Rubidium azide

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Rubidium azide
Rubidium azide structure.png
RbN3.png
Names
IUPAC name
Rubidium(1+);azide
Other names
Rubidium azide
Identifiers
3D model (JSmol)
ChemSpider
PubChem CID
  • InChI=1S/N3.Rb/c1-3-2;/q-1;+1 Yes check.svgY
    Key: GEWQYWRSUXOTOL-UHFFFAOYSA-N Yes check.svgY
  • [N-]=[N+]=[N-].[Rb+]
Properties
RbN3
Molar mass 127.49 g⋅mol−1
AppearanceColorless needles [1]
Density 2.79 g⋅cm−3 [1] [2]
Melting point 317–321 °C (603–610 °F; 590–594 K) [2] [3]
Boiling point Decomposes
  • 107.1 g/100 g (16 °C)
  • 114.1 g/100 g (17 °C) [4]
Solubility 0.182 g/100 g (16 °C, ethanol) [4]
Thermochemistry
−0.1 kcal⋅mol−1 [2]
Hazards
NFPA 704 (fire diamond)
NFPA 704.svgHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 0: Will not burn. E.g. waterInstability 3: Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water, or will detonate if severely shocked. E.g. hydrogen peroxideSpecial hazards (white): no code
4
0
3
Related compounds
Other anions
Rubidium nitrate
Other cations
Lithium azide
Sodium azide
Potassium azide
Silver azide
Ammonium azide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Rubidium azide is an inorganic compound with the formula Rb N 3. It is the rubidium salt of the hydrazoic acid HN3. Like most azides, it is explosive. [3]

Contents

Preparation

Rubidium azide can be created by the reaction between rubidium sulfate and barium azide which results in formation of easily separated insoluble barium sulfate: [4]

Rb2SO4 + Ba(N3)2 → 2 RbN3 + BaSO4

In at least one study, rubidium azide was produced by the reaction between butyl nitrite, hydrazine monohydrate, and rubidium hydroxide in the presence of ethanol:

C4H9ONO + N2H4·H2O + RbOH → RbN3 + C4H9OH + 3 H2O

This formula is typically used to synthesize potassium azide from caustic potash. [5]

Uses

Rubidium azide has been investigated for possible use in alkali vapor cells, which are components of atomic clocks, atomic magnetometers and atomic gyroscopes. Azides are desirable starting materials because they decompose into rubidium metal and nitrogen gas when exposed to UV light. According to one publication:

Among the different techniques used to fill microfabricated alkali vapor cell [sic], UV decomposition of rubidium azide (RbN3) into metallic Rb and nitrogen in Al2O3 coated cells is a very promising approach for low-cost wafer-level fabrication. [6]

Structure

At room temperature, rubidium azide has the same structure as potassium hydrogen fluoride; a distorted caesium chloride structure. At 315 °C and 1 atm, rubidium azide will transition to the normal caesium chloride structure. The II/I transition temperature of rubidium azide is within 2 °C of its melting point. [3]

Rubidium azide has a high pressure structure transition, which occurs at about 4.8 kilobars of pressure at 0 °C. The transition boundary of the II/III transition can be defined by the relationship , where is the pressure in kilobars and is the temperature in degrees Celsius. [3]

Reactions

As with all azides, it will decompose and release nitrogen gas when heated or severely shocked:

2 RbN3 → 2 Rb + 3 N2

Discharge rubidium azide in nitrogen gas will produce rubidium nitride. [7]

Hazards

At 4.1 kilobars of pressure and about 460 °C, rubidium azide will explosively decompose. [3] Under normal circumstances, it explodes at 395 °C. [2] It also decomposes upon exposure to ultraviolet light. [6]

Rubidium azide is very sensitive to mechanical shock, with an impact sensitivity comparable to that of TNT. [8]

Like all azides, rubidium azide is toxic.

Related Research Articles

<span class="mw-page-title-main">Alkali metal</span> Group of highly reactive chemical elements

The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). Together with hydrogen they constitute group 1, which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in their having very similar characteristic properties. Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. This family of elements is also known as the lithium family after its leading element.

<span class="mw-page-title-main">Caesium</span> Chemical element, symbol Cs and atomic number 55

Caesium is a chemical element; it has symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of 28.5 °C, which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium has physical and chemical properties similar to those of rubidium and potassium. It is pyrophoric and reacts with water even at −116 °C (−177 °F). It is the least electronegative element, with a value of 0.79 on the Pauling scale. It has only one stable isotope, caesium-133. Caesium is mined mostly from pollucite. Caesium-137, a fission product, is extracted from waste produced by nuclear reactors. It has the largest atomic radius of all elements whose radii have been measured or calculated, at about 260 picometers.

<span class="mw-page-title-main">Nitrogen</span> Chemical element, symbol N and atomic number 7

Nitrogen is a chemical element; it has symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N2, a colorless and odorless diatomic gas. N2 forms about 78% of Earth's atmosphere, making it the most abundant uncombined element in air. Because of the volatility of nitrogen compounds, nitrogen is relatively rare in the solid parts of the Earth.

<span class="mw-page-title-main">Rubidium</span> Chemical element, symbol Rb and atomic number 37

Rubidium is a chemical element; it has symbol Rb and atomic number 37. It is a very soft, whitish-grey solid in the alkali metal group, similar to potassium and caesium. Rubidium is the first alkali metal in the group to have a density higher than water. On Earth, natural rubidium comprises two isotopes: 72% is a stable isotope 85Rb, and 28% is slightly radioactive 87Rb, with a half-life of 48.8 billion years—more than three times as long as the estimated age of the universe.

In chemistry, azide is a linear, polyatomic anion with the formula N−3 and structure −N=N+=N−. It is the conjugate base of hydrazoic acid HN3. Organic azides are organic compounds with the formula RN3, containing the azide functional group. The dominant application of azides is as a propellant in air bags.

<span class="mw-page-title-main">Hydrazoic acid</span> Unstable and toxic chemical compound

Hydrazoic acid, also known as hydrogen azide, azic acid or azoimide, is a compound with the chemical formula HN3. It is a colorless, volatile, and explosive liquid at room temperature and pressure. It is a compound of nitrogen and hydrogen, and is therefore a pnictogen hydride. The oxidation state of the nitrogen atoms in hydrazoic acid is fractional and is -1/3. It was first isolated in 1890 by Theodor Curtius. The acid has few applications, but its conjugate base, the azide ion, is useful in specialized processes.

<span class="mw-page-title-main">Ozonide</span> Polyatomic ion (O3, charge –1), or cyclic compounds made from ozone and alkenes

Ozonide is the polyatomic anion O−3. Cyclic organic compounds formed by the addition of ozone to an alkene are also called ozonides.

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

Caesium chromate or cesium chromate is an inorganic compound with the formula Cs2CrO4. It is a yellow crystalline solid that is the caesium salt of chromic acid, and it crystallises in the orthorhombic system.

The chemical element nitrogen is one of the most abundant elements in the universe and can form many compounds. It can take several oxidation states; but the most common oxidation states are -3 and +3. Nitrogen can form nitride and nitrate ions. It also forms a part of nitric acid and nitrate salts. Nitrogen compounds also have an important role in organic chemistry, as nitrogen is part of proteins, amino acids and adenosine triphosphate.

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

Potassium azide is the inorganic compound having the formula KN3. It is a white, water-soluble salt. It is used as a reagent in the laboratory.

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

Lithium azide is the lithium salt of hydrazoic acid. It is an unstable and toxic compound that decomposes into lithium and nitrogen when heated.

<span class="mw-page-title-main">Barium azide</span> Chemical compound

Barium azide is an inorganic azide with the formula Ba(N3)2. It is a barium salt of hydrazoic acid. Like most azides, it is explosive. It is less sensitive to mechanical shock than lead azide.

Rubidium hydrogen sulfate, sometimes referred to as rubidium bisulfate, is the half neutralized rubidium salt of sulfuric acid. It has the formula RbHSO4.

<span class="mw-page-title-main">Fluorine azide</span> Chemical compound

Fluorine azide or triazadienyl fluoride is a yellow green gas composed of nitrogen and fluorine with formula FN3. Its properties resemble those of ClN3, BrN3, and IN3. The bond between the fluorine atom and the nitrogen is very weak, leading to this substance being very unstable and prone to explosion. Calculations show the F–N–N angle to be around 102° with a straight line of 3 nitrogen atoms.

<span class="mw-page-title-main">Caesium azide</span> Chemical compound

Caesium azide or cesium azide is an inorganic compound of caesium and nitrogen. It is a salt of azide with the formula CsN3.

<span class="mw-page-title-main">Boron triazide</span> Chemical compound

Boron triazide, also known as triazidoborane, is a thermally unstable compound of boron and nitrogen with a nitrogen content of 92.1 %. Formally, it is the triazido derivative of borane and is a covalent inorganic azide. The high-energy compound, which has the propensity to undergo spontaneous explosive decomposition, was first described in 1954 by Egon Wiberg and Horst Michaud of the University of Munich.

<span class="mw-page-title-main">Rubidium oxalate</span> Chemical compound

Rubidium oxalate is a chemical compound with the chemical formula Rb2C2O4. It is a rubidium salt of oxalic acid. It consists of rubidium cations Rb+ and oxalate anions C2O2−4. Rubidium oxalate forms a monohydrate Rb2C2O4·H2O.

<span class="mw-page-title-main">Rubidium permanganate</span> Chemical compound

Rubidium permanganate is the permanganate salt of rubidium, with the chemical formula RbMnO
4.

References

  1. 1 2 Perry, Dale (1995-05-17). Handbook of Inorganic Compounds. Online. p. 333. ISBN   9780849386718 . Retrieved 31 January 2018.{{cite book}}: CS1 maint: location missing publisher (link)
  2. 1 2 3 4 Hart, William; Beumel, O. F.; Whaley, Thomas (22 October 2013). The Chemistry of Lithium, Sodium, Potassium, Rubidium, Cesium and Francium: Pergamon Texts in Inorganic Chemistry. Online: Pergamon Press. p. 438. ISBN   9781483187570 . Retrieved 31 January 2018.
  3. 1 2 3 4 5 Pistorius, Carl W. F. T. (27 December 1968). "Phase Diagrams to High Pressures of the Univalent Azides Belonging to the Space Group D 4hI8-14/mcm" (PDF). Online. pp. 1, 4–5. Retrieved 1 February 2018.
  4. 1 2 3 Hála, Jiri. "IUPAC-NIST Solubility Data Series. 79. Alkali and Alkaline Earth Metal Pseudohalides" (PDF). nist.gov. Archived from the original (PDF) on 1 February 2018. Retrieved 31 January 2018.
  5. ↑ Ogden, J. Steven; Dyke, John M.; Levason, William; Ferrante, Francesco; Gagliardi, Laura (2006). "The Characterisation of Molecular Alkali-Metal Azides" (PDF). Chemistry - A European Journal. 12 (13): 3580–3586. doi:10.1002/CHEM.200501101. PMID   16491492. S2CID   16007959. Archived from the original (PDF) on 3 February 2018. Retrieved 2 February 2018.
  6. 1 2 Karlen, Sylvain; Gobet, Jean; Overstolz, Thomas; Haesler, Jacques; Lecomte, Steve (26 January 2017). "Lifetime assessment of RbN3-filled MEMS atomic vapor cells with Al2O3 coating" (PDF). Optics Express. 25 (3): 2187–2194. Bibcode:2017OExpr..25.2187K. doi: 10.1364/OE.25.002187 . PMID   29519066 . Retrieved 17 March 2018.
  7. ↑ H. Wattenberg: "Über zwei Bildungsweisen von Natriumnitrid und Kaliumnitrid" in Ber. d. dt. chem. Ges.1930, 63(7), S. 1667-1672. doi : 10.1002/cber.19300630708
  8. ↑ Babu, K. Ramesh; Vaitheeswaran, G. (2013). "Structure, elastic and dynamical properties of KN3 and RbN3: A van der Waals density functional study". Solid State Sciences. Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad. 23: 17–25. arXiv: 1311.0979 . Bibcode:2013SSSci..23...17R. CiteSeerX   10.1.1.768.1309 . doi:10.1016/j.solidstatesciences.2013.05.017. S2CID   94217260.
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