Three-dimensional molecular models are modules made of plastic, for example, and connected to one another. Such modules can be made as hemispheres, cut-off spheres or polyhedrons. Each module represents an atom. The radius of a hemisphere represents the Van der waals atomic radius, while the distance from the center of the sphere to the cut-off plane is the covalent atomic radius. Connecting members of modules represent interatomic bonds while the angles between their geometric axes are valency angles. Conformal displacement of atoms is represented by turning individual modules or whole sets about connecting members.
Known in the art is a three-dimensional molecular model comprising hollow plastic modules made as hemispheres, cut-off spheres or polyhedrons. Each module is provided with one or several openings to fit conical elements of connecting members (cf., for example, U.S. Pat. No. 3,170,246 C1. 35-18, 1965).
Also known in the art is a three-dimensional molecular model comprising plastic modules each representing one atom of a molecular structure. Modules are joined together by connecting members fitted into sockets of the modules. Plastic modules designed to represent atoms of cyclic compounds are made as regular polyhedrons whose faces are adjacent so that the model has one common apex (cf., for example, advertising booklet of the Ealing Corporation, South Natick, Mass., CPK Precision Molecular Models, 1980, pp. 27 and 30).
The above known three-dimensional molecular models are deficient in that they can represent only planar cyclic compounds. This is conditioned by the fact that, when models of cyclic compounds are put together, the centers of modules are located in one plane, which can be conditionally referred to as the cycle plane, and the sum of the angles formed by adjoining faces of the polyhedrons is equal to or less than 360.degree., so that a single atom or several atoms cannot be brought out of the cycle plane.