Boron compounds: pentaborane (9)

boron symbol icon

The boron in pentaborane (9) formally is in the oxidation state .

Pentaborane (9)

  • Formula as often written: B5H9
  • Hill system formula: B5H9
  • CAS registry number: [19624-22-7]
  • Formula weight: 63.126
  • Class: hydride


  • pentaborane (9)
  • boron hydride
  • pentaborane (9)
  • pentaboron nonahydride

Physical properties

  • Colour: colourless
  • Appearance: liquid
  • Melting point: -47°C
  • Boiling point: 60°C
  • Density: 600 kg m-3 (liquid)


Coming soon...

Element analysis

Element percentages for the elements in pentaborane (9)
Element %
B 85.63
H 14.37


Not available

Isotope pattern

What follows is the calculated isotope pattern for the B5H9 unit with the most intense ion set to 100%.

Formula: B5H9

mass  %
59   0.1 
60 1.5 _
61 12.4 ______
62 49.7 _________________________
63 100.0 __________________________________________________
64 80.6 ________________________________________
65 0.1


The data on these compounds pages are assembled and adapted from the primary literature and several other sources including the following.

  • R.T. Sanderson in Chemical Periodicity, Reinhold, New York, USA, 1960.
  • N.N. Greenwood and A. Earnshaw in Chemistry of the Elements, 2nd edition, Butterworth, UK, 1997.
  • F.A. Cotton, G. Wilkinson, C.A. Murillo, and M. Bochmann, in Advanced Inorganic Chemistry, John Wiley & Sons, 1999.
  • A.F. Trotman-Dickenson, (ed.) in Comprehensive Inorganic Chemistry, Pergamon, Oxford, UK, 1973.
  • R.W.G. Wyckoff, in Crystal Structures, volume 1, Interscience, John Wiley & Sons, 1963.
  • A.R.West in Basic solid state chemistry Chemistry, John Wiley & Sons, 1999.
  • A.F. Wells in Structural inorganic chemistry, 4th edition, Oxford, UK, 1975.
  • J.D.H. Donnay, (ed.) in Crystal data determinative tables, ACA monograph number 5, American Crystallographic Association, USA, 1963.
  • D.R. Lide, (ed.) in Chemical Rubber Company handbook of chemistry and physics, CRC Press, Boca Raton, Florida, USA, 77th edition, 1996.
  • J.W. Mellor in A comprehensive treatise on inorganic and theoretical chemistry, volumes 1-16, Longmans, London, UK, 1922-1937.
  • J.E. Macintyre (ed.) in Dictionary of inorganic compounds, volumes 1-3, Chapman & Hall, London, UK, 1992.

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boron atomic number