Niobium chloride

CAS no.:10026-12-7
Molecular formula: Cl5Nb
Molecular weight: 270.173
The density (g/mL, 25 ℃) : 2.75.
Melting point (DCS) : 204.7.
Boiling point (dc, atmospheric pressure) : 250.
Solubility: soluble in water and water reactions.

Structure: solid niobium pentachloride is a dimer containing two chloride Bridges. Each niobium atom is a hexagonal deformation octahedral configuration, with two bridge bond lengths of 256pm, flat bond lengths of 225pm and straight bond lengths of 229.2 PM. Straight key inward deformation, and formation of two chlorine bridge plane Angle is 83.7 °, chlorine bridge of Nb – Cl – Nb bond Angle is 101.3 °. Nb-nb is relatively long at 398.8 PM, not enough to generate metal-to-metal interactions. Similar structures such as niobium pentabromide, tantalum pentaboride and tantalum pentabromide are also adopted. Niobium pentachloride is monomeric in the gas phase.

Molecular structural data:
Molar index of refraction: unusable
Molar volume (cm3/mol) : unusable
Isozhang specific volume (90.2k) : unusable
Surface tension (dyne/cm) : useless
Dielectric constant: useless
Polarization rate (10-24cm3) : useless
Single isotope mass: 267.750664 Da
Nominal quality: 268 Da
Average mass: 270.1714 Da
The synthetic methods:
The sample boat with 10g of niobium powder was put into the borosilicate glass reaction tube with internal diameter of 25mm and length of 900mm. Make chlorine gas at the rate of about 200 ml/min flow into the reaction tube at the same time, the part sample heated to 300 ℃ or so, the five niobium chloride yellow crystalline precipitate at room temperature in the reactor vessel part. The gas is absorbed completely in a chlorine absorber (a mixture of sodium hydroxide and sodium bicarbonate). Reaction after cooling, with rare gas displacement chlorine gas, and a rare gas in the air out of five niobium chloride, or niobium chloride precipitation reaction tube (Ⅴ) parts of the sealing ends (in this case, should be made in the reaction tube diameter of 10 mm neck). In addition, niobium pentoxide and six times the molar ratio of coal blending, to the sample dissolved into the flow of 200 ~ 300 ml/min of chlorine, chlorination reaction is carried out under the 500 ~ 700 ℃. Of five niobium chloride and acetone a niobium oxide NbOCl3 mixture, with chlorine gas through the carbon layer heated to 600 ℃, thus also five niobium chloride can be obtained.
Dangerous sign: C: Corrosive;
Risk terms: R22:Harmful if swallowed. R34: Causes burns.;