to {\text{Cu}} +{\text{C}}{{\text{O}}_2}\) \({\text{F}}{{\text{e}}_2}{{\text{O}}_3} + 3{\text{CO}} \to 2{\text{Fe}} + 3{\text{C}}{{\text{O}}_2}\) 4. Action with sodium hydroxide: It reacts with sodium hydroxide under pressure to form sodium formate.
Uses of Carbon Monoxide (CO)
1. Carbon monoxide is a component of many fuel gases, including water gas \(\left({{\text{CO}} + {{\text{H}}_2}}\right)\) and producer gas \(\left({{\text{CO}} + {{\text{N}}_2}} \right).\)
2. It is used in nickel refining because when heated, nickel carbonyl decomposes to give metal and carbon monoxide.
3. In certain metallurgical operations, it acts as a reducing agent.
4. It is used to make a variety of useful compounds such as methyl alcohol, sodium formate, and synthetic gasoline.
Carbon Dioxide (CO2)
Carbon dioxide is a heavy colourless gas produced by the combustion of fossil fuels, the breakdown or combustion of animal and plant matter, and the act of breathing, and it is absorbed from the atmosphere by plants during photosynthesis.
Preparation:
I. It is prepared by burning carbon, fossil fuels, and other organic compounds in excess of air or oxygen.
II. In the laboratory, it is prepared by the action of dilute acids on sodium carbonates or sodium bicarbonates.
III. Commercially, \({\text{C}}{{\text{O}}_2}\) is produced as a byproduct of ammonia production. The hydrogen needed for the purpose is obtained by passing steam overheated \({\text{CO}}\) or \({\text{C}}{{\text{H}}_4}.\)
It is also formed during the manufacture of lime or ethyl alcohol by fermentation of glucose or fructose.
Structure of Carbon dioxide (CO2)
Carbon dioxide is a linear molecule as it has zero dipole moment. Its electronic structure may be represented as:
According to the above structure, the \({\text{C}} = {\text{O}}\) bond length should be \(110\,{\text{pm}},\) but it is actually \(115\,{\text{pm}}.\) This means that a simple double-bonded structure is insufficient to represent the molecule, and it is a hybrid of the following contributing resonating structures.
Properties of Carbon Dioxide
Physical properties
I. It is colourless and odourless and is \(1.5\) times heavier than air.
II. Carbon dioxide is fairly soluble in water, and its solubility increases as pressure is increased.
III. Carbon dioxide, unlike carbon monoxide, is not poisonous. However, both humans and animals die in the carbon dioxide atmosphere due to a lack of oxygen.
IV. Under \(50\) to \(60\) atmospheres of pressure, carbon dioxide can be liquefied at room temperature. When liquid carbon dioxide is suddenly evaporated, it solidifies into a snow-like mass known as dry ice.
Chemical Properties
I. Combustibility: Carbon dioxide is neither combustible nor support of combustion. However, a number of burning metals such as sodium, potassium, magnesium, and others continue to burn in a carbon dioxide jar. \(2{\text{Mg}} + {\text{C}}{{\text{O}}_2} \to 2{\text{MgO}} + {\text{C}}\) II. Acidic nature: Carbonic acid is formed in an aqueous solution of carbon dioxide, making it weakly acidic. Because it is a dibasic acid, it produces two types of salts when it reacts with bases. \({\rm{C}}{{\rm{O}}_2} + {{\rm{H}}_2}{\rm{O}}\, \to \,\mathop {{{\rm{H}}_2}{\rm{C}}{{\rm{O}}_3}}\limits_{{\rm{Carbonic}}\,\,{\kern 1pt} {\rm{acid}}} \) III. Action with lime water: When \({\text{C}}{{\text{O}}_2}\) is passed through lime water, the formation of insoluble calcium carbonate causes the lime water to turn milky. \(\mathop {{\rm{Ca}}{{\left( {{\rm{OH}}} \right)}_{\rm{2}}}}\limits_{{\rm{Lime}}\,\,{\rm{Water}}} \,{\rm{ + }}\,{\rm{C}}{{\rm{O}}_{\rm{2}}}\, \to \,\mathop {{\rm{CaC}}{{\rm{O}}_{\rm{3}}}}\limits_{\left( {{\rm{Insoluble}}} \right)} \,{\rm{ + }}\,{{\rm{H}}_{\rm{2}}}{\rm{O}}\)
Uses of Carbon Dioxide (CO2)
I. In aerated waters, carbon dioxide is used to make cold drinks.
II. It is used in fire extinguishers since it does not support combustion.
III. It is utilised in the production of sodium carbonate and white lead.
IV. Carbon dioxide is used in the production of urea \(\left({{\text{N}}{{\text{H}}_2}{\text{CON}}{{\text{H}}_2}} \right),\) a highly useful fertiliser.
V. It is a refrigerant that comes in the form of dry ice.
VI. Carbon monoxide poisoning victims are given carbogen, a mixture of carbon dioxide \(\left({5\% } \right)\) and oxygen \(\left({95\% } \right)\) for artificial respiration.
Compounds of Silicon
Silicon Dioxide (SiO2)
Silica and silicates make up \(\left({95\% }\right)\) of the Earth’s crust. Silicon dioxide, also known as silica, exists in a variety of crystallographic forms. Some of the crystalline forms of silica are quartz, cristobalite, and tridymite, which are interconvertible at appropriate temperatures. Silicon dioxide is a three-dimensional covalent network solid in which each silicon atom is covalently bonded to four oxygen atoms in a tetrahedral fashion. As shown in the diagram, each oxygen atom is covalently bonded to another silicon atom. Each tetrahedron shares a corner with another. The entire crystal can be thought of as a giant molecule with eight-membered rings made up of alternate silicon and oxygen atoms.
Properties of Silicon Dioxide
Silica in its normal form is almost non-reactive because of very high \({\text{Si}} – {\text{O}}\) bond enthalpy. Even at high temperatures, it is resistant to halogens, dihydrogen, and the majority of acids and metals. It is, however, attacked by \({\text{HF}}\) and \({\text{NaOH}}.\)
\({\text{Si}}{{\text{O}}_2} + 2{\text{NaOH}} \to {\text{N}}{{\text{a}}_2}{\text{Si}}{{\text{O}}_3} + {{\text{H}}_2}{\text{O}}\)
\({\text{Si}}{{\text{O}}_2} + 4{\text{HF}} \to {\text{Si}}{{\text{F}}_4} + 2{{\text{H}}_2}{\text{O}}\)
Uses of Silicon Dioxide
Quartz is widely used as a piezoelectric material, enabling the development of highly accurate clocks, modern radio and television broadcasting, and mobile radio communications.
As a drying agent and as a support for chromatographic materials and catalysts, silica is used.
In filtration plants, kieselguhr, an amorphous form of silica, is used.
Silicones
Silicones are synthetic organosilicon polymers containing repeated \({{\text{R}}_2}{\text{SiO}}\) units held by \({\text{Si-O-Si}}\) linkages.
Preparation
When methyl chloride reacts with silicon in the presence of copper as a catalyst at \(570\,{\text{k}},\) various types of methyl-substituted chlorosilanes of formula \({\text{C}}{{\text{H}}_3}{\text{SiC}}{{\text{l}}_3},{\left({{\text{C}}{{\text{H}}_3}} \right)_2}{\text{SiC}}{{\text{l}}_2}),{\left({{\text{C}}{{\text{H}}_3}} \right)_3}{\text{SiCl}}\) along with a small amount of \({\left({{\text{C}}{{\text{H}}_3}}\right)_4}{\text{Si}}\) are formed. Hydrolysis of dichlorodimethylsilane followed by polymerisation yields straight chain polymers.
Properties and Uses
Silicones with short-chain molecules behave as oily liquids; silicones with medium-chain molecules behave as viscous oils, jellies, and greases; and silicones with very long chains behave as rubbery elastomers and resins.
They are chemically inert, which means they are resistant to oxidation, thermal decomposition, and attack by organic reagents/chemicals.
Silicones are water repellent in nature because they are surrounded by non-polar alkyl groups.
It is used for making waterproof papers, wool, textiles, wood, etc., by coating them with a thin film of silicone.
It is used as sealants and electrical insulators.
As lubricants at high as well as low temperatures since there is little change in their viscosities with temperatures.
Being biocompatible, they are used in surgical and cosmetic implants.
Silicates
Silicates are the compounds in which the anions present are either discrete \({\text{Si}}{{\text{O}}_4}^{4 – }\) tetrahedra or a number of such units joined together through corners.
There are numerous silicate minerals found in nature. Some of these important minerals are feldspars, i.e., Albite \({\text{NaAIS}}{{\text{i}}_3}{{\text{O}}_8},\) zeolites, e. g., chabazite micas (muscovite) \(\left[{{\text{KA}}{{\text{I}}_2}\left({{\text{S}}{{\text{i}}_3}{\text{AI}}{{\text{O}}_{10}}} \right){{\left({{\text{OH}}} \right)}_2}} \right]\) and asbestos \(\left[ {{\rm{M}}{{\rm{g}}_3}\left( {{\rm{S}}{{\rm{i}}_2}{{\rm{O}}_5}} \right){{\left( {{\rm{OH}}} \right)}_4}} \right].\) The \({\text{Si}}{{\text{O}}_4}^{4 – }\) tetrahedra are the basic structural unit in silicates. In addition to these natural silicates, some artificial silicates have been prepared. For example, the two important man-made silicates are glass and cement.
Structure \(\left({\text{a}} \right)\) represents the tetrahedral structure of \({\text{Si}}{{\text{O}}_4}^{4 – }\) and structure \(\left({\text{b}} \right)\) is the projection formula of \({\text{Si}}{{\text{O}}_4}^{4 – }\) in which small open circles represent oxygen atoms, and the small closed circle inside represents the silicon atom.
Zeolites
When some of the silicon atoms in a three-dimensional network silicate are replaced by \({\text{A}}{{\text{l}}^{3 + }}\) ions, the resulting structure has a negative charge and is known as an aluminosilicate. As a result, some cations, such as \({\text{N}}{{\text{a}}^ + }\) or \({\text{C}}{{\text{a}}^{2 + }},\) are incorporated into the structure to balance the negative charge. Feldspar \(\left({{\text{KAlS}}{{\text{i}}_3}{{\text{O}}_8}} \right)\) and zeolites \(\left({{\text{NaAlS}}{{\text{i}}_2}{{\text{O}}_6}.{{\text{H}}_2}{\text{O}}} \right)\) are examples of three-dimensional aluminosilicates.
Uses of Zeolites
1. Zeolites are widely used as catalysts in the petrochemical industry for hydrocarbon cracking and isomerisation. For example, \({\text{ZSM}} – 5\) (a type of zeolite) is used to directly convert alcohol to gasoline.
2. Permutit, a hydrated zeolite, is used as an ion exchanger in hard water softening.
Summary
Carbon monoxide \(\left({{\text{CO}}} \right)\) and carbon dioxide \(\left({{\text{C}}{{\text{O}}_2}} \right)\) are two of the most stable and important oxides of carbon. \(\left({{\text{CO}}} \right)\) is formed by the incomplete combustion of carbon and carbon-containing fuels. Carbon monoxide is highly poisonous or toxic. Carbon dioxide is a heavy colourless gas produced by the combustion of fossil fuels, the breakdown or combustion of animal and plant matter, and the act of breathing, and it is absorbed from the atmosphere by plants during photosynthesis. Silica and silicates make up \(95\% \) of the Earth’s crust. Silicon dioxide, also known as silica, exists in a variety of crystallographic forms.
FAQs on Some Important Compounds of Carbon and Silicon
Q.1. What are some Important Compounds of Carbon and Silicon? Ans: Some important compounds of Carbon and Silicon are as follows: Important compounds of carbon are carbon dioxide and carbon monoxide. Important compounds of silicon are silicon dioxide \(\left({{\text{Si}}{{\text{O}}_2}} \right),\) silicates etc.
Q.2. What are the important carbon compounds? Ans: Carbon monoxide \(\left({{\text{CO}}} \right)\) and carbon dioxide \(\left({{\text{C}}{{\text{O}}_2}} \right)\) are two of the most stable and important oxides of carbon.
Q.3. What are five compounds that contain carbon? Ans: The five compounds that contain carbon are carbon monoxide \(\left({{\text{CO}}} \right)\) and carbon dioxide \(\left({{\text{C}}{{\text{O}}_2}} \right),\) Carbon suboxide \(\left({{{\text{C}}_3}{{\text{O}}_2}} \right),{{\text{C}}_5}{{\text{O}}_2},\) and \({{\text{C}}_{12}}{{\text{O}}_9}.\)
Q.4. Why are silicones very valuable compounds? Ans: Silicones are very valuable compounds because silicones are resistant to oxidation and other chemicals and have high thermal stability. This compound is used as an electrical insulator. It is also widely used in surgeries.
Q.5. What are the five uses of silicon? Ans: Five uses of silicon are as follows: 1. The element is a key component of ceramics and bricks. 2. Silicon is utilised in the manufacture of fire bricks. 3. Silicon is a material that is widely used in computer chips and solar cells. 4. The element is used to make transistors because it is a semiconductor. 5. It’s a necessary component of Portland cement.
Scan to Download the App 
JEE Main