Niob(V)-chlorid Chemische Eigenschaften,Einsatz,Produktion Methoden
R-Sätze Betriebsanweisung:
R20/21/22:Gesundheitsschädlich beim Einatmen,Verschlucken und Berührung mit der Haut.
R34:Verursacht Verätzungen.
S-Sätze Betriebsanweisung:
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S27:Beschmutzte, getränkte Kleidung sofort ausziehen.
S28:Bei Berührung mit der Haut sofort abwaschen mit viel . . . (vom Hersteller anzugeben).
S36/37/39:Bei der Arbeit geeignete Schutzkleidung,Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
Chemische Eigenschaften
yellow fine crystalline powder
Physikalische Eigenschaften
Yellow monoclinic crystals; deliquesces; density 2.75 g/cm
3; decomposes in moist air with the evolution of HCl; melts at 204.7°C; vaporizes at 254°C; decomposes in water; soluble in alcohol, hydrochloric acid, chloroform and carbon tetrachloride.
Verwenden
Niobium(V) chloride is the precursor in the preparation of pure niobium, and ferroniobium. It is used as a Lewis acid catalyst in organic synthesis in activating alkenes in the carbonyl-ene reaction and the Diels-Alder reaction.
synthetische
Niobium pentachloride is obtained as an intermediate during extraction of niobium from its ores (see Niobium). Also, the pentachloride is obtained readily by direct chlorination of niobium metal at 300 to 350°C: 2Nb + 5Cl
2 → 2NbCl
5The pentachloride also may be made by chlorination of niobium pentoxide in the presence of carbon at 300°C. The products, however, contain small amounts of niobium oxide trichloride, NbOCl
3.
Hazard
May evolve fumes of hydrogen chloride.
Keep dry
Sicherheitsprofil
Poison by
intraperitoneal route. Moderately toxic by
ingestion. May cause kidney injury. When
heated to decomposition it emits very toxic
fumes of Cl-. See also NIOBIUM and
CHLORIDES.
läuterung methode
It forms yellow, very deliquescent crystals which decompose in moist air to liberate HCl. It should be kept in a dry box flushed with N2 in the presence of P2O5. Wash it with CCl4 and dry it over P2O5. The yellow crystals usually contain a few small, dirty white pellets among the yellow needles. These should be easily picked out. Upon grinding in a dry box, however, they turn yellow. NbCl5 has been sublimed and fractionated in an electric furnace. [Epperson Inorg Synth VII 163 1963, Alexander & Fairbrother J Chem Soc suppl 233 1949.] d2 5 20 pK25
Niob(V)-chlorid Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
