Chuong 3-Halogens

GROUP VIIA
The Halogens
Halogens (Greek hals, “salt”; genes, “born”)
Tính chất lý học
Tính chất hóa học
Điều chế và ứng dụng
Hidro halogenua
Hợp chất chứa oxi của halogen
Department of Inorganic Chemistry - HUT
Department of Inorganic Chemistry - HUT
Group 17 Elements
Also known as Group VIIA
Halogens
Nonmetals:
Fluorine (F) and Chlorine (Cl) are gases
Bromine (Br) is a liquid
Iodine (I) is a solid
Metalloid:
Astatine (At) is a solid
Department of Inorganic Chemistry - HUT
Department of Inorganic Chemistry - HUT
Department of Inorganic Chemistry - HUT
The Lewis dot structure
X
ns2np4nd1: ClF3
ns2np5
ns2np3nd2: BrF5
ns2np2nd3: IF7
Department of Inorganic Chemistry - HUT
Isotopes
Cl-35 makes up about 75% of chlorine atoms in nature, and Cl-37 makes up the remaining 25%
the average atomic mass of Cl is 35.45 amu
Cl-35 has a mass number = 35, 17 protons and 18 neutrons (35 - 17)
Halogens are fluorine, F; chlorine, Cl; bromine, Br; iodine, I; and astatine, At.
Halogens contain 7 valence electrons.
As elements, halogens are diatomic.
Fluorine is a reactive, pale, yellow gas.
F is used in compounds of carbon to form fluorocarbons.
Teflon is an example of a fluorocarbon.
Other fluorocarbons include the Freons used as refrigerants.
Many fluorocarbons are no longer used because of their effect on the ozone layer.
Chlorine is a reactive green-yellow gas.
Cl2 used to purify water and in the production of paper, textiles, bleaches, medicines, and other consumer products.
Bromine is a red liquid
Br is used in photographic chemicals, dyes, pharmaceuticals, and fire retardants.
Iodine is a crystalline solid.
I2 sublimes, turns directly from a solid to a gas when heated.
Iodine is present in brine fields in oil field in California and Louisiana and in sea plants.
Iodine compounds are used in photographic chemicals and medicines.
Iodine is required by the human body in the thyroid.
All isotopes of astatine are radioactive.
Ionic radii
Cation formation
vacates outermost orbital
and decreases e-e repulsions
SIZE DECREASES
Anion formation
increases e-e repulsions
so they spread out more
SIZE INCREASES
**
GROUP VIIA
The Halogens
Tính chất lý học
Tính chất hóa học
Điều chế và ứng dụng
Hidro halogenua
Hợp chất chứa oxi của halogen
Department of Inorganic Chemistry - HUT
Department of Inorganic Chemistry - HUT
Tính oxi hóa mạnh nhất
Tính khử

X2(k) = 2X(k)
X-X
A
F không có orbital hóa trị d tham gia liên kết
Orbital hóa trị tăng dần các:
Năng lượng
Số lượng tử chính: n
Số nút hàm xuyên tâm: n-l-1
Department of Inorganic Chemistry - HUT
Năng lượng liên kết cộng hóa trị Echt
Độ xen phủ của các orbital hóa trị lớn khi:
Miền xen phủ rộng và mật độ e ở miền xen phủ lớn.
Z’ đối với orbital hóa tị lớn.
Số lượng tử chính n nhỏ.
Hiệu năng lượng các orbital hóa trị trong nguyên tử và giữa các nguyên tử tham gia liên kết là nhỏ.
Số nút hàm xuyên tâm của của orbital hóa trị là ít (số nút = n – l -1).
Ở miền xen phủ có nhiều orbital hóa trị tham gia.

Yếu tố quyết định năng lượng liên kết là bậc liên kết. Khi bậc liên kết bằng nhau nhưng Echt khác nhau là do độ xen phủ các orbital hóa trị là khác nhau.
Trong 1 chu kỳ, từ trái qua phải:
Z’ đối với các orbital hóa trị tăng dần  Echt tăng dần.
Hiệu năng lượng các orbital hóa trị, Enp-Ens, giảm dần  Echt giảm dần
Tổng Echt sẽ là giá trị cạnh tranh giữa 2 xu hướng này.

Trong 1 phân nhóm A, từ trên xuống:
Năng lượng các orbital hóa trị cùng dạng tăng dần.
Số lượng tử chính n của các orbital hóa trị tăng làm số nút hàm xuyên tâm tăng.
 Echt giảm dần.
Department of Inorganic Chemistry - HUT
F2
Năng lượng liên kết F-F nhỏ
Ái lực với electron lớn
Năng lượng liên kết của F với nguyên tố khác lớn
Khả năng hidrat hóa của ion F- lớn
Department of Inorganic Chemistry - HUT
X2
Department of Inorganic Chemistry - HUT
Tính khử
X2
Department of Inorganic Chemistry - HUT
X2
GROUP VIIA
The Halogens
Tính chất lý học
Tính chất hóa học
Điều chế và ứng dụng
Hidro halogenua
Hợp chất chứa oxi của halogen
Department of Inorganic Chemistry - HUT
Department of Inorganic Chemistry - HUT
F2
Fluorine (Latin fluo, “flow”), symbol F, chemically reactive, poisonous gaseous element. The atomic number of fluorine is 9.
Fluorine occurs naturally in the combined form as fluorite-CaF2, cryolite-Na3AlF6, and apatite-Ca5(PO4)3F. Fluorite, from which most fluorine compounds are generally derived, is commonly mined in the United States from large deposits in northern Kentucky and southern Illinois. Fluorine also occurs as fluorides in seawater, rivers, and mineral springs, in the stems of certain grasses, and in the bones and teeth of animals. It is the 17th element in order of abundance in the crust of the earth.
1886
French chemist
Henri Moissan.
Department of Inorganic Chemistry - HUT
CaF2
FLUORITE, "The Most Colorful Mineral in the World"
Department of Inorganic Chemistry - HUT
Na3AlF6
Cryolite, mineral, sodium aluminum fluoride (Na3AlF6). Cryolite has a hardness of 2.5 and a specific gravity of about 3. It crystallizes in the monoclinic system (see Crystal). It is colorless and ranges from transparent to translucent. It has a waxy appearance, making it almost invisible when powdered and suspended in water. Cryolite was found in abundance only at Ivigut, Greenland. However, that deposit has been exhausted since 1987. The mineral is still found in small quantities in Colorado, USA; Sallent, Huesca Province, Spain; Miask, Urals, USSR; and Montreal, Quebec, Canada. It is used chiefly as a solvent of alumina in the electrolytic preparation of aluminum. Because of its scarcity, this mineral has been replaced in industrial processes by artificially produced sodium aluminum fluoride.
Department of Inorganic Chemistry - HUT
Ca5(PO4)F
Apatite (Greek apate, “deception”), mineral so named because it resembles various other minerals for which it might be mistaken. It consists chiefly of phosphate of lime. Apatite is a distinct mineral of composition Ca5(PO4)3F in which some or all of the fluorine may be replaced by chlorine (chlorapatite). The mineral crystallizes in the hexagonal system (see Crystal) and has a hardness of 5 and a specific gravity of 3.2. When pure, apatite is colorless and transparent, but it may exhibit various degrees of color and opacity. These mineral phosphates of lime were often used in the preparation of fertilizers, but they have been replaced by phosphate rock.
Department of Inorganic Chemistry - HUT
The preparation of fluorine as a free element is difficult and seldom done, since free fluorine is very reactive. However, gaseous fluorine can be prepared by electrolytic techniques (KHF2, HF – 100 0C, and liquid fluorine may be prepared by passing the gas through a metal or rubber tube surrounded by liquid air.
F2
Fluorine compounds have many applications. The chlorofluorocarbons, odorless and nonpoisonous liquids or gases such as Freon-CFCl3, are used as a dispersing agent in aerosol sprays and as a refrigerant. In 1974, however, some scientists suggested that these chemicals reached the stratosphere and were destroying the earth`s ozone layer. With confirmation of these findings by the late 1980s, the production of these chemicals began to be phased out (see Environment). Another chemical, Teflon, a fluorine plastic that is very resistant to most chemical action, is widely used to make such products as motor gaskets and dashboard accessories in the automobile industry. Teflon is also used as a coating on the inner surface of frying pans and other kitchen utensils to reduce the need for fat in cooking. Many organic fluorine compounds developed during World War II (1939-1945) showed extensive commercial potential. For example, the liquid fluorinated hydrocarbons derived from petroleum are useful as highly stable lubricating oils. Uranium hexafluoride, the only volatile compound of uranium, is used in the gaseous diffusion process to provide fuel for atomic power plants
Department of Inorganic Chemistry - HUT
Department of Inorganic Chemistry - HUT
Cl2
Chlorine, symbol Cl, greenish-yellow gaseous element. In group 17 (or VIIa) of the periodic table, chlorine is one of the halogens. The atomic number of chlorine is 17.
Elementary chlorine was first isolated in 1774 by the Swedish chemist Carl Wilhelm Scheele, who thought that the gas was a compound; it was not until 1810 that the British chemist Sir Humphry Davy proved that chlorine was an element and gave it its present name.
KMgCl3 - 6H2O, Hydrated Potassium Magnesium Chloride
CARNALLITE
Department of Inorganic Chemistry - HUT
The gas has an irritating odor and in large concentration is dangerous; it was the first substance used as a poison gas in World War I (1914-1919) (see Chemical and Biological Warfare).
KCl, Potassium Chloride
HALITE
NaCl, Sodium Chloride
Department of Inorganic Chemistry - HUT
Most chlorine is produced by the electrolysis of ordinary salt solution, with sodium hydroxide as a by-product. Because the demand for chlorine exceeds that for sodium hydroxide, some industrial chlorine is produced by treating salt with nitrogen oxides or by oxidizing hydrogen chloride. Chlorine is shipped as a liquid in steel bottles or tank cars. It is used for bleaching paper pulp and other organic materials, destroying germ life in water, and preparing bromine, tetraethyl lead, and other important products.
Department of Inorganic Chemistry - HUT
Bromine has been used in the preparation of certain dyes and of dibromoethane (commonly, ethylene bromide), a constituent of antiknock fluid for leaded gasoline. Bromides are used in photographic compounds and in natural gas and oil production.
Br2
I2
Iodine is medicinally very important because it is an essential trace element, present in a hormone of the thyroid gland that is involved in growth-controlling and other metabolic functions. Without iodine, stunted growth and conditions such as goiter can result. Thus in areas where iodine is not sufficiently abundant naturally, iodine-containing salt serves to make up the deficit. In medicine, iodine-alcohol solutions and iodine complexes have been used as antiseptics and disinfectants. Radioisotopes of iodine are used in medical and other fields of research. More broadly, various iodine compounds find use in photography, the making of dyes, and cloud-seeding operations. In chemistry, various iodine compounds serve as strong oxidizing agents, among other uses.
Thyroid Gland, endocrine gland found in almost all vertebrate animals and so called because it is located in front of and on each side of the thyroid cartilage of the larynx. It secretes a hormone that controls metabolism and growth.
Department of Inorganic Chemistry - HUT
At2
Astatine (Greek astatos, “unstable”), symbol At, radioactive element that is the heaviest of the halogens. The atomic number of astatine is 85.

Originally called alabamine because of early research with the element at Alabama Polytechnic Institute, it was prepared in 1940 by bombarding bismuth with high-energy alpha particles. The first isotope synthesized had an atomic weight of 211 and a half-life of 7.2 hours. Subsequently, astatine-210 was produced and found to have a half-life of about 8.3 hours. Isotopes of astatine with mass numbers from 200 to 219 have been cataloged, some with half-lives measured in fractions of a second.

Astatine is the halogen that behaves most like a metal and that has only radioactive isotopes. It is highly carcinogenic: Mammary and pituitary tumors have been induced in laboratory animals by a single injection.
GROUP VIIA
The Halogens
Tính chất lý học
Tính chất hóa học
Điều chế và ứng dụng
Hidro halogenua
Hợp chất chứa oxi của halogen
Department of Inorganic Chemistry - HUT
Department of Inorganic Chemistry - HUT
HX
Department of Inorganic Chemistry - HUT
HF là axít yếu
HCl, HBr, HI là các axit mạnh
Department of Inorganic Chemistry - HUT
Trừ HF, tính khử tăng dần HCl, HBr, HI
Hydrogen Chloride, colorless, corrosive, nonflammable gas, formula HCl, with a characteristic penetrating, suffocating odor. It melts at - 114.22° C, boils at - 85.05° C, and has a density of 1.268 (air = 1.000). Hydrogen chloride dissolves readily in water: 1 vol. of water at 20° C absorbs 442 vol. of hydrogen chloride gas at atmospheric pressure. The resulting solution—hydrochloric acid—contains 40.3 percent hydrogen chloride by mass and has a specific gravity of 1.20. This solution fumes strongly in moist air, but dilution stops the fuming. Hydrogen chloride becomes less soluble in water as the water temperature rises, and it is less soluble in alcohol, ether, and in other organic liquids.

In solution in water, the molecules of hydrogen chloride ionize, becoming positively charged hydrogen ions and negatively charged chloride ions. Because it ionizes easily, hydrochloric acid is a good conductor of electricity. The hydrogen ions give hydrochloric acid its acidic properties, so that all solutions of hydrogen chloride and water have a sour taste; corrode active metals, forming metal chlorides and hydrogen; turn litmus red; neutralize alkalies; and react with salts of weak acids, forming chlorides and the weak acids.

Hydrogen chloride is produced industrially as a by-product of the reaction of chlorine with hydrocarbons to produce organic chlorides. Hydrochloric acid may be made by the reaction of sodium chloride with sulfuric acid or by combining hydrogen and chlorine. Crude industrial hydrochloric acid is called muriatic acid. It is used in large quantities in the preparation of chlorides and for cleaning metals and in industrial processes such as preparation of corn syrup and glucose from cornstarch. Small amounts of hydrochloric acid are secreted by cells in the lining of the stomach to aid in food digestion.

Hydrobromic acid is a solution of hydrogen bromide gas, formula HBr, and water. The gas is colorless, with a penetrating odor, boiling point - 67° C. Hydrobromic acid is formed by the direct union of hydrogen and bromine in the presence of a catalyst, such as platinum; another method is to brominate phosphorus to form phosphorus tribromide, which hydrolyzes in water to form phosphorous acid and hydrobromic acid (see Hydrolysis). Hydrobromic acid, like hydrochloric acid, is a strong acid. It reacts with metals, some salts, and bases to form bromides.

Hydriodic acid is a solution of hydrogen iodide gas and water, with the formula HI. The gas is colorless, with a penetrating odor, boiling point -35° C. Hydriodic acid is formed in the same manner as hydrobromic acid. It is less stable than any of the other acids described above, and it decomposes readily into iodine and hydrogen. Hydriodic acid is often used as a reducing agent.
Department of Inorganic Chemistry - HUT
HF
HCl
HX
GROUP VIIA
The Halogens
Tính chất lý học
Tính chất hóa học
Điều chế và ứng dụng
Hidro halogenua
Hợp chất chứa oxi của halogen
Department of Inorganic Chemistry - HUT
Covalent Oxides
F2O, Cl2O and Cl2O7
F2O(g) + H2O(l)  2HF(aq) + O2(g)
Cl2O(g) + H2O(l)  2HOCl(aq)
Cl2O7(l) + H2O(l)  2HClO4(aq)
Các hợp chất này đều không bền và ít có ứng dụng trong thực tế
NAMING OXOANIONS - EXAMPLES
Prefixes Root Suffixes Chlorine Bromine Iodine
per “ ” ate perchlorate perbromate periodate
[ ClO4-] [ BrO4-] [ IO4-]

“ ” ate chlorate bromate iodate
[ ClO3-] [BrO3-] [ IO3-]

“ ” ite chlorite bromite iodite
[ ClO2-] [ BrO2-] [ IO2-]

hypo “ ” ite hypochlorite hypobromite hypoiodite
[ ClO -] [ BrO -] [ IO -]
No. of O atoms
Department of Inorganic Chemistry - HUT
HOCl
Axit Hipocloro
Kém bền
Nước Javen
KClO3
Kali clorat
Thuốc nổ
CaOCl2
Department of Inorganic Chemistry - HUT
HOCl
Hipoclorit
Nước Javen
Điện phân không màng ngăn dung dịch nguội NaCl
Department of Inorganic Chemistry - HUT
CaOCl2
HOCl có tính chất oxi hóa mạnh nên nước Javen và CaOCl2 ứng dụng để tẩy trắng và tẩy uế
Department of Inorganic Chemistry - HUT
KClO3
80 0C
Axit cloric chỉ tồn tại trong dung dịch không quá 50 %, là axit mạnh, chất oxi hóa mạnh
Điện phân không màng ngăn dung dịch KCl nóng
chất oxi hóa mạnh
Ion clorat oxi hóa Cl-, Br-, I- trong môi trường axit
Không xảy ra trong môi trường trung tính, kiềm
Department of Inorganic Chemistry - HUT
Axit pecloric là axit mạnh nhất trong các axit
P, S, C
Ngòi nổ
Pháo hoa
Diêm (50 % là KClO3)
Inorganic compounds are substances not considered to be derived from hydrocarbons
The rules for naming, or nomenclature, of simple inorganic compound is covered now (organic nomenclature is covered later)
Binary compounds are compounds comprised of two different elements
The goal is to be able to convert between the chemical formula and the name
The first element in the formula is identified by its English name, the second by appending the suffix –ide to its stem (eg. compound AB)
Chemical Name as Name as
Symbol Stem First Element (A) Second Element (B)
O ox- oxygen oxide
S sulf- sulfur sulfide
N nitr- nitrogen nitride
P phosph- phosphorus phosphide
F fluor- fluorine fluoride
Cl chlor- chlorine chloride
Br brom- bromine bromide
I iod- iodine iodide
The number of each type of atom is specified with Greek prefixes
Greek Prefixes
mono- = 1 (often omitted) hexa- = 6
di- = 2 hepta- = 7
tri- = 3 octa- = 8
tetra- = 4 nona- = 9
penta- = 5 deca- = 10
Examples:
PF5 = phosphorus pentafluoride
HCl = hydrogen chloride
N2O5 = dinitrogen tetraoxide
Note: many compounds have common names, like water for H2O.