What are ionic compounds 10 examples?

Ionic compounds are compounds consisting of ions.

Two-element compounds are usually ionic when one element is a metal and the other is a non-metal. Examples include:

• sodium chloride: NaCl, with Na+ and Cl- ions
• lithium nitride: Li3N, with Li+ and N3- ions
• magnesium oxide: MgO, with Mg2+ and O2- ions
• calcium phosphide: Ca3P2, with Ca2+ and P3- ions

Ionic compounds can be more complicated than the two-element ones listed above. Examples of polyatomic ionic compounds include:

• sodium sulfate: Na2SO4, with Na+ and SO42- ions
• ammonium thiocyanate: NH4SCN, with NH4+ and SCN- ions
• potassium hydroxide: KOH, with K+ and OH- ions
• ammonium carbonate: (NH4)2CO3, with NH4+ and CO32- ions

Although they consist of positively and negatively charged ions, ionic compounds are electrically neutral, because the charges are always equal and opposite.

(The other major group of compounds is molecular compounds: these consist of molecules rather than ions.)

Bonding in Ionic Compounds

In its purest form, ionic bonding is not directional. It can be regarded as simple positive-negative Coulombic attraction between point charges. This is different from covalent bonding, in which electrons are shared by atoms, forming directional bonds.

However, absolutely pure ionic bonding does not exist. There is always at least a small degree of covalent bonding character in ionic compounds.

The Formulas and Structures of Ionic Compounds

The unit cell of fluorite, CaF2. Million upon million of repeated translations of this unit cell in 3-dimensions produces a visible crystal of fluorite.

In a molecular compound, such as, for example, water, H2O, or ethanol, C2H5OH, each unit of the substance, the molecule, consists of the number of atoms shown in the formula.

In an ionic compound, such as common salt, NaCl, or magnesia MgO, the formula tells us the correct ratio of elements present, but it does not specify the unit. Ionic compounds exist as giant crystal lattices.

Each crystal contains an unspecified number of ions: the numbers are enormous: even a 0.5 gram crystal of sodium chloride contains about 1 x 1022 ions.

The structures of crystals can be understood in terms of their repeating units - unit cells: these can be determined by X-ray diffraction measurements.

Copper(II) sulfate hydrate crystals CuSO4·5H2O.
Image by Crystal Titan.

Crystals of sodium chloride, NaCl, magnified.

In general, ionic solids do not carry electric current, because the ions are in fixed positions in the crystal lattice. They do, however, conduct electricity when molten or when dissolved in solution, when the ions are released from the crystal lattice and become mobile.

Solutions of Ionic Compounds

Ionic compounds dissolve best in polar solvents. Examples of polar solvents are water, methanol, and formamide.

Ionic compounds are insoluble or have very low solubility in non-polar solvents. Examples of non-polar solvents are hydrocarbons, and chloroform.

Solvation
For an ionic compound to dissolve, the electrostatic bonds holding the ions in their rigid crystal lattice must be replaced by attractions between ions and solvent molecules. Each ion becomes surrounded by solvent molecules, as shown in the diagram.

Solvation of ionic compounds in polar solvents is driven by a decrease in free energy.

When NaCl dissolves in water, the polar water molecules form solvation shells around the dissolved ions. Here, water's oxygen atoms, each with a slight negative charge, solvate the Na+

Likewise, the Cl- is surrounded by water molecules with their slightly positive hydrogen atoms oriented to the Cl-.

Bronsted Lowry acids/bases are substances that can donate/accept H+ ions.

Substances containing H+ ions are classed as acids.

H+ acceptors such as OH- and O2- are classed as bases.

Here are examples of ionic bonds and ionic compounds:

NaBr: sodium bromideKBr: potassium bromideNaCl: sodium chlorideNaF: sodium fluorideKI: potassium iodideKCl: potassium chloride

CaCl2: calcium chloride

Note that ionic compounds are named with the cation or positively-charged atom written before the anion or negatively-charged atom. In other words, the element symbol for the metal is written before the symbol for the nonmetal.

You can recognize ionic compounds because they consist of a metal bonded to a nonmetal. Ionic bonds form between two atoms that have different electronegativity values. Because the ability to attract electrons is so different between the atoms, it's like one atom donates its electron to the other atom in the chemical bond.

In addition to ionic bond examples, it may be helpful to know examples of compounds that contain covalent bonds and also compounds that contain both ionic and covalent chemical bonds.

All the matter present in the universe is made up of some combination of 118 elements we see on the periodic table. Chemical bonding is a key concept in chemistry to understand how these elements join together to form various compounds. It is a well-established fact that opposite charges attract each other via a simple electromagnetic force. Hence, the negatively charged electrons that are orbiting the nucleus and the positively charged protons in the nucleus attract each other. An electron positioned between two nuclei will be attracted to both of them, and the nuclei will be attracted toward electrons in this position. Therefore, in simple terms, a chemical bond is known as a mutual attraction between two or more atoms that results in the redistribution of their outermost valance electrons. The type of chemical bond formed depends upon the elements involved and their corresponding properties. One of such properties is electronegativity. It is the measure of the tendency of an atom to attract the shared pair of electrons. The bond formed between oppositely charged ions, or two atoms due to a significant difference between their electronegativities, is known as an ionic bond. It is one of the main types of chemical bonding along with covalent bonding and metallic bonding.

Ionic bonding tends to occur between electropositive metals and electronegative non-metals. When ionic bonds form, a metal donates one or more electrons, due to having a low electronegativity, to form a positive ion or cation. The non-metal atom has a high electronegativity, and therefore, it readily gains electrons to form a negative ion or anion. The two ions are then attracted to each other by electrostatic forces. The interspersing of positive and negative ions allows the ions to come close together until the repulsions balance the attractions. However, it is important to understand that electrons do not make a complete transfer from one atom or molecule to the other. In fact, all ionic compounds have some degree of electron sharing (covalent nature). Therefore, the term “ionic bond” is given when the ionic character is large enough to dominate over the polar covalent character. Moreover, Ionic compounds tend to form a crystal structure rather than being a molecule. Let’s discuss a few examples of ionic bonding in daily life.

1. Table Salt

(Left) NaCl, a typical ionic compound. (Right) In the crystal structure of sodium chloride, the purple spheres represent sodium cations, and the green spheres represent chloride anions

Perhaps the most common ionic compound people come across every day is table salt. The chemical name of table salt is sodium chloride, NaCl. It has a cubic unit cell. NaCl is best thought of as a face-centered cubic array of anions with an interpenetrating fcc cation lattice (or vice-versa). The cell looks the same whether you start with anions or cations on the corners. Each ion is 6-coordinate and has a local octahedral geometry. NaCl forms easily through the combination of its component elements sodium and chlorine.

{2Na} (s) + {Cl}_{2} (g)  →  2 NaCl

The reaction is extremely exothermic, producing a bright yellow light and a great amount of heat energy. The attractions between the {Na}^{+} and {Cl}^{-} ions in the solid are so strong that only highly polar solvents, like water, dissolve NaCl well. Salt plays a crucial role in maintaining human health. It is the main source of sodium and chloride ions in the human diet. Sodium is essential for nerve and muscle function and is involved in the regulation of fluids in the body. Whereas, chloride ions serve as important electrolytes by regulating blood pH and pressure.

2. Iodized Salt

Iodine is one of the essential dietary minerals that is required in the human body for normal thyroid function, growth, and cognitive development. Worldwide, around 1.9 billion people suffer from iodine deficiency and almost a quarter of which are school-aged children. To overcome these challenges, governments around the globe launch several awareness campaigns promoting the use of iodized salt over plain salt. Iodized salts are a mixture of table salt with some salt of iodine, most commonly potassium iodide (KI). Since it can be added to a common food item without altering the taste, it is an easy way to get iodine in the diet. Potassium Iodide (KI) is produced using elemental iodine and potassium hydroxide, or in more scientific terms:

3{I}_{2} + 6KOH → 5KI + {KIO}_{3} +3{H}_{2}{O}

The ions {K}^{+} and {I}^{-} combines via ionic bonding to form KI, and has a similar crystal structure as sodium chloride NaCl. KI also serves as a source of iodine in many organic syntheses, distinctively in the preparation of aryl iodides from arene diazonium salts. Nonetheless, the overdose of KI can also lead to some health complications such as triggering and/or worsening hyperthyroidism and hypothyroidism, and then cause temporary or even permanent thyroid conditions.

On average, human beings spent around 3-5 minutes daily brushing their teeth. For some people, brushing their teeth early in the morning helps them wake up properly, while others prefer to brush their teeth before going to bed in order to avoid the damage caused by bacteria. Nonetheless, brushing teeth is equally important to every human being. However, the difference may occur in the choice of their toothpaste. When you walk through the aisle of toothpaste in the store, you come across several variants such as anti-cavity toothpaste, toothpaste with salts, whitening toothpaste, sensitivity toothpaste, etc. All of these variants have fluoride as a common ingredient. The use of fluoride toothpaste is an important public health measure to both prevent and reduce the severity of dental caries in all age groups. The efficacy of fluoride as a caries preventive agent depends largely on its concentration and availability in the oral fluids to affect the demineralization and remineralization balance. Fluorides are delivered through toothpaste and oral fluid as a salt named sodium fluoride, NaF. Sodium fluoride in toothpaste and mouthwash safely and effectively helps to prevent tooth decay, when formulated correctly and used as directed. It is an inorganic ionic compound, dissolving in water to give {Na}^{+} and {F}^{-} ions, and has a crystal structure similar to NaCl where both {Na}^{+} and {F}^{−} occupy octahedral coordination sites.

4. Baking Soda

Baking soda is another most commonly found chemical in a household, specifically in the kitchen. It is one of the most vividly used leavening agents used in baking goods to improve their texture and appearance. In chemistry, it is known by the name sodium bicarbonate (IUPAC name: sodium hydrogen carbonate) and exists in nature as a crystalline structure, nahcolite, which is later ground to form a fine- powdered baking soda. It is an alkaline chemical compound with the formula {NaHCO}_{3}. Sodium cation {Na}^{+} and a bicarbonate anion {HCO}_{3}^{-} are held together via ionic bonding to form this salt. Sodium bicarbonate is generally amphoteric in nature; however, the aqueous solutions are mildly alkaline due to the formation of carbonic acid and hydroxide ion:

{HCO}_{3}^{-} + {H}_{2}{O} → {H}_{2}{CO}_{3} + {OH}^{-}

The amphoteric nature of sodium bicarbonate allows it to react with both acids and bases. For instance, you might have witnessed the volcano model somewhere during your schooling. The common ingredients for that model are sodium bicarbonate (baking soda) and vinegar (acetic acid). When they react in a closed environment inside that model, the canon dioxide released in the reaction becomes trapped and erupts from the mouth of the volcano, demonstrating a volcanic eruption. The compounds inside the bottle react as follow:

{NaHCO}_{3}^{-} + {CH}_{3}{COOH} → {CH}_{3}{COONa} + {H}_{2}{O} + {CO}_{2}

Moreover, one must not confuse baking soda with baking powder. While both the compounds may look similar, baking powder is a mixture of baking soda, cream of tartar (a dry acid), and sometimes cornstarch.

5. Washing Soda

Washing soda is an essential chemical compound found in laundry detergent powders and liquids. It is used to remove stubborn stains from laundry. The chemical name for washing soda is sodium carbonate decahydrate, {Na}_{2}{CO}_{3}{.10}{H}_{2}{O}. It is the most common hydrate of sodium carbonate containing 10 molecules of water of crystallization. Sodium carbonate ( {Na}_{2}{CO}_{3} ) is a salt composed of two sodium ions ({2Na}^{+}) and one carbonate ion ({CO}_{3}^{2-}). When dissolved in water, carbonate ions successfully removes the protons from the water and form hydroxide ions and bicarbonate ions. This increases the overall ({OH}^{-}) ions, which in turn increases the pH and makes it more alkaline.

{CO}_{3}^{2-} + {H}_{2}{O} → {HCO}_{3}^{-} + {OH}^{-}

On a commercial scale, sodium carbonate is produced mainly by three processes: Leblanc Process, Solvay’s Process, and Hou’s Process. However, it can also be prepared in the laboratory from a similar salt, sodium bicarbonate.

{NaHCO}_{3}^{-} + {NaOH} → {Na}_{2}{CO}_{3} + {H}_{2}{O}

Apart from acting as a detergent, washing soda helps in cleaning cloths by softening the hard water. Hard water contains dissolved compounds, usually calcium or magnesium compounds. Sodium carbonate is used for removing the temporary and permanent hardness of the water. Since sodium carbonate is water-soluble and magnesium carbonate and calcium carbonate are insoluble, the removal of Mg2+ and Ca2+ is done by treating them with carbonate ions, to form insoluble solid precipitates:

{Ca}^{2+}(aq) + {Na}_{2}{CO}_{3}(aq) → {CaCO}_{3} + 2{Na}^{+}

{Mg}^{2+}(aq) + {Na}_{2}{CO}_{3}(aq) → {MgCO}_{3}(aq) + 2{Na}^{+}

6. Household Bleach

Bleach is a name given to all the compounds that are used for cleaning stains and/or removing color from fabric. It often refers, specifically, to a dilute solution of sodium hypochlorite, also called “liquid bleach.” Sodium hypochlorite (NaOCl), also known as hypochlorous acid, is a salt comprising a sodium cation ({Na}^{+}) and a hypochlorite anion ({OCl}^{-}). Anhydrous sodium hypochlorite is unstable and decomposes explosively. Therefore, it is hydrated with 5 molecules of water of crystallization to form {NaOCl}{.5H}_{2}{O}, which is a non-explosive pale greenish-yellow solid. At room temperature, sodium hypochlorite is more stable in dilute solutions that contain solvated {Na}^{+} and {OCl}^{-} ions. If sodium hypochlorite is not properly stored in airtight containers, it may react with carbon dioxide to form sodium carbonate.

2{NaOCl} + {CO}_{2} + {H}_{2}{O} → {Na}_{2}{CO}_{3} + 2{HOCl}

However, household bleach contains only 3–8% of sodium hypochlorite, by weight, along with 0.01–0.05% sodium hydroxide. The purpose of adding sodium hydroxide is to slow the decomposition of sodium hypochlorite into sodium chloride and sodium chlorate.

7. Preservative 

To keep up with the pace of the ever-developing world, people rely more and more on packaged foods and drinks. Nevertheless, there is always some concern about the contamination of packed food due to the growth of microorganisms such as yeast and bacteria. Thankfully, preservation techniques have come a long way in the past few years, allowing manufacturers and companies to increase the shelf life of their products and significantly lower the risk of food-borne illness. Sodium benzoate ({C}_{6}{H}_{5}{COONa}) is one such preservative that prevents the growth of microorganisms such as bacteria and fungi, and slow the oxidation of fats that cause rancidity. It is denoted by the E number E211 on the food products.

Whenever sodium benzoate dissolves in water, it dissociates into sodium cation {Na}^{+} and benzoate anion {C}_{6}{H}_{5}{COO}^{-}. Another example of a preservative is sodium sulfite {Na}_{2}{SO}_{3}. This is an inorganic compound that comprises of two sodium ions ({2Na}^{+}) and one sulphite ion ({SO}_{3}^{2-}). It is denoted by the E number E221 on the food products. As a reducing agent, it is used as a preservative to prevent dried fruit from discoloring.

8. Anti-caking Agent

When we talk about powdered food materials, such as flour, sugar, dried milk, dried vegetables, dried fruits, bakery mixes, soup powders, spice mixes, juice powders, etc., the common challenge encountered with them during the rainy or humid weather conditions is the formation of lumps. This process in technical terms is known as caking. It is a consequence of the chemical reactions of grain surfaces. Often these reactions involve adsorption of water vapor or other gases. This issue is addressed by placing anticaking additives in the food products. The mechanism involves absorbing excess moisture or coating particles and making them water-repellent. One such anti-caking agent that can be found in table salt is magnesium carbonate, {MgCO}_{3}. It is an inorganic salt that is a white solid that comprises of two magnesium ions ({2Mg}^{+}) and one carbonate ion ({CO}_{3}^{2-}). Because of its low solubility in water and hygroscopic properties, {MgCO}_{3} was first added to salt in 1911 to make it flow more freely by Morton Salt company.

9. Ingredients in Antacids

Most of us enjoy spicy food every now and then. In order to digest that food, sometimes our gastric glands secrete excess acid, and we experience acidity. An antacid is considered one of the most effective remedies for treating heartburn discomfort caused by that extra acid. These compounds are easily available in the market, and they are known to provide instant relief by neutralizing the acid in your stomach. Most of the antacids that are available over the counter consist of several ionic compounds, such as magnesium carbonate, magnesium trisilicate, calcium carbonate, and sodium bicarbonate.