Rare Vintage Steel BUCHI DREIDING STEREOMODELS in Case over 300 Pieces EUC

Description

Rare Vintage Steel  BUCHI DREIDING  STEREOMODELS in Case over 300  Pieces EUC
2 level case
you will receive exactly what is pictured
Dreiding Stereomodels
In 1958, Dreiding invented a
molecular model
used primarily in
stereochemistry
, named the
Dreiding Stereomodel
. It was a so-called
skeletal model
, which consisted of slim stainless steel tubes and rods. Unlike the older
ball-and-stick models
, the atoms were not represented by a ball, but rather by the point of intersection of the steel tubes. The intersection area was painted with a color to indicate the identity of the atom. As the tubes represented the bonds, the model focused on the geometry of the bonds between atoms rather than the atoms themselves. The Dreiding Stereomodel was not the first skeletal model, but was the first to do away with the connectors that had been used in e.g.
John Kendrew
's earlier
protein
models. Instead, the Dreiding Stereomodels used a valency of the bonds/steel tubes to facilitate connections; they were either a hollow tube or a slightly narrower solid rod, which fit into the tube. A tube not connected to another tube represented a
hydrogen
atom, and the bond from the other atom (for example
carbon
,
oxygen
or
nitrogen
) to the hydrogen atoms. This gave the Dreiding Stereomodels a very neat look, and made the assembly much quicker than for earlier skeletal models. They were also quite precise in representing the molecular geometry, so they could be used to determine inter-atomic distances and angles by rulers.
Availability of Dreiding Stereomodels
The Dreiding Stereomodels were primarily used as a research tool rather than an educational tool for undergraduates. They were widely used by organic chemists, stereochemists and natural products chemists in universities and other research laboratories. The models were sold by
Büchi
in Europe and by
Aldrich
in North America. A simpler and cheaper plastic version was later introduced intended for educational purposes, but never became as widely spread as the original steel version. When molecular modeling software became more readily available in the 1990s, the use of Dreiding Stereomodels declined and production stopped, and the models were apparently discontinued around 2005. However, especially for the purposes of spectroscopic structure elucidation using NMR and MS, the availability of "hands-on" accurate molecular models continues to be very valuable. E.g., in natural products chemistry, where structures are often elucidated ab initio, Dreiding Stereomodels can be extremely useful as they allow the rapid assembly of alternative and closely related structures with high geometric precision (e.g., for NOE or 2D NMR interpretations). Because of their widespread use and availability for >40 years, many researchers and departments still maintain and use their collections. In order to ameliorate the general supply problem for spare parts or entire models, the
Dreiding Model Exchange
was established in 2010 at the University of Illinois at Chicago.
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This item itself comes exactly as pictured; nothing more, nothing less. I try very hard to totally inspect each item carefully and write descriptions accordingly  and I take great care to fully photograph the entire item in its exact condition. No stock photos are used. the item or items as described will ship exactly as it is presented. Buyer should fully review the photos attached to this listing to ensure that Buyer expectations concerning the listed item are met. If the item is used, it will often show signs of use, general wear and tear, small dents or scratches,dust  etc
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WHITE SPOTS OR STREAKS ARE REFLECTIONS AND GLARE FROM THE LIGHTING.
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Used: An item that has been used previously. The item may have some signs of cosmetic wear, but is fully operational and functions as intended unless described differently in the description . See listing for full details and description of any noted imperfections.
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