

Dreiding Model Exchange
The Dreiding Models
 In the late 1950ies, Andre S. Dreiding introduced a stainless steel molecular modeling kit, in which atoms have solid and hollow valence spikes. The solid rods clicked into the tubes, thus forming a bond, usually with free rotation. The models' accuracy allowed measurements of interatomic distances with a ruler.
Model Sets
 The Dreiding models were sold by Buechi (Switzerland) in Europe, and by Aldrich in North America, and are very widely used in organic and natural products chemistry.
 The models typically came as sets, as described in Aldrich's Technical Bulletin AL199 (PDF description) and in the 1964 bulletin of the ILbased SWISSCO, a distributor of the Dreiding models
 A detailed description of the Dreiding models was published by Buechi (Switzerland) in 1966 in the form of the 2nd edition of a List of All Available Model Units.
 A very comprehensive description and listing of model parts and properties was published by Sybron/Brinkmann under the title Dreiding Stereomodels (BR 297D)
Dreiding Model Exchange
 In 2010, a Dreiding Model Exchange for academic purposes was established at College of Pharmacy at the University of Illinois at Chicago, Chicago (IL)
 If you have such models available or would like to obtain additional model parts to extend your own collection, please send a list of atom types, numbers, etc. and your intent to exchange/sell/buy to dreidingexchange@gmail.com
Contact Information:
Jim McAlpine Ph.D.
Guido Pauli Ph.D.
Dreiding Model Exchange
Department of Medicinal Chemistry and Pharmacognosy
College of Pharmacy
University of Illinois at Chicago
833 S. Wood St.Chicago , IL 60612
Further Resources
In memoriam Andre S. Dreiding (19192013)
The following publication has been published in the Journal of Mathematical Chemistry in memoriam of Dr. Dreiding, a pioneer in mathematical chemistry:
 Wirth, K.; Dreiding, A. S.
Relations between edge lengths, dihedral and solid angles in tetrahedra.
Journal of Mathematical Chemistry 2014, 52, 16241638.
 Abstract: "The tetrahedron, fundamental in organic chemistry, is examined in view of two important kinds of angles: to each tetrahedron edge belongs a dihedral angle (internal intersection angle between two faces having the edge as common side) and to each tetrahedron vertex a solid angle (area of the surface inside the tetrahedron on the unit sphere with the vertex as center). Based on preliminary lemmas, these angles are expressed in terms of edge lengths by an essential use of determinants. The resulting formulae enable to specify angle properties by edge lengths, especially with regard to equality and inequality of single solid angles or certain sums of dihedral angles. A special kind of equal solid angles leads to symmetry aspects. Finally, it is shown that by a particular rearrangement of edges in tetrahedra of a specific class some derived angle properties will be preserved."
 The frontpage footnotes provides background information:
"
André S. Dreiding, Professor Emeritus at the University of Zürich, deceased on December 24, 2013, at the age of 94. He was a pioneer in the field of mathematical chemistry. The Dreiding Stereomodels, invented in 1958 and used worlwide for around 40 years, are essentially characterized by geometrical ideas. Apart from his main activity in organic chemistry (i.a. elucidation of natural products, biosynthesic paths, totalsyntheses), André S. Dreiding started an interdisciplinary project in 1970 with the aim to systemize molecular model concepts in order to enable computer implementations (see for instance [3, 9]). In his last years, as long as his health allowed it, he was involved in problems of mathematical chemistry [10–12]."
