Associates / Fellows
Karl O. Christe
Research Professor of Chemistry
Our interests are very broad and range from very basic studies to applied research
of academic, Government or industrial interest. We are particularly interested
in high energy density materials (HEDM), inorganic main group chemistry, polynitrogen
and nitramine chemistry, high-oxygen carriers, energetic ionic liquids, chemistry
at the limits of oxidation and coordination, and the synthesis and characterization
of novel carbocation and fluorocarbon compounds. Our work exploits the synergism
of theory and synthesis and greatly benefits from close collaborations with
numerous groups of theoreticians. The main goal of our research is to advance
the state of the art and strive for spectacular break-throughs, rather than
settling for small incremental improvements.
Typical examples of break-through achievements, achieved by us in the past,
include the first syntheses of novel cations, such as NF4+  or ClF6+ , which are derived from nonexisting parent
molecules, the first chemical synthesis of elemental fluorine  which according
to the textbooks was impossible, the synthesis of XeF5-  and IF52  which constitute the first examples of
pentagonal planar AX5 species, the development of a synthesis for truly anhydrous
soluble "naked" fluoride ion  which has led to a renaissance in
high coordination number chemistry , the synthesis of N5+  which is the only stable polynitrogen species in more than 100 years and
only the second known man-made polynitrogen preparable on a macroscopic scale,
the spectroscopic identification of the cyclic N5- anion
, the synthesis of the first oxygen-balanced energetic ionic liquids for
liquid monopropellant applications , the preparation and characterization
of over 40 new polyazides  and their combination with energetic counter-ions
as for example in [N5]+[B(N3)4]- , and the developments of the first quantitative scales for oxidizer strengths
 and Lewis acidities .
"The Tetrafluoronitronium (V) Cation, NF4+," K.
O. Christe, J.P. Guertin, and A.E. Pavlath, Inorg. Nucl. Chem. Letters, 2, 83 (1966).
|| "The Hexafluorochlorine (VII) Cation, ClF6+," K. O.
Christe, Inorg. Nucl. Chem. Letters, 8, 741 (1972).
|| "Chemical Synthesis of Elemental Fluorine," K. O. Christe, Inorg. Chem., 25, 3721 (1986).
|| "The Pentafluoroxenate (IV) Anion, XeF5-; the First
Example of a Pentagonal Planar AX5 Species," K. O. Christe, E.
C. Curtis, H.P. Mercier, J. C. P. Sanders, G. J. Schrobilgen, and D. Dixon, J. Am. Chem. Soc., 113, 3351 (1991).
|| "Pentagonal Planar AX5 Species: Synthesis and Characterization
of the Iodine (III) Pentafluoride Dianion, IF52-,"
K. O. Christe, W.W. Wilson, G.W. Drake, D.A. Dixon, J.A. Boatz, and R.Z.
Gnann, J. Am. Chem. Soc., 120, 4711 (1998).
|| "Syntheses, Properties, and Structures of Anhydrous Tetramethylammonium
Fluoride and its 1:1 Adduct with trans-3-Amino-2-Butene Nitrile," K. O.
Christe, W. W. Wilson, R. D. Wilson, R. Bau, and J. Feng, J. Am. Chem.
Soc., 112, 7619 (1990).
|| "Heptacoordinated Main-Group Fluorides and Oxyfluorides," K. O. Christe,
E.C. Curtis, D.A. Dixon, H.P.A. Mercier, J.C.P. Sanders, G.J. Schrobilgen,
and W.W. Wilson, Chapter 5 in "Inorganic Fluorine Chemistry Toward the 21st
Century" ACS Symposium Series 555 (1994).
|| "N5+: A Novel Homoleptic Polynitrogen Ion as a High
Energy Density Material," K. O. Christe, W. W. Wilson, J. A. Sheehy, and
J. A. Boatz, Angew. Chem. Int. Ed., 38, 2004 (1999).
|| “Experimental Detection of the Pentaazacyclopentadienide (Pentazolate)
Anion, cyclo-N5-,” A. Vij, J. G. Pavlovich,
W. Wilson, V. Vij, and K. O. Christe, Angew. Chem. Int. Ed., 41,
|| “Oxygen Balanced Energetic Ionic Liquid,” C. J. Bigler Jones,
R. Haiges, T. Schroer, and K. O. Christe. Angew. Chem. Int. Ed., 2006, published
|| “Experimental Evidence for Linear Metal-Azide Bonds. The Binary Group
5 Azides Nb(N3)5, Ta(N3)5, [Nb(N3)6]- and [Ta(N3)6]-, and 1:1 Adducts of Nb(N3)5
and Ta(N3)5 with CH3CN,” R. Haiges,
J. A. Boatz, T. Schroer, M.Yousufuddin, and K. O. Christe, Angew. Chem.
Int. Ed., 45, 4830 (2006) and references cited therein.
|| “New High Energy Density Materials. Synthesis and Characterization
of N5+P(N3)6-, N5+B(N3)4-,
N5+PF6-, and N5+SO3F-,”
R. Haiges, S. Schneider, T. Schroer, and K. O. Christe, Angew. Chem. Int.
Ed., 43, 4919 (2004),.
|| "A Quantitative Scale for the Oxidizing Strength of Oxidative Fluorinators,"
K. O. Christe and D.A. Dixon, J. Am. Chem. Soc., 114, 2978
|| "A Quantitative Scale for Lewis Acidities Based on Absolute Fluoride Ion
Affinities," K. O. Christe, D. A. Dixon, and D. McLemore, J. Am. Chem.
Soc., to be published.|