Zirconium nitrate is a volatile anhydrous transition metal

nitrate Nitrate is a polyatomic ion 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 that is not zer ...

salt of

zirconium Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'', ...

with formula Zr(NO₃)₄. It has alternate names of zirconium tetranitrate, or zirconium(IV) nitrate. It has a UN number of UN 2728 and is class 5.1, meaning oxidising substance.

Formation

The anhydrous salt can be made from

zirconium tetrachloride Zirconium(IV) chloride, also known as zirconium tetrachloride, () is an inorganic compound frequently used as a precursor to other compounds of zirconium. This white high-melting solid hydrolyzes rapidly in humid air. Structure Unlike molecular T ...

reacting with dinitrogen pentoxide. ZrCl₄ + 4 N₂O₅ → Zr(NO₃)₄ + 4ClNO₂ The product can be purified by sublimation in a vacuum. A contaminating substance in this is nitronium pentanitratozirconate. (NO₂)Zr(NO₃)₅. Zirconium nitrate pentahydrate Zr(NO₃)₄·5H₂O can be formed by dissolving

zirconium dioxide Zirconium dioxide (), sometimes known as zirconia (not to be confused with zircon), is a white crystalline oxide of zirconium. Its most naturally occurring form, with a monoclinic crystalline structure, is the mineral baddeleyite. A dopant stabi ...

in nitric acid and then evaporating the solution until it is dry. However it is easier to crystallise zirconyl nitrate trihydrate ZrO(NO₃)₂·3H₂O from such a solution. Zirconium is highly resistant to nitric acid even in the presence of other impurities and high temperatures. So zirconium nitrate is not made by dissolving zirconium metal in nitric acid.

Properties

Zirconium nitrate pentahydrate dissolves easily in water and alcohol. It is acidic in aqueous solution, and a base such as

ammonium hydroxide Ammonia solution, also known as ammonia water, ammonium hydroxide, ammoniacal liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or (inaccurately) ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq). Although ...

will cause zirconium hydroxide to precipitate. The pentahydrate crystals have a refractive index of 1.6.

Related substances

Related substances are zirconium nitrate complexes. has a

tricapped trigonal prismatic In chemistry, the tricapped trigonal prismatic molecular geometry describes the shape of compounds where nine atoms, groups of atoms, or ligands are arranged around a central atom, defining the vertices of a triaugmented triangular prism (a trigo ...

structure, with the nitrates connected by two oxygen atoms each ( bidentate). The pentanitrato complex has all the nitrate groups bidentate, and has a bicapped square antiprism shape. NO₂ r(NO₃)₃·3H₂Osub>2(NO₃)₃ crystallizes in the

hexagonal system In crystallography, the hexagonal crystal family is one of the six crystal families, which includes two crystal systems (hexagonal and trigonal) and two lattice systems (hexagonal and rhombohedral). While commonly confused, the trigonal crystal ...

, space group ''P'c''1, with unit cell dimensions a = 10.292 Å, b = 10.292 Å, c = 14.84 Å, volume 1632.2 Å³ with 2 formulae per unit cell, density = 2.181. CsZr(NO₃)₅ crystallizes in the

monoclinic system In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic s ...

, space group ''P''2₁/''n'', with unit cell dimensions a = 7.497 Å, b = 11.567 Å, c = 14.411 Å, β=96.01°, volume 1242.8 Å³ with 4 formulae per cell, density = 2.855. (NH₄)Zr(NO₃)₅·HNO₃ crystallizes in the

orthorhombic system In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a r ...

, space group ''Pna''2₁ with unit cell dimensions a=14.852 Å, b = 7.222 Å, c = 13.177 Å, volume 1413.6 Å³ with 4 formulae per cell, density = 2.267. A mixed

nitronium The nitronium ion, , is a cation. It is an onium ion because its nitrogen atom has +1 charge, similar to ammonium ion . It is created by the removal of an electron from the paramagnetic nitrogen dioxide molecule , or the protonation of nitric aci ...

nitrosonium The nitrosonium ion is , in which the nitrogen atom is bonded to an oxygen atom with a bond order of 3, and the overall diatomic species bears a positive charge. It can be viewed as nitric oxide with one electron removed. This ion is usually obta ...

pentanitratozirconate crystallizing in the tetragonal system also exists.

Use

Zirconium nitrate is manufactured by a number of chemical suppliers. It is used as a source of zirconium for other salts, as an analytical standard, or as a preservative. Zirconium nitrate and nitronium pentanitratozirconate can be used as chemical vapour deposition precursors as they are volatile, and decompose above 100 °C to form

zirconia Zirconium dioxide (), sometimes known as zirconia (not to be confused with zircon), is a white crystalline oxide of zirconium. Its most naturally occurring form, with a monoclinic crystalline structure, is the mineral baddeleyite. A dopant stabi ...

. At 95 °C, zirconium nitrate sublimes with a pressure of 0.2 mm of Hg and can be deposited as zirconium dioxide on silicon at 285 °C. It has the advantage in that it is a single source, meaning it does not have to be mixed with other materials like oxygen, and decomposes at a relatively low temperature, and does not contaminate the surface with other elements such as hydrogen or fluorine. Zirconium free from hafnium is required for nuclear reactor construction. One way to achieve this is via a mixed aqueous solution of hafnium nitrate and zirconium nitrate, which can be separated by partitioning the zirconium into

tributylphosphate Tributyl phosphate, known commonly as TBP, is an organophosphorus compound with the chemical formula (CH3CH2CH2CH2O)3PO. This colourless, odorless liquid finds some applications as an extractant and a plasticizer. It is an ester of phosphoric aci ...

dissolved in kerosene. Zirconium nitrate can be used as a Lewis acid catalyst in the formation of N-substituted

pyrroles Pyrrole is a heterocyclic aromatic organic compound, a five-membered ring with the formula C4 H4 NH. It is a colorless volatile liquid that darkens readily upon exposure to air. Substituted derivatives are also called pyrroles, e.g., ''N''-methy ...

. registration required Anhydrous zirconium nitrate can nitrate some organic aromatic compounds in an unusual way. Quinoline is nitrated to 3-nitroquinoline and 7-nitroquinoline.

Pyridine Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid with a d ...

is nitrated to 3-nitropyridine and 4-nitropyridine.

References

{{zirconium compounds Zirconium(IV) compounds Nitrates