Miscibility

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Miscibility

Miscibility is a term commonly used in chemistry

Chemistry

Chemistry is the science concerned with the composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions....
that refers to the property of liquid

Liquid

Liquid is one of the principal states of matter. A liquid is a fluid that has the particles loose and can freely form a distinct surface at the boundaries of its bulk material....
s to mix in all proportions, forming a homogeneous

Homogeneity (physics)

In physics, homogeneous mixtures are mixtures that have definite, consistent composition and properties. Particles are uniformly spread. For example, any amount of a given mixture has the same composition and properties....
solution

Solution

In chemistry, a solution is a homogeneous mixture composed of two or more substances. In such a mixture, a solute is dissolved in another substance, known as a solvent....
. In principle, the term applies also to other phases

Phase (matter)

In the physical sciences, a phase is a region of space , throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, refractive index, and chemical composition....
(solids and gases), but the main focus is on the solubility

Solubility

Solubility is often seen as a property of a substance; for instance the solubility of a solid substance usually refers to the concentration of the substance in a liquid that has reached equilibrium with the substance in solid phase ....
of one liquid in another. Water

Water

Water is a common chemical substance that is essential for the survival of all known forms of life. In typical usage, water refers only to its liquid form or States of matter, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam....
and ethanol

Ethanol

Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatility , flammable, colorless liquid....
, for example, are miscible since they mix in all proportions.

By contrast, substances are said to be immiscible if in any proportion, they do not form a solution

Solution

In chemistry, a solution is a homogeneous mixture composed of two or more substances. In such a mixture, a solute is dissolved in another substance, known as a solvent....
.

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Encyclopedia

Miscibility is a term commonly used in chemistry

Chemistry

Liquid

Homogeneity (physics)

Solution

Phase (matter)

Solubility

Water

Ethanol

Solution

In chemistry, a solution is a homogeneous mixture composed of two or more substances. In such a mixture, a solute is dissolved in another substance, known as a solvent....
. For example, diethyl ether

Diethyl ether

Diethyl ether, also known as ether and ethoxyethane, is a clear, colorless, and highly flammable liquid with a low boiling point and a characteristic odor....
is fairly soluble in water, but these two solvents are not miscible since they are not soluble in all proportions.

Organic Compounds

In organic compound

Organic compound

An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered Inorganic compound....
s, the weight percent

Concentration

In chemistry, concentration is the measure of how much of a given chemical substance there is mixed with another substance. This can apply to any sort of chemical mixture, but most frequently the concept is limited to homogeneous solutions, where it refers to the amount of solute in the solvent....
of hydrocarbon

Hydrocarbon

In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. With relation to chemical terminology, aromatic hydrocarbons or arenes, alkanes, alkenes and alkyne-based compounds composed entirely of carbon or hydrogen are referred to as "pure" hydrocarbons, whereas other hydrocarbons with bonded com...
chain often determines the compound's miscibility with water. For example, among the alcohol

Alcohol

In chemistry, an alcohol is any organic compound in which a hydroxyl Functional group is bound to a carbon atom of an alkyl or substituted alkyl group....
s, ethanol has two carbon

Carbon

Carbon is a chemical element with chemical symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalence?making four electrons available to form covalent bond chemical bonds....
atom

Atom

|-! bgcolor=gray | Properties|-||}The atom is a basic unit of matter consisting of a dense, central atomic nucleus surrounded by a electron cloud of electric charge electrons....
s and is miscible with water, whereas octanol

Octanol

Octanol is a straight chain fatty alcohol with eight carbon atoms and the molecular formula CH37OH. Although the term octanol usually refers exclusively to the primary alcohol 1-octanol, there are other less common isomers of octanol such as the secondary alcohols 2-octanol, 3-octanol and 4-octanol....
with a C₈H₁₇ substituent

Substituent

In organic chemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon. The suffix -yl is used when naming organic compounds that contain a substituent....
is not. Octanol's immiscibility leads it to be used as a standard for partition equilibria

Partition equilibrium

The most common chemical equilibrium systems involve reactants and products in the same phase - either all gases or all solutions. However, it is also possible to get equilibria between substances in different phases, such as two liquids that do not mix ....
. This is also the case with lipid

Lipid

Lipids are broadly defined as any fat-soluble , naturally-occurring molecule, such as fats, oils, waxes, cholesterol, sterols, fat-soluble vitamins , monoglycerides, diglycerides, phospholipids, and others....
s; the very long carbon chains of lipids cause them to almost always be immiscible with water. Analogous situations occur for other functional group

Functional group

In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules....
s. Acetic acid

Acetic acid

Acetic acid, CH3COOH, also known as ethanoic acid, is an organic acid which gives vinegar its sour taste and pungent smell. Pure, water-free acetic acid is a colourless liquid that absorbs water from the environment , and freezes at 16.7 Celsius to a colourless crystalline solid....
(CH₃COOH) is miscible with water, whereas valeric acid

Valeric acid

Valeric acid, or pentanoic acid, is a straight-chain alkyl carboxylic acid with the chemical formula C5H10O2....
(C₄H₉COOH) is not. Simple aldehyde

Aldehyde

An aldehyde is an organic compound containing a terminal carbonyl group. This functional group, which consists of a carbon atom bonded to a hydrogen atom and double bond to an oxygen atom , is called the aldehyde group....
s and ketone

Ketone

In organic chemistry, a ketone is a type of organic compound which contains a carbonyl group bonded to two other carbon atoms in the form:Neither of the substituents R1 and R2 may be equal to hydrogen ....
s tend to be miscible with water, since a hydrogen bond

Hydrogen bond

A hydrogen bond is the attractive force between one electronegative atom and a hydrogen covalently bonded to another electronegative atom. It results from a dipole-dipole force with a hydrogen atom bonded to nitrogen, oxygen or fluorine ....
can form between the hydrogen atom of a water molecule

Water (molecule)

File:Blue-water-pool.jpgWater is the most abundant molecule on Earth's surface, constituting about 70% of the Earth's surface in liquid, solid, and gaseous states....
and the unbonded

Chemical bond

A chemical bond is the physical process responsible for the attractive interactions between atoms and molecules, and that which confers stability to diatomic and polyatomic chemical compounds....
(lone) pair of electrons on the carbonyl

Carbonyl

In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double bond to an oxygen atom : C=O.The term carbonyl can also refer to carbon monoxide as a ligand in an inorganic or organometallic complex ; in this situation, carbon is triple-bonded to oxygen : C=O....
oxygen

Oxygen

Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...
atom.

Metals

Immiscible metal

Metal

In chemistry, a metal is a chemical element whose atoms readily lose electrons to form positive ions , and form metallic bonds between other metal atoms and ionic bonds between nonmetal atoms....
s are unable to form alloy

Alloy

An alloy is a partial or complete solid solution of one or more chemical element in a metallic matrix. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may be homogeneous in distribution depending on thermal history....
s. Typically, a mixture will be possible in the molten state, but upon freezing the metals separate into layers. This property allows solid precipitates

Precipitation (chemistry)

Precipitation is the formation of a solid in a solution during a chemical reaction. When the reaction occurs, the solid formed is called the precipitate, and the liquid remaining above the solid is called the supernate....
to be formed by rapidly freezing a molten mixture of immiscible metals. One example of immiscibility in metals is copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29.It is a ductile metal with very high thermal and electrical conductivity....
and cobalt

Cobalt

Cobalt is a hard, lustrous, grey metal, a chemical element with symbol Co and atomic number 27. Although cobalt-based colors and pigments have been used since ancient times, and miners have long used the name kobold ore for some minerals, cobalt was only discovered in 1735 by Georg Brandt....
, where rapid freezing to form solid precipitates has been used to create granular GMR materials.

There are examples of immiscible metals in the liquid state. One with industrial importance is that liquid zinc

Zinc

Zinc is a metallic chemical element with the symbol Zn and atomic number 30. It is a first-row transition metal of the group 12 element of the periodic table....
and liquid silver

Silver

Silver is a chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal....
are immiscible in liquid lead

Lead

Lead is a main-group Chemical element with symbol Pb and atomic number 82. Lead is a soft, malleable poor metal, also considered to be one of the heavy metal ....
, while silver

Silver

Parkes process

The Parkes process is a pyrometallurgical industrial process for removing silver from lead, during the production of bullion. It is an example of liquid-liquid extraction....
, whereby lead containing any amount of silver is melted with zinc. The silver migrates to the zinc, which is skimmed off the top of the two phase liquid, and the zinc is boiled away leaving nearly pure silver.

Effect of Entropy

Miscibility is partly a function of entropy

Entropy

In many branches of science, entropy is a measure of the disorder of a system. The concept of entropy is particularly notable as it is applied across physics, information theory and mathematics....
, and so is seen more commonly in states of matter that are more entropic. Gases mix quite readily, but solids only rarely display miscibility. Two useful exceptions to this rule are solid solutions of copper with nickel

Nickel

Nickel is a chemical element, with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge....
(the cupronickel

Cupronickel

Cupronickel or Coppernickel is an alloy of copper, nickel and strengthening impurities, such as iron and manganese. Cupronickel does not corrosion in seawater, because its electrode potential is adjusted to be neutral with regard to seawater....
used in coins and specialty plumbing), and of silicon

Silicon

Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. The atomic mass is 28.0855....
with germanium

Germanium

Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard, greyish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon....
(used in electronics). Substances with extremely low configurational entropy

Configuration entropy

Configuration entropy is the entropy associated with the geometric configuration of individual components comprising a distributed physical system....
, especially polymer

Polymer

A polymer is a large molecule composed of repeating structural units typically connected by covalent chemical bonds. While polymer in popular usage suggests plastic, the term actually refers to a large class of natural and synthetic materials with a variety of properties....
s, are unlikely to be miscible in one another even in the liquid state.

Determination

Miscibility of two materials is often determined optically. When the two miscible liquids are combined, the resulting liquid is clear. If the mixture is cloudy the two materials are immiscible. Care must be taken with this determination. If the index of refraction

Refractive index

The refractive index of a medium is a measure for how much the speed of light is reduced inside the medium. For example, typical soda-lime glass has a refractive index of 1.5, which means that in glass, light travels at times the speed of light in a vacuum....
of the two materials are similar, an immiscible mixture may be clear and give an incorrect determination that the two liquids are miscible.

Miscibility

Organic Compounds

Metals

Effect of Entropy

Determination

See also