Group 13 elements, also known as the boron group, are a set of elements located in Group 13 of the periodic table. This group consists of boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium (Tl).
These elements share some similarities in their chemical properties but also exhibit distinct characteristics.
Group 13 Elements
Boron (B)
Boron is a metalloid and the lightest element in Group 13. It has an atomic number of 5, which is relatively low. Boron is well-known for its high melting point and remarkable hardness.
Aluminum (Al)
Aluminum is the third most plentiful element in the Earth’s crust and the most abundant metallic element. It has a high strength-to-weight ratio, is corrosion resistant, and has strong electrical conductivity.
Gallium (Ga)
Gallium is a silvery, soft metal with a low melting point. When melted, it has the unusual virtue of having a low viscosity, allowing it to moisten glass or ceramics.
Indium (In)
Indium is a soft, silvery metal found in tiny quantities in the Earth’s crust. Its propensity to create alloys with other metals makes it valuable in a variety of applications.
Thallium (Tl)
Thallium is a dense, bluish-gray metal that is highly toxic and should be handled with extreme caution.
Significance of the Chemistry of Boron Group
1. Industrial Applications: Group 13 elements are widely used in a variety of industrial applications. Because of its low density, corrosion resistance, and electrical conductivity, aluminum is a commonly utilized metal. Understanding the chemistry of aluminum and its alloys aids in the creation of sophisticated materials for sectors including as aerospace, automotive, construction, and packaging.
Similarly, gallium and indium are essential in the manufacture of semiconductors and electrical devices such as lasers, solar cells, and flat-panel displays.
2. Material Science and Engineering: Boron is important in the development of heat-resistant materials such as borosilicate glass and fiberglass due to its excellent hardness and high melting point. Gallium’s low melting point and ability to wet glass allow it to be used to create novel materials and coatings. Researchers can discover new ways to modify these elements’ characteristics and build fresh materials with greater performance by researching their chemistry.
3. Indium tin oxide (ITO), a compound comprised of indium and tin, is extensively utilized as a transparent conductive coating in solar panels and touch displays. Boron compounds are used as fertilizers in agriculture to boost crop growth and yield. Boron chemistry research aids in the development of sustainable agriculture methods and the improvement of food production.
4. Boron is used in boron neutron capture therapy (BNCT), a targeted cancer treatment that takes use of boron-10’s capacity to trap neutrons and unleash high-energy particles within tumor cells. Gallium compounds have been studied for their antibacterial characteristics and possible application in the fight against antibiotic-resistant bacteria. Understanding Group 13 elements’ chemical characteristics and interactions in biological systems can lead to the creation of novel medicines, diagnostic tools, and biomaterials.
5. Research: Group 13 chemistry is an active topic of basic research. Scientists continue to study these elements’ electrical structure, bonding, reactivity, and physical characteristics in order to better comprehend chemical principles and theories. Group 13 chemistry knowledge adds to the larger discipline of inorganic chemistry and gives insights into periodic patterns and element behavior.
Related Post: Noble Gases / Group 18 Chemistry
Natural Occurrence of Group 13 Elements
Group 13 elements have varying degrees of natural occurrence in the Earth’s crust.
Boron is a scarce element in the Earth’s crust when compared to other elements. Its abundance is roughly 10 parts per million (ppm). Boron is generally found in the combined state as borates such as borax and colemanite, which are particularly concentrated in dry locations. Borates are formed by the erosion of boron-containing rocks and are frequently found in evaporite deposits or hydrothermal systems.
Aluminum, the most abundant metal and third most abundant element in the Earth’s crust, accounts for around 8% of its mass and is found mostly in mixed form as bauxite, an aluminum-rich mineral. Bauxite deposits are common in tropical and subtropical climates. The greatest reserves may be found in Australia, Guinea, Brazil, and Jamaica. Aluminum is also present in a variety of silicate minerals, clays, and rocks.
Gallium is a relatively uncommon element in the Earth’s crust, and it is frequently found as a trace element in some aluminum and zinc ores. Gallium may be recovered as a byproduct of bauxite, zinc, and copper ore processing. China, Germany, Ukraine, and Kazakhstan are also significant gallium producers.
Indium is also found as a trace element in the Earth’s crust, particularly in zinc, lead, and tin ores. During the extraction and refining of these metals, indium is frequently produced as a byproduct. The biggest indium reserves are related with zinc resources, with significant production happening in China, South Korea, Canada, and Japan.
Thallium can be found in small amounts in a range of minerals, including copper, lead, and zinc sulfide ores. Thallium may also be found on the ocean floor in manganese nodules and iron-manganese crusts.
Thallium, on the other hand, is not regularly mined or extracted due to its toxicity and little commercial value.
Extraction of Group 13 Elements
Group 13 elements are extracted from the Earth’s crust using specific methods and reactions.
Boron (B)
Boron is primarily extracted by the mining and processing of borate minerals such as borax and colemanite. These minerals are mostly made up of borates, which are then processed into boron compounds for commercial application. The extraction procedure normally consists of the following steps:
Borate ores are mined and crushed to a reasonable size for further processing.
The crushed ore is subsequently acid leached using sulfuric acid (H2SO4) or hydrochloric acid (HCl), which results in the creation of soluble borate salts.
B2O3 + 3H2SO4 → 2H3BO3 + 3SO2 + 3H2O
Purification and Crystallization: The leachate is purified and crystallized to yield pure boron compounds, which are generally in the form of boric acid. (H3BO3).
Aluminum (Al)
Aluminum is primarily extracted from bauxite, an aluminum-rich ore.
Mined bauxite ores are crushed to a sufficient size for further processing.
In the Bayer process, crushed bauxite is combined with a concentrated solution of sodium hydroxide (NaOH) and heated under pressure.
Al2O3 + 2NaOH + 3H2O → 2NaAl(OH)4
The resultant solution is filtered to eliminate contaminants before precipitating aluminum hydroxide (Al(OH)3) by changing the pH.
2NaAl(OH)4 → 2Al(OH)3 + 2NaOH + H2O
Aluminum oxide (alumina) is produced by calcining precipitated aluminum hydroxide at high temperatures. It entails heating the aluminum hydroxide to high temperatures, often about 1000°C, in order to drive off the water molecules and convert it to aluminum oxide, also known as alumina. (Al2O3).
2Al(OH)3 → Al2O3 + 3H2O
The calcined alumina is utilized as feedstock for the Hall-Héroult process, which is used to extract metallic aluminum. Alumina is dissolved in molten cryolite (Na3AlF6) and deposited in an electrolytic cell in this electrolytic process. In the cell, carbon anodes and a graphite cathode are utilized, and a direct electric current is carried through the system.
Cathodic Equation: Al3+ + 3e– → Al (reduction)
Anode Equation: 2O2- → O2 + 4e– (oxidation)
Aluminum ions gain electrons and deposit as molten aluminum metal at the bottom of the cell as a result of the reduction process at the cathode. Meanwhile, alumina oxygen ions travel to the carbon anode and combine to generate gaseous oxygen molecules.
The Hall-Héroult method enables large-scale aluminum production by leveraging an ample supply of alumina obtained from bauxite. This electrolytic extraction process is critical in addressing the world’s demand for aluminum, which is widely employed in a variety of sectors due to its advantageous qualities such as lightweight, high strength, and corrosion resistance.
Gallium (Ga)
Gallium-containing primary ores, such as bauxite or zinc ores, are mined and processed to recover the main metals.
Gallium is extracted and refined from residues or intermediate products produced during primary metal extraction using processes such as solvent extraction, precipitation, or electrolysis.
Indium (In)
Indium is typically extracted as a byproduct during the extraction and refining of zinc, lead, and tin ores.
Primary ores containing zinc, lead, or tin are mined and processed to get the corresponding metals.
Indium is isolated and refined from the residues or byproducts produced during the extraction of primary metals. To collect indium from these sources, several procedures such as solvent extraction and electrolysis are applied.
Thallium (Tl)
Thallium is often derived as a byproduct of the processing of certain sulfide ores, such as copper, lead, and zinc ores.
Primary ores containing copper, lead, or zinc are mined and processed to extract the metals. These sulfide ores may contain trace quantities of thallium.
Sulfide ores are often treated to a succession of crushing, grinding, and froth flotation procedures in order to concentrate the required metal sulfides and separate them from the gangue minerals.
Smelting is performed on the concentrated sulfide ore, which contains copper, lead, zinc, and trace quantities of thallium. In this process, the ore is burned in a furnace with a reducing agent, such as coke or carbon, to eliminate the sulfur and transform the metal sulfides into metallic forms.
MS (metal sulfide) + C (carbon) → M (metal) + CS2 (carbon disulfide)
As a trace element, thallium becomes concentrated in smelter flue gases, slags, or other byproducts during the smelting process. To separate and recover thallium from these byproducts, several procedures such as precipitation, solvent extraction, or electrolysis are used.
This is a Quiz for the Chemistry of Group 13 Elements
Electronic Configuration and Oxidation Numbers
| Element | Atomic Number | Mass Number | Electronic Configuration | Oxidation Numbers |
|---|---|---|---|---|
| Boron (B) | 5 | 10.81 | 1s2 2s2 2p1 | +3 |
| Aluminum (Al) | 13 | 26.98 | 1s2 2s2 2p6 3s2 3p1 | +3 |
| Gallium (Ga) | 31 | 69.72 | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p1 | +3 |
| Indium (In) | 49 | 114.82 | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p1 | +1, +3 |
| Thallium (Tl) | 81 | 204.38 | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p1 | +1, +3 |
Electronic Configuration and Chemical Properties
Like every other element, the electronic arrangement of each atom in Group 13 is strongly connected to its chemical characteristics. Valence electrons, in particular, play an important role in shaping chemical behavior. Here are some major links between electron configuration and Group 13 element chemical properties:
1. Elements in Group 13 have three valence electrons in their outermost energy level. These elements’ valence electron configuration is ns2np1, where “n” indicates the energy level Period. Group 13 is represented by the three superscripts on s and p. These elements have comparable chemical properties due to the presence of one valence electron in the p orbital.
2. Electronegativity levels for Group 13 elements are typically low. They have a tendency to shed their valence electron in order to acquire a stable electron configuration and a positive oxidation state. This phenomenon is explained by the valence electron’s comparatively larger atomic size and the low effective nuclear charge.
3. Group 13 elements generally have oxidation states of +3 due to the loss of their three valence electrons. This enables them to create a stable noble gas electron configuration. However, boron, due to its smaller size and higher ionization energy, can also have an oxidation state of +1.
4. The elements of Group 13 are distinguished by their mild reactivity. They react with nonmetals to generate ionic compounds in which they give valence electrons to electronegative atoms. Because of the lowering ionization energy and rising atomic size as you proceed down the group, the reactivity rises.
5. Lewis acidity is shown by Group 13 elements, notably aluminum, gallium, and indium. This implies they can receive a pair of electrons in order to establish coordinate covalent connections. This feature is linked to the electron configuration’s imperfect valence, which allows them to receive an electron pair from a Lewis base.
Factors Affecting Stability of Oxidation States in Group 13 Elements
1. Atomic size is an important factor in affecting the stability of oxidation states in Group 13 elements. The atomic size grows as we travel along the group. Boron (B), for example, being the smallest element in the group, prefers the +3-oxidation state due to its tiny atomic size and high ionization energy.
– Thallium (Tl), the group’s biggest element, is more likely to display the +1-oxidation state due to its larger atomic size and lower ionization energy.
2. Ionization energy is the amount of energy necessary to remove an electron from an atom’s valence shell. It influences the stability of various oxidation states in Group 13 elements. As an example:
– Aluminum (Al) and gallium (Ga) have relatively low ionization energies, making it simpler for them to lose electrons and display the +3-oxidation state as their preferred state.
– Thallium (Tl) has a lower ionization energy than the other elements in the group, allowing it to shed its valence electron more easily and display the +1-oxidation state.
3. The propensity of an atom to attract electrons determines the stability of oxidation states in Group 13 elements. Boron (B), for example, has a comparatively high electronegativity compared to the other elements in the group. This strong electronegativity adds to its predilection for the +3-oxidation state, since it prefers to receive electrons rather than give them.
– Thallium (Tl) has the lowest electronegativity in the group, which promotes its tendency to lose electrons and display the +1-oxidation state.
4. The stability of electron configurations inside distinct subshells might affect oxidation state stability. For example, aluminum (Al) and gallium (Ga) display the +3-oxidation state preferentially because the stability of the completely filled 3p subshell favors the loss of three valence electrons.
– Because of the stability of distinct subshells, indium (In) and thallium (Tl) tend to display a diversity of oxidation states. Indium, for example, can have +3 and +1 oxidation states, whereas thallium can have +3 and +1 oxidation states, with relativistic effects altering the stability of distinct subshells.
5. Coordination chemistry, in which elements form complexes with ligands, can also impact the stability of different oxidation states. This is especially true for aluminum (Al) and gallium (Ga), which can display a variety of oxidation states in coordination complexes depending on the ligands involved.
Inert Pair Effect
The inert pair effect is found in Group 13 elements, notably the heavier elements (gallium, indium, and thallium). Despite their propensity to display higher oxidation states, these elements prefer to stabilize lower oxidation states, notably the +1-oxidation state.
The growing energy differential between the ns and (n-1)d orbitals as the atomic number grows influences the inert pair effect in Group 13 elements. Because of this disparity, the ns electrons are less accessible for bonding, resulting in a preference for lower oxidation states.
1. Boron has no major inert pair impact because it prefers the +3 oxidation state, where it loses three valence electrons. Because of its tiny atomic size and high ionization energy, it is less prone to display lower oxidation states.
2. Aluminum has a little inert pair effect. It is mostly in the +3 oxidation state, having lost three valence electrons. Aluminum’s low ionization energy and atomic size contribute to its stability in the +3 oxidation state rather than the +1 oxidation state.
3. Gallium (Ga): Gallium has a significant inert pair effect. While its anticipated valence electron oxidation state is +3, it can alternatively display the +1 oxidation state. Gallium’s greater atomic size and lower ionization energy allow its 4s and 4p electrons to engage in bonding and maintain the +1 oxidation state, resulting in the inert pair effect.
4. Indium (In): Indium has a strong inert pair effect. It has the ability to display both +3 and +1 oxidation states. Because of indium’s greater atomic size and lower ionization energy, the 5s and 5p electrons are more likely to engage in bonding and sustain the +1 oxidation state.
5. Thallium (Tl): Thallium has the strongest inert pair effect of any Group 13 element. Despite possessing a valence electron structure that suggests a +3 oxidation state, thallium is more likely to display a +1 oxidation state. Because of thallium’s greater atomic size and lower ionization energy, the 6s and 6p electrons are less accessible for bonding, resulting in the stability of the +1 oxidation state.
Understanding the inert pair effect is critical for forecasting the chemical behavior and reactivity of the heavier Group 13 elements, especially gallium, indium, and thallium, which can have both +3 and +1 oxidation states.
Diagonal Relationship Between Al and Be
Atomic Size
Aluminum and beryllium have tiny atomic sizes in comparison to other elements in their families. This atomic size closeness allows for comparable bonding and chemical action.
Electronegativity
The electronegativity ratings of aluminum and beryllium are quite low. Because of their commonality, they are both prone to the formation of predominantly covalent compounds.
Oxidation States
Beryllium normally has a +2-oxidation state, whereas aluminum has a +3 oxidation state. Under some conditions, however, aluminum can display a +1-oxidation state.
Compound Formation
Aluminum: Aluminum easily forms compounds with a wide range of elements. Aluminum oxide (Al2O3) is a noteworthy chemical that forms a protective coating on the surface of aluminum and offers corrosion resistance.
4 Al + 3O2 -> 2Al2O3
Aluminum also reacts with acids to generate a variety of salts. The reaction between aluminum and hydrochloric acid (HCl), for example, can be described as:
2 Al + 6HCl -> 2AlCl3 + 3 H2
Beryllium produces covalent compounds due to its low electronegativity. One example is beryllium chloride (BeCl2), which may be produced by the interaction of beryllium with chlorine:
Be + Cl2 -> BeCl2
While aluminum and beryllium have certain similarities owing to their diagonal connection, there are also significant variances. As an example:
Aluminum has a higher reactivity than beryllium. Beryllium does not readily react with oxygen to generate aluminum oxide, but aluminum does.
– Beryllium compounds, such as beryllium chloride (BeCl2), have a higher ionic character than aluminum compounds. This is owing to the beryllium ion’s increased charge density and smaller size.
– Beryllium creates covalent hydrides such as beryllium hydride (BeH2), but aluminum does not.
Physical Properties of Group 13 Elements
| Element | Atomic Mass | Melting Point (°C) | Boiling Point (°C) | Density (g/cm³) | Allotropes | Appearance |
|---|---|---|---|---|---|---|
| Boron | 10.81 | 2076 | 3927 | 2.34 | Amorphous, crystalline | Black (amorphous), brownish-black (crystalline) |
| Aluminum | 26.98 | 660 | 2467 | 2.7 | None | Silvery-white |
| Gallium | 69.72 | 29.76 | 2403 | 5.91 | None | Silvery-white |
| Indium | 114.82 | 156.6 | 2072 | 7.31 | None | Silvery-white |
| Thallium | 204.38 | 304 | 1473 | 11.85 | None | Silvery-white |
Related Post: Exploring Classes of Chemical Reactions
Allotropes of Group 13 Elements
Group 13 elements do not typically exhibit allotropy.
The occurrence of many forms or structures of an element in the same state of matter is referred to as allotropy.
It is crucial to note, however, that boron (B) may vary in structure and bonding patterns, resulting in distinct forms known as allotropes.
1. Amorphous Boron: Amorphous boron lacks a distinct crystal lattice structure. It’s often a brownish-black powder made up of tiny, unevenly organized boron particles. Amorphous boron is utilized in a variety of applications, including pyrotechnics, rocket propellants, and the manufacture of boron fibers.
2. Crystalline Boron: Boron atoms are arranged in well-ordered, repeating patterns in crystalline boron. It may occur in a variety of crystal forms, such as -rhombohedral, -rhombohedral, and -tetragonal boron. These crystalline boron forms have diverse boron atom configurations and exhibit varied physical characteristics. Crystalline boron appears grayish-black or metallic.
Chemical Properties of Group 13 Elements
Group 13 elements exhibit a general trend of increasing reactivity as you move down the group.
1. Boron (B) is the least reactive element in Group 13. Because of its tiny size and strong electronegativity, it features a peculiar electron-deficient structure.
• Boron forms strong covalent bonds and may behave as both a metalloid and a nonmetal at ambient temperature.
• However, it combines with strong oxidizing chemicals, such as fluorine, to generate boron trifluoride (BF3).
• Boron compounds, often known as borates, are used in a variety of applications, including glass manufacture, detergents, and as organic chemistry catalysts.
2. Aluminum (Al) is a highly reactive metal with higher reactivity than boron.
Al rapidly interacts with oxygen in the air to generate a thin, transparent oxide coating that is resistant to corrosion. The metal is protected from further oxidation by this passive oxide layer. This is known as passivation.
Aluminum may also react with strong acids like hydrochloric acid or sulfuric acid to form aluminum salts and hydrogen gas. These are exothermic processes that occur when heat develops.
Reaction with Hydrochloric Acid:
2 Al + 6 HCl → 2 AlCl3 + 3 H2
Reaction with Sulfuric Acid:
2 Al + 3 H2SO4 → Al2(SO4)3 + 3 H2
It is, however, resistant to most mild acids.
Aluminum’s reactivity, availability, and low density make it useful in a variety of sectors, including building, transportation, and packaging.
Aluminum conducts a base-metal displacement reaction when it interacts with a basic, such as sodium hydroxide (NaOH).
2 Al + 2 NaOH + 6 H2O → 2 Na[Al(OH)4] + 3 H2
Aluminum (Al) combines with sodium hydroxide (NaOH) in the presence of water (H2O) to create sodium tetrahydroxoaluminate (Na[Al(OH)4] and hydrogen gas (H2) in this reaction.
The aluminum hydroxide complex, Na[Al(OH)4], is formed as a result of the displacement of sodium from sodium hydroxide by aluminum. As a byproduct of the exothermic process, hydrogen gas is produced. The formed aluminum hydroxide complex is water soluble and forms a solution.
3. Gallium (Ga) is a soft, silvery metal with lesser reactivity than aluminum.
• It is largely unreactive in dry air and does not readily react with water or most acids, although it does react with strong bases and some acids, such as nitric acid, to generate gallium salts.
1. Reaction with Strong Bases:
Ga + 2 NaOH + 2 H2O → 2 Na[Ga(OH)4] + H2
In the presence of water (H2O), gallium (Ga) combines with a strong base, such as sodium hydroxide (NaOH), to create sodium tetrahydroxogallate (Na[Ga(OH)4] and hydrogen gas (H2). Gallium atoms are oxidized and mix with hydroxide ions to create the gallate complex.
2. Reaction with Nitric Acid:
2 Ga + 10 HNO3 → 2 Ga(NO3)3 + 5 H2O + N2O
Gallium nitrate (Ga(NO3)3), water (H2O), and nitrogen dioxide gas (NO2) are formed when gallium interacts with nitric acid (HNO3). This reaction happens when gallium is oxidized and nitric acid is reduced to nitrogen dioxide.
• It may also combine with nonmetals to generate compounds like gallium arsenide (GaAs) and gallium nitride (GaN), both of which have key applications in semiconductors, LEDs, and solar cells. Gallium’s peculiar melting point near room temperature makes it useful in high-temperature thermometers and heat transmission devices.
4. Indium (In) is a soft, silvery metal with the same reactivity as gallium. In dry air, it is largely unreactive, but when exposed to moist air, it progressively oxidizes. Indium combines with nonmetals such as halogens to generate compounds such as indium trichloride (InCl3) and indium oxide (In2O3). It may also react with acids to form indium salts like indium sulfate (In2(SO4)3) and indium nitrate (In(NO3)3).
5. Thallium (Tl) is the most reactive element in Group 13. It easily reacts with halogens like chlorine and bromine to generate thallium halides. Thallium may also react with oxygen, sulfur, and certain acids. It is extremely poisonous and should be handled with extreme caution. Thallium’s reactivity and toxicity limit its usage, however it is used in speciality glass and high-temperature superconductors.
Amphoteric Properties of Group 13 Elements
Amphoteric substances have the ability to act as both acids and bases, depending on the reaction conditions.
| Element | Amphoteric Behavior | Chemical Equation |
|---|---|---|
| Boron (B) | Weakly amphoteric | 2 B + 3 H2O + 6 HCl → 2 BCl3 + 3 H2 |
| Aluminum (Al) | Highly amphoteric | 2 Al + 2 NaOH + 6 H2O → 2 Na[Al(OH)4] + 3 H2 |
| Gallium (Ga) | Amphoteric | 2 Ga + 10 HNO3 → 2 Ga(NO3)3 + 5 H2O + N2O |
| Indium (In) | Amphoteric | 2 In + 6 HCl → 2 InCl3 + 3 H2 |
| Thallium (Tl) | Limited amphoteric behavior | TlOH + 2 HNO3 → TlNO3 + H2O |
Lewis Acidity and Coordination Chemistry of Group 13 Elements
Group 13 elements display Lewis acidity and participate in coordination chemistry.
Lewis Acidity
Lewis acids are electron-deficient elements that have a tendency to receive electron pairs. The Lewis acidity increases along the group due to the elements’ increasing size and decreasing electronegativity. Here are several Lewis acidity examples in Group 13 elements:
Boron (B): Boron trifluoride (BF3) is a famous example of Lewis acidity in boron. It performs the function of a Lewis acid by receiving an electron pair from a Lewis base, such as ammonia (NH3):
BF3 + NH3 → F3B:NH3
– Aluminum (Al): Aluminum chloride (AlCl3) is a Lewis acid that has received a lot of attention. It receives electron pairs from Lewis bases, as evidenced by the chlorine reaction (Cl2):
AlCl3 + Cl2 → AlCl4– + Cl–
– Gallium (Ga): Gallium trichloride (GaCl3) is another Lewis acid that can react with Lewis bases. For instance, it reacts with water (H2O) to form gallium hydroxide (Ga(OH)3):
GaCl3 + 3 H2O → Ga(OH)3 + 3 HCl
– Indium (In): Indium trichloride (InCl3) exhibits Lewis acidity and reacts with Lewis bases. It reacts with sodium iodide (NaI) to form indium(III) iodide (InI3):
InCl3 + 3 NaI → InI3 + 3 NaCl
– Thallium (Tl): Thallium(I) chloride (TlCl) demonstrates limited Lewis acidity compared to other Group 13 elements. It can react with Lewis bases such as ammonia (NH3) to form adducts:
TlCl + NH3 → TlCl(NH3)
Coordination Chemistry
Group 13 elements generate coordination complexes by accepting electron pairs from ligands, which results in the creation of coordinate covalent bonds.
– Aluminum (Al): Aluminum forms various coordination complexes. One example is the reaction between aluminum chloride (AlCl3) and dimethyl ether (CH3)2O to form a coordination complex:
AlCl3 + 2 (CH3)2O → Al(OCH3)2Cl + HCl
– Gallium (Ga): Gallium can form coordination compounds with ligands such as amines. An example is the reaction between gallium(III) chloride (GaCl3) and ethylenediamine (en):
GaCl3 + 3 H2NCH2CH2NH2 → [Ga(en)3]Cl3
– Indium (In): Indium forms coordination complexes with various ligands. For instance, the reaction between indium(III) chloride (InCl3) and ethylenediamine (en) yields a coordination complex:
InCl3 + 3 H2NCH2CH2NH2 → [In(en)3]Cl3
Anomalous Behaviour of Group 13 Elements
The Group 13 elements exhibit some intriguing and anomalous behaviors compared to other elements in the periodic table.
1. Electronic Configuration: The Group 13 elements have three valence electrons in their outermost shell, which corresponds to the typical electrical configuration ns2np1. Boron, on the other hand, deviates from this pattern since it only contains two valence electrons (2s22p1). Boron is an uncommon element with unique chemical characteristics due to its electron shortage.
2. Metallicity: Aluminum is a typical metal, while boron is a metalloid and gallium, indium, and thallium are post-transition metals. This transformation from a nonmetal to a metal across the group is fascinating. Boron shows several nonmetallic features, including as brittleness and strong reactivity, due to its short atomic size and electron deficit.
3. Oxidation States: Because of their proclivity to shed three valence electrons and acquire a stable noble gas structure, Group 13 elements often have an oxidation state of +3. Gallium and indium, on the other hand, can have +1 oxidation states, especially in specific combinations. This capacity to exhibit numerous oxidation states is uncommon for these elements.
4. Anomalous Size: Atomic and ionic radii often increase down the boron group. When comparing gallium with aluminum, there is one exception. Despite being positioned below aluminum in the periodic table, gallium has a greater atomic radius than aluminum. This can be linked to the existence of inner d-electrons in gallium, which encounter poor shielding and result in a higher atomic radius.
5. Ga-In Eutectic Point: Gallium and indium exhibit unusual eutectic characteristics. The lowest melting point of a combination of two or more elements is known as a eutectic point. When gallium (29.8°C melting point) and indium (156.6°C melting point) combine, a eutectic combination with a melting point as low as -19°C is formed. Because of the low melting point, the combination may exist as a liquid at normal temperature, which opens up new possibilities for thermometers, coolants, and low-temperature experiments.
6. Thallium’s Toxicity: Thallium stands out among the Group 13 elements due to its high toxicity. It is extremely dangerous and can cause significant health problems, including harm to the neurological system, digestive system, and different organs. Thallium compounds used to be included in rat poisons and insecticides, but their use has been severely restricted due to their toxicity.
Compounds of Group 13 Elements and Their Properties
Group 13 elements form a variety of compounds with distinct properties. Some are binary while others are ternary compounds.
Boron Compounds
– Boron Trihalides (BX3): Boron trifluoride (BF3), boron trichloride (BCl3), and boron tribromide (BBr3) are all trihalides. These are highly reactive Lewis acids that can receive electron pairs from Lewis bases.
– Boron Oxides (B2O3): Boron oxide is an amorphous solid formed by the reaction of boron with oxygen. It has a high melting point and is used in glassmaking as a flux.
Borates: Boron compounds, such as sodium borate (Na2B4O7) and borax, can create borate salts. Borates are used in a variety of industries, including cleaning agents and flame retardants.
Aluminum Compounds
– Aluminum Oxide (Al2O3): Aluminum oxide, often known as alumina, is a white powder with a high melting point. It is frequently used in ceramics manufacture, as an abrasive, and as a catalyst.
– Aluminum Chloride (AlCl3): As a Lewis acid, aluminum chloride is often utilized as a catalyst in organic synthesis processes. It can also produce Lewis base adducts.
– Aluminum Hydroxide (Al(OH)3): Aluminum hydroxide is an amphoteric chemical that may function as a base as well as an acid. It is found in antacids as well as vaccinations.
Gallium Compounds
– Gallium Nitride (GaN) is a semiconductor material that has several uses in optoelectronics and high-power devices.
– Gallium Arsenide (GaAs): Another major semiconductor utilized in electrical devices such as high-frequency amplifiers and solar cells is gallium arsenide.
Indium Compounds
– ITO (Indium Tin Oxide): ITO is a transparent conductive oxide that is commonly utilized in electronic displays and touchscreens.
– Indium Halides: Indium may be converted into halides such as indium chloride (InCl3) and indium iodide (InI3). These chemicals are used in organic synthesis and as catalysts.
Thallium Compounds
– Thallium(I) Sulfate (Tl2SO4): Thallium(I) sulfate is a white crystalline compound used in the synthesis of other thallium compounds.
– Thallium(I) Acetate (TlCH3COO): Thallium(I) acetate is a chemical compound used in organic reactions and as a mordant in textile dyeing.
Some Binary Compounds of Group 13 Elements
| Compound | Chemical Formula | Properties |
|---|---|---|
| Boron Trifluoride | BF3 | Colorless gas, highly reactive, Lewis acid |
| Aluminum Oxide | Al2O3 | White solid, high melting point, used in ceramics |
| Gallium Arsenide | GaAs | Semiconductor, used in electronic devices |
| Indium Chloride | InCl3 | White solid, used in organic synthesis |
| Thallium(I) Sulfate | Tl2SO4 | White solid, used in chemical synthesis |
The chemistry of the Boron family, which includes elements such as boron, aluminum, gallium, indium, and thallium, is extremely important in many scientific fields. These elements contribute to scientific discoveries by their unique bonding behavior and numerous uses. Boron’s bonding flexibility is used in laundry detergents and fire retardants. Aluminum’s strength and resistance to corrosion make it excellent for airplanes and daily items. Alloys, semiconductors, and transparent conductors all need gallium, indium, and thallium. In conclusion, the chemistry of the Boron family is important in science and has a wide range of practical applications.
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