Lithium sulfate is a white inorganic salt with the
formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...
Li2 S O4. It is the lithium
salt
Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...
of
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...
.
Properties
Physical properties
Lithium sulfate is
soluble
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution.
The extent of the solubil ...
in water, though it does not follow the usual trend of increasing solubility of most salts with temperature. To the contrary, its solubility in water decreases with increasing temperature, as its dissolution is an
exothermic
In thermodynamics, an exothermic process () is a thermodynamic process or reaction that releases energy from the system to its surroundings, usually in the form of heat, but also in a form of light (e.g. a spark, flame, or flash), electricity (e ...
process. This relatively unusual property, also called retrograde
solubility
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution.
The extent of the solubil ...
, is shared with few
inorganic compounds
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistr ...
, such as
calcium hydroxide
Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca( OH)2. It is a colorless crystal or white powder and is produced when quicklime (calcium oxide) is mixed or slaked with water. It has m ...
(
portlandite
Portlandite is a hydroxide-bearing mineral typically included in the oxide mineral class. It is the naturally occurring form of calcium hydroxide (Ca(OH)2) and the calcium analogue of brucite (Mg(OH)2).
Occurrence
Portlandite occurs in a variety ...
, an important mineral phase of hydrated cement paste), the
calcium sulfate
Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO4 and related hydrates. In the form of γ-anhydrite (the anhydrous form), it is used as a desiccant. One particular hydrate is better known as plaster of Pari ...
s (
gypsum
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. ...
,
bassanite
Bassanite is a calcium sulfate mineral with formula CaSO4· H2O or 2CaSO4·H2O. In other words it has half a water molecule per CaSO4 unit, hence its synonym ''calcium sulfate hemihydrate''.
Bassanite was first described in 1910 for an occurrenc ...
, and
anhydrite
Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the ...
) and
lanthanoid
The lanthanide () or lanthanoid () series of chemical elements comprises the 15 metallic chemical elements with atomic numbers 57–71, from lanthanum through lutetium. These elements, along with the chemically similar elements scandium and yttr ...
sulfates
The sulfate or sulphate ion is a polyatomic
A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge t ...
whose dissolution reactions are also exothermic. The retrograde solubility is common for gases dissolution in water, but less frequently encountered for the dissolution of solids.
Calcium carbonate also exhibits a retrograde solubility, but it also depends on the behavior of dissolution in the calco-carbonate equilibria.
Lithium sulfate crystals, being
piezoelectric
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied Stress (mechanics), mechanical s ...
, are also used in ultrasound-type non-destructive testing because they are very efficient sound receivers. However, they do suffer in this application because of their water solubility.
Since it has
hygroscopic properties, the most common form of lithium sulfate is lithium sulfate monohydrate. Anhydrous lithium sulfate has a density of 2.22 g/cm
3 but, weighing lithium sulfate anhydrous can become cumbersome as it must be done in a water lacking atmosphere.
Lithium sulfate has
pyroelectric properties. When aqueous lithium sulfate is heated, the electrical conductivity also increases. The molarity of lithium sulfate also plays a role in the electrical conductivity; optimal conductivity is achieved at 2 M and then decreases.
When solid lithium sulfate is dissolved in water it has an
endothermic
In thermochemistry, an endothermic process () is any thermodynamic process with an increase in the enthalpy (or internal energy ) of the system.Oxtoby, D. W; Gillis, H.P., Butler, L. J. (2015).''Principle of Modern Chemistry'', Brooks Cole. p. ...
disassociation
Dissociation, as a concept that has been developed over time, is a wide array of experiences, ranging from a mild emotional detachment from the immediate surroundings, to a more severe disconnection from physical and emotional experiences. The m ...
. This is different from
sodium sulfate
Sodium sulfate (also known as sodium sulphate or sulfate of soda) is the inorganic compound with formula Na2SO4 as well as several related hydrates. All forms are white solids that are highly soluble in water. With an annual production of 6 milli ...
which has an exothermic disassociation. However, the exact energy of disassociation is difficult to quantify as it seems also to depend on the quantity (number of mols) of the salt added to water. Small amounts of dissolved lithium sulfate induce a much greater temperature change per mol than large amounts.
Crystal properties
Lithium sulfate has two different
crystal phases. In common phase II form, Lithium sulfate has a sphenoidal
monoclinic crystal system that has edge lengths of a = 8.23Å b = 4.95Å c = 8.47Å β = 107.98°. When lithium sulfate is heated passed 130 °C it changes to a water free state but retains its crystal structure. It is not until 575 °C when there is a transformation from phase II to phase I. The crystal structure changes to a face centered
cubic crystal system
In crystallography, the cubic (or isometric) crystal system is a crystal system where the Crystal_structure#Unit_cell, unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals.
There ...
, with an edge length of 7.07Å. During this phase change, the density of lithium sulfate changes from 2.22 to 2.07 g/cm
3.
Uses
Lithium sulfate is used to treat
bipolar disorder
Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that last from days to weeks each. If the elevated mood is severe or associated with ...
(see
lithium pharmacology
Certain lithium compounds, also known as lithium salts, are used as psychiatric medication, primarily for bipolar disorder and for major depressive disorder. In these disorders, it sometimes reduces the risk of suicide. Lithium is taken orally. ...
).
Lithium sulfate is researched as a potential component of ion conducting glasses.
Transparent conducting film
Transparent conducting films (TCFs) are thin films of optically transparent and electrically conductive material. They are an important component in a number of electronic devices including liquid-crystal displays, OLEDs, touchscreens and photov ...
is a highly investigated topic as they are used in applications such as solar panels and the potential for a new class of battery. In these applications, it is important to have a high lithium content; the more commonly known binary lithium borate (Li₂O · B₂O₃) is difficult to obtain with high lithium concentrations and difficult to keep as it is hygroscopic. With the addition of lithium sulfate into the system, an easily produced, stable, high lithium concentration glass is able to be formed. Most of the current transparent ionic conducting films are made of organic plastics, and it would be ideal if an inexpensive stable inorganic glass could be developed.
Lithium sulfate has been tested as an additive for
Portland cement
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th c ...
to accelerate curing with positive results. Lithium sulfate serves to speed up the hydration reaction (see
Cement
A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate) together. Cement mix ...
) which decreases the curing time. A concern with decreased curing time is the strength of the final product, but when tested, lithium sulfate doped Portland cement had no observable decrease in strength.
Lithium-ion batteries
( · ) containing around 10% lithium is a useful chemical for the production of
lithium hydroxide
Lithium hydroxide is an inorganic compound with the formula LiOH. It can exist as anhydrous or hydrated, and both forms are white hygroscopic solids. They are soluble in water and slightly soluble in ethanol. Both are available commercially. While ...
for the lithium-ion battery materials supply chain. It is a less reactive material than LiOH, and hence can be more easily stored and transported.
Feedstock of hard-rock
spodumene
Spodumene is a pyroxene mineral consisting of lithium aluminium inosilicate, Li Al( Si O3)2, and is a source of lithium. It occurs as colorless to yellowish, purplish, or lilac kunzite (see below), yellowish-green or emerald-green hiddenite, pri ...
concentrate is processed by acid roasting, followed by water leaching, achieving a lithium recovery of 84-88%. Evaporation is then applied to the purified leach solution resulting in a primary lithium sulphate solid product made up mostly of lithium sulphate monohydrate ( · ).
Medication
Lithium ion (Li
+) is used in psychiatry for the treatment of
mania
Mania, also known as manic syndrome, is a mental and behavioral disorder defined as a state of abnormally elevated arousal, affect, and energy level, or "a state of heightened overall activation with enhanced affective expression together wit ...
, endogenous depression, and psychosis, and also for treatment of
schizophrenia
Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...
. Usually
lithium carbonate
Lithium carbonate is an inorganic compound, the lithium salt (chemistry), salt of carbonate with the chemical formula, formula . This white Salt (chemistry), salt is widely used in the processing of metal oxides. It is listed on the World Health O ...
() is applied, but sometimes
lithium citrate
Lithium citrate (Li3C6H5O7) is a chemical compound of lithium and citrate that is used as a mood stabilizer in psychiatric treatment of manic states and bipolar disorder. There is extensive pharmacology of lithium, the active component of this s ...
(), lithium sulfate or lithium oxy-
butyrate
The conjugate acids are in :Carboxylic acids.
{{Commons category, Carboxylate ions, Carboxylate anions
Carbon compounds
Oxyanions ...
are used as alternatives.
[Haddad, L.M., Winchester, J.F. Clinical Management of Poisoning and Drug Overdose. 1990 2nd ed, 656-665] Li
+ is not metabolized. Because of Li
+ chemical similarity to
sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable iso ...
(Na
+) and
potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosphe ...
(K
+) cations, it may interact or interfere with the biochemical pathways of these substances and displace these cations from intra- or extracellular compartments of the body. Li
+ seems to be transported out of nerve and muscle cells by the active
sodium pump
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable isot ...
, although less efficiently.
Lithium sulfate has a rapid
gastrointestinal
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...
absorption rate (within a few minutes), and complete following oral administration of tablets or the liquid form.
It quickly diffuses into the
liver
The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...
and
kidney
The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...
s but requires 8–10 days to reach a body equilibrium. Li
+ produces many
metabolic
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
and
neuroendocrine
Neuroendocrine cells are cells that receive neuronal input (through neurotransmitters released by nerve cells or neurosecretory cells) and, as a consequence of this input, release messenger molecules ( hormones) into the blood. In this way they b ...
changes, but no conclusive evidence favors one particular mode of action.
For example, Li
+ interacts with
neurohormone A neurohormone is any hormone produced and released by neuroendocrine cells (also called neurosecretory cells) into the blood. By definition of being hormones, they are secreted into the circulation for systemic effect, but they can also have a role ...
s, particularly the
biogenic amines
A biogenic amine is a biogenic substance with one or more amine groups. They are basic nitrogenous compounds formed mainly by decarboxylation of amino acids or by amination and transamination of aldehydes and ketones. Biogenic amines are organic b ...
,
serotonin
Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and vas ...
(5-hydroxy
tryptamine
Tryptamine is an indolamine metabolite of the essential amino acid, tryptophan. The chemical structure is defined by an indole ─ a fused benzene and pyrrole ring, and a 2-aminoethyl group at the second carbon (third aromatic atom, with the f ...
) and
norepinephrine
Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad'', ...
, which provides a probable mechanism for the beneficial effects in
psychiatric disorder
A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitt ...
s, e.g.
mania
Mania, also known as manic syndrome, is a mental and behavioral disorder defined as a state of abnormally elevated arousal, affect, and energy level, or "a state of heightened overall activation with enhanced affective expression together wit ...
s. In the
central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...
(CNS), Li
+ affects
nerve
A nerve is an enclosed, cable-like bundle of nerve fibers (called axons) in the peripheral nervous system.
A nerve transmits electrical impulses. It is the basic unit of the peripheral nervous system. A nerve provides a common pathway for the e ...
excitation,
synaptic transmission
Neurotransmission (Latin: ''transmissio'' "passage, crossing" from ''transmittere'' "send, let through") is the process by which signaling molecules called neurotransmitters are released by the axon terminal of a neuron (the presynaptic neuron), ...
, and
neuronal
A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. No ...
metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
. Li
+ stabilizes serotoninergic
neurotransmission
Neurotransmission (Latin: ''transmissio'' "passage, crossing" from ''transmittere'' "send, let through") is the process by which signaling molecules called neurotransmitters are released by the axon terminal of a neuron (the presynaptic neuron), ...
.
Organic chemistry synthesis
Lithium sulfate is being used as a
catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
for the
elimination reaction
An elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one- or two-step mechanism. The one-step mechanism is known as the E2 reaction, and the two-step mechanism is known as the E1 ...
for transforming n-butyl bromide to 1-butene at close to 100% yields at a range of 320 °C to 370 °C. The yields of this reaction change dramatically if heated beyond this range as higher yields of 2-butene is formed.
[Noller, H., Rosa-Brusin, M. and Andréu, P. (1967), Stereoselective Synthesis of 1-Butene with Lithium Sulfate as Elimination Catalyst. Angew. Chem. Int. Ed. Engl., 6: 170–171. doi:10.1002/anie.196701702]
References
{{Authority control
Sulfates
Lithium salts
Mood stabilizers