Properties

 

Boiling Point

113.5 °C

@ 1 atm

Freezing Point

2.0 °C

@ 1 atm

Density

1.004 g ml -1

@ 25 °C

Viscosity

0.90 cp

@ 25 °C

pKa of cation

8.07

.

Dielectric constant

52

@ 25 °C

Molar Mass

32.04524(7) g mol -1

.

 

At 25 °C hydrazine is 100% in the gauche form (see below), and has the following dimensions:
 
 
 
 

N-N bond length = 1.47 Å 

Bond angle <NNH = 112° 

Hydrazine is a clear, colourless and very hydroscopic liquid at room temperature. It has an ammonia like odour and is a highly polar solvent. Anhydrous hydrazine is a very strong reducing agent. Hydrazine is a very reactive molecule, which can decompose at incredible speed, very exothermically, which makes it ideal as a rocket fuel. Hydrazines are reasonably stable to storage if protected from air although the smaller hydrazines are very flammable.

 The boiling point of monosubstituted hydrazines are higher than that of the corresponding primary amine of the same molecular weight, and even the tetra substituted hydrazines boil at higher temperatures than the analogous hydrocarbon. This is due to hydrogen bonding, which gets increasingly weaker as the hydrazine becomes more substituted.

The basicity of the hydrazines is less than that of similar amines, and the basicity decreases with increasing alkyl substitution. This is in contrast to that of amines where electron donating alkyl groups make the nitrogen more electron rich, and hence the lone electron pair is more available, increasing basisity.

Hydrazine is also a toxic chemical. It is very destructive to skin tissue and the eyes. It is also readily absorbed into the bloodstream where it can cause damage to the liver, the kidneys, the nervous system and the red blood cells. It is also a possible human carcinogen.