Niobium oxychloride is the

inorganic compound 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 chemist ...

with the formula NbOCl₃. It is a white, crystalline, diamagnetic

solid Solid is one of the State of matter#Four fundamental states, four fundamental states of matter (the others being liquid, gas, and Plasma (physics), plasma). The molecules in a solid are closely packed together and contain the least amount o ...

. It is often found as an impurity in samples of

niobium pentachloride Niobium(V) chloride, also known as niobium pentachloride, is a yellow crystalline solid. It hydrolyzes in air, and samples are often contaminated with small amounts of NbOCl3. It is often used as a precursor to other compounds of niobium. NbC ...

, a common

reagent In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...

in niobium chemistry.

Structure

In the solid state the

coordination sphere In coordination chemistry, the first coordination sphere refers to the array of molecules and ions (the ligands) directly attached to the central metal atom. The second coordination sphere consists of molecules and ions that attached in various ...

for niobium is a distorted

octahedron In geometry, an octahedron (plural: octahedra, octahedrons) is a polyhedron with eight faces. The term is most commonly used to refer to the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at ea ...

. The Nb–O bonds and Nb–Cl bonds are unequal. This structure can be described as planar Nb₂Cl₆ core connected by O–Nb–O bridges. In this way, the compound is best described as a polymer, consisting of a double stranded chain. In the gas phase above 320 °C the

Raman spectrum Raman spectroscopy () (named after Indian physicist C. V. Raman) is a Spectroscopy, spectroscopic technique typically used to determine vibrational modes of Molecule, molecules, although rotational and other low-frequency modes of systems may als ...

is consistent with a

pyramidal A pyramid (from el, πυραμίς ') is a structure whose outer surfaces are triangular and converge to a single step at the top, making the shape roughly a pyramid in the geometric sense. The base of a pyramid can be trilateral, quadrilater ...

monomer containing a niobium–oxygen

double bond In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist betw ...

Synthesis

Niobium oxychloride is prepared by treating the pentachloride with oxygen: :NbCl₅ + O₂ → NbOCl₃ + Cl₂ This reaction is conducted at about 200 °C. NbOCl₃ also forms as a major side-product in the reaction of

niobium pentoxide Niobium pentoxide is the inorganic compound with the formula Nb2 O5. A colorless, insoluble, and fairly unreactive solid, it is the most widespread precursor for other compounds and materials containing niobium. It is predominantly used in alloyi ...

with various chlorinating agents such as

carbon tetrachloride Carbon tetrachloride, also known by many other names (such as tetrachloromethane, also IUPAC nomenclature of inorganic chemistry, recognised by the IUPAC, carbon tet in the cleaning industry, Halon-104 in firefighting, and Refrigerant-10 in HVAC ...

and

thionyl chloride Thionyl chloride is an inorganic compound with the chemical formula . It is a moderately volatile, colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a chlorinating reagent, with approximately per year bein ...

.. :2 Nb₂O₅ + 6 CCl₄ → 4 NbOCl₃ + 6 COCl₂

References

{{Niobium compounds Niobium(V) compounds Chlorides Metal halides Oxychlorides