Lithium nitrite

Last updated
Lithium nitrite
Names
Preferred IUPAC name
Lithium nitrite
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.033.600 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 23-976-1
PubChem CID
  • InChI=1S/Li.HNO2/c;2-1-3/h;(H,2,3)/q+1;/p-1
    Key: IDNHOWMYUQKKTI-UHFFFAOYSA-M
  • InChI=1/Li.HNO2/c;2-1-3/h;(H,2,3)/q+1;/p-1
    Key: IDNHOWMYUQKKTI-REWHXWOFAV
  • [Li+].N(=O)[O-]
Properties
LiNO2
Molar mass 52.9465 g/mol
Appearancewhite, hygroscopic crystals [1]
Melting point 222 °C (432 °F; 495 K) [1]
49 wt.% (20 °C) [2]
Thermochemistry [3]
Std molar
entropy
(S298)
96.0 J/mol K
−372.4 kJ/mol
-302.0 kJ/mol
Enthalpy of fusion fHfus)
9.2 kJ/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Lithium nitrite is the lithium salt of nitrous acid, with formula LiNO2. This compound is hygroscopic and very soluble in water. It is used as a corrosion inhibitor in mortar. [4] It is also used in the production of explosives, due to its ability to nitrosate ketones under certain conditions. [5]

Contents

Preparation

Lithium nitrate (LiNO3) will undergo thermal decomposition above 500 °C to yield the evolution of lithium nitrite and oxygen as in the following reaction: [6]

2LiNO3 → 2LiNO2 + O2 (at ~500 °C)

Lithium nitrite can also be prepared by the reaction of nitric oxide (NO) with lithium hydroxide (LiOH) as shown below: [6]

4NO + 2LiOH → 2LiNO2 + N2O + H2O
6NO + 4LiOH → 4LiNO2 + N2 + 2H2O

Crystallization and crystal structure

Lithium nitrite crystals can be obtained most efficiently by reacting lithium sulfate and barium nitrite in an aqueous solution. However, these crystals can also be prepared by mixing equal amounts of lithium sulfate and potassium nitrite in highly concentrated aqueous solution. This is followed by considerable evaporation and filtration, which removes the resulting precipitate of potassium sulfate and lithium potassium sulfate after further evaporation and extraction with absolute alcohol. [7]

Lithium nitrite is exceptionally soluble in absolute alcohol. However, potassium nitrite is not very soluble. This makes absolute alcohol a choice solvent for the crystallization of lithium nitrite because the crystals can be extracted in a substantially pure state. The alcoholic solution will leave a white residue of small crystals upon evaporation. The addition of a small amount of water to this residue will yield the larger needle-shaped crystals of lithium nitrite monohydrate (LiNO2·H2O). [7]

The above methods will result in flat, needle-shaped crystals. These crystals are white and typically 1–2 cm. in length. Below 100 °C, these crystals will melt in their own water of crystallization and will tend to lose water slowly. Rapid dehydration will occur at temperatures above 160 °C as well as a minuscule loss of nitrogen oxide. This rapid dehydration leaves behind a residue which consists almost entirely of the anhydrous salt. [7] This anhydrous salt is extraordinarily soluble in water and will readily form a supersaturated solution. Monohydrate crystals will deposit from this supersaturated solution upon cooling or with the addition of ready formed salt crystals. [7]

Industrial uses

Reinforcement bars, ready mixed concrete materials, and repair materials are often subject to corrosion. These resources will rapidly degrade due to chloride attack and carbonatation. This not only affects the service lives of such materials, but it also requires a considerable cost for the repair of such defects. Lithium nitrite and calcium nitrite are generally used in the construction industry as a means to protect reinforced concrete structures from corrosion. Unlike calcium nitrite inhibitors, lithium nitrite is particularly valued for corrosion inhibition and resistance of carbonation when an accelerated hardening process is not used and when a high concentration of 10% or more cement is added by weight. [4]

Generally speaking, studying the effectiveness of such inhibitors has been done using destructive methods. These studies require placing specimens to accelerated corrosion and measuring the degree of corrosion. "However, it is extremely difficult to measure the effect of corrosion inhibitors in actual structures using a destructive method."

Recently, sensors that can measure changes in electrical resistance due to the corrosion in iron and thus indicate the degree of corrosion of a material have been developed. These sensors provide a non-destructive way to evaluate the degree of corrosion in concrete materials. Therefore, the effect of lithium nitrite as a corrosion inhibitor has also been studied by non-destructive means. [4]

A study was conducted in Korea to experimentally determine the most effective dose and performance of lithium nitrite corrosion inhibitors. This experiment employed the molar ratio of nitrite ions to chloride ions (NO2/Cl) as a test parameter. This study concluded that a lithium nitrite dosage of 0.6 in the nitrite-chloride ion molar ratio is a successful dosage for mortar containing chlorides. [4]

Related Research Articles

In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively charged sodium ions and negatively charged chloride ions.

<span class="mw-page-title-main">Sodium chloride</span> Chemical compound with formula NaCl

Sodium chloride, commonly known as table salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. Sodium chloride is the salt most responsible for the salinity of seawater and of the extracellular fluid of many multicellular organisms. In its edible form, salt is commonly used as a condiment and food preservative. Large quantities of sodium chloride are used in many industrial processes, and it is a major source of sodium and chlorine compounds used as feedstocks for further chemical syntheses. Another major application of sodium chloride is deicing of roadways in sub-freezing weather.

<span class="mw-page-title-main">Sodium carbonate</span> Chemical compound

Sodium carbonate is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield alkaline solutions in water. Historically, it was extracted from the ashes of plants grown in sodium-rich soils, and because the ashes of these sodium-rich plants were noticeably different from ashes of wood, sodium carbonate became known as "soda ash". It is produced in large quantities from sodium chloride and limestone by the Solvay process, as well as by carbonating sodium hydroxide which is made using the Chlor-alkali process.

<span class="mw-page-title-main">Precipitation (chemistry)</span> Chemical process leading to the settling of an insoluble solid from a solution

In an aqueous solution, precipitation is the process of transforming a dissolved substance into an insoluble solid from a supersaturated solution. The solid formed is called the precipitate. In case of an inorganic chemical reaction leading to precipitation, the chemical reagent causing the solid to form is called the precipitant.

<span class="mw-page-title-main">Dinitrogen pentoxide</span> Chemical compound

Dinitrogen pentoxide is the chemical compound with the formula N2O5. It is one of the binary nitrogen oxides, a family of compounds that only contain nitrogen and oxygen. It exists as colourless crystals that sublime slightly above room temperature, yielding a colorless gas.

<span class="mw-page-title-main">Potassium sulfate</span> Chemical compound

Potassium sulfate (US) or potassium sulphate (UK), also called sulphate of potash (SOP), arcanite, or archaically potash of sulfur, is the inorganic compound with formula K2SO4, a white water-soluble solid. It is commonly used in fertilizers, providing both potassium and sulfur.

<span class="mw-page-title-main">Lead(II) chloride</span> Chemical compound

Lead(II) chloride (PbCl2) is an inorganic compound which is a white solid under ambient conditions. It is poorly soluble in water. Lead(II) chloride is one of the most important lead-based reagents. It also occurs naturally in the form of the mineral cotunnite.

<span class="mw-page-title-main">Lithium chloride</span> Chemical compound

Lithium chloride is a chemical compound with the formula LiCl. The salt is a typical ionic compound (with certain covalent characteristics), although the small size of the Li+ ion gives rise to properties not seen for other alkali metal chlorides, such as extraordinary solubility in polar solvents (83.05 g/100 mL of water at 20 °C) and its hygroscopic properties.

<span class="mw-page-title-main">Calcium nitrate</span> Chemical compound

Calcium nitrate, also called Norgessalpeter or Norwegian salpeter, is an inorganic compound with the formula Ca(NO3)2(H2O)x. The anhydrous compound, which is rarely encountered, absorbs moisture from the air to give the tetrahydrate. Both anhydrous and hydrated forms are colourless salts. Calcium nitrate is mainly used as a component in fertilizers, but it has other applications. Nitrocalcite is the name for a mineral which is a hydrated calcium nitrate that forms as an efflorescence where manure contacts concrete or limestone in a dry environment as in stables or caverns. A variety of double salts are known including calcium ammonium nitrate decahydrate (NH4NO3·5Ca(NO3)2·10H2O) and calcium potassium nitrate (Ca(NO3)2·4KNO3).

<span class="mw-page-title-main">Pitting corrosion</span> Form of insidious localized corrosion in which a pit develops at the anode site

Pitting corrosion, or pitting, is a form of extremely localized corrosion that leads to the random creation of small holes in metal. The driving power for pitting corrosion is the depassivation of a small area, which becomes anodic while an unknown but potentially vast area becomes cathodic, leading to very localized galvanic corrosion. The corrosion penetrates the mass of the metal, with a limited diffusion of ions.

<span class="mw-page-title-main">Ammonium nitrite</span> Chemical compound

Ammonium nitrite, [NH4]NO2, is the ammonium salt of nitrous acid. It is not used in pure isolated form since it is highly unstable and decomposes into water and nitrogen, even at room temperature.

<span class="mw-page-title-main">Lithium fluoride</span> Chemical compound

Lithium fluoride is an inorganic compound with the chemical formula LiF. It is a colorless solid that transitions to white with decreasing crystal size. Although odorless, lithium fluoride has a bitter-saline taste. Its structure is analogous to that of sodium chloride, but it is much less soluble in water. It is mainly used as a component of molten salts. Partly because Li and F are both light elements, and partly because F2 is highly reactive, formation of LiF from the elements releases one of the highest energies per mass of reactants, second only to that of BeO.

<span class="mw-page-title-main">Aluminium nitrate</span> Chemical compound

Aluminium nitrate is a white, water-soluble salt of aluminium and nitric acid, most commonly existing as the crystalline hydrate, aluminium nitrate nonahydrate, Al(NO3)3·9H2O.

<span class="mw-page-title-main">Silver chromate</span> Chemical compound

Silver chromate is an inorganic compound with formula Ag2CrO4 which appears as distinctively coloured brown-red crystals. The compound is insoluble and its precipitation is indicative of the reaction between soluble chromate and silver precursor salts (commonly potassium/sodium chromate with silver nitrate). This reaction is important for two uses in the laboratory: in analytical chemistry it constitutes the basis for the Mohr method of argentometry, whereas in neuroscience it is used in the Golgi method of staining neurons for microscopy.

<span class="mw-page-title-main">Lithium sulfate</span> Chemical compound

Lithium sulfate is a white inorganic salt with the formula Li2SO4. It is the lithium salt of sulfuric acid.

<span class="mw-page-title-main">Lithium aluminate</span> Chemical compound

Lithium aluminate, also called lithium aluminium oxide, is an inorganic chemical compound, an aluminate of lithium. In microelectronics, lithium aluminate is considered as a lattice matching substrate for gallium nitride. In nuclear technology, lithium aluminate is of interest as a solid tritium breeder material, for preparing tritium fuel for nuclear fusion. Lithium aluminate is a layered double hydroxide (LDH) with a crystal structure resembling that of hydrotalcite. Lithium aluminate solubility at high pH is much lower than that of aluminium oxides. In the conditioning of low- and intermediate level radioactive waste (LILW), lithium nitrate is sometimes used as additive to cement to minimise aluminium corrosion at high pH and subsequent hydrogen production. Indeed, upon addition of lithium nitrate to cement, a passive layer of LiH(AlO
2
)
2
· 5 H
2
O
is formed onto the surface of metallic aluminium waste immobilised in mortar. The lithium aluminate layer is insoluble in cement pore water and protects the underlying aluminium oxide covering the metallic aluminium from dissolution at high pH. It is also a pore filler. This hinders the aluminium oxidation by the protons of water and reduces the hydrogen evolution rate by a factor of 10.

Barium perchlorate is a powerful oxidizing agent, with the formula Ba(ClO4)2. It is used in the pyrotechnic industry.

Calcium nitrite is an inorganic compound with the chemical formula Ca(NO
2
)
2
. In this compound, as in all nitrites, nitrogen is in a +3 oxidation state. It has many applications such as antifreeze, rust inhibitor of steel and wash heavy oil.

<span class="mw-page-title-main">Cerium nitrates</span> Chemical compound

Cerium nitrate refers to a family of nitrates of cerium in the +3 or +4 oxidation state. Often these compounds contain water, hydroxide, or hydronium ions in addition to cerium and nitrate. Double nitrates of cerium also exist.

A nitrate nitrite, or nitrite nitrate, is a coordination complex or other chemical compound that contains both nitrite and nitrate anions (NO3 and NO2). They are mixed-anion compounds, and they are mixed-valence compounds. Some have third anions. Many nitrite nitrate compounds are coordination complexes of cobalt. Such a substance was discovered by Wolcott Gibbs and Frederick Genth in 1857.

References

  1. 1 2 Haynes, p. 4.70
  2. Haynes, p. 5.170
  3. Haynes, pp. 5.25, 6.159
  4. 1 2 3 4 Lee, Han-Seung; Shin, Sung-Woo (2007). "Evaluation on the effect of lithium nitrite corrosion inhibitor by the corrosion sensors embedded in mortar". Construction and Building Materials. 21: 1–6. doi:10.1016/j.conbuildmat.2006.01.004.
  5. Chen, M. F.; MacDonald, S. F. (1974). "Nitrosation with Lithium Nitrite". Canadian Journal of Chemistry. 52 (9): 1760–1761. doi: 10.1139/v74-253 .
  6. 1 2 Greenwood, N. N. and Earnshaw, A. (1997) Chemistry of the Elements, 2nd ed.; Reed Educational and Professional Publishing Ltd: Oxford. Ch. 4.3.5, p. 90. ISBN   0750633654
  7. 1 2 3 4 Ball, Walter Craven; Abram, Harold Helling (1913). "CCXXV.—The nitrites of thallium, lithium, caesium, and rubidium". J. Chem. Soc., Trans. 103: 2130–2134. doi:10.1039/CT9130302130.

Cited sources