US3509642A - Semi-skeletal molecular model assembly - Google Patents

Description

y 1970 G. c. BRUMLIK 3,509,642

SEMI-SKELETAL MOLECULAR MODEL ASSEMBLY Filed Sept. 13, 196'? 4 Sheets-Sheet 1 ATTORNEY May 5, 1970 G. c. BRUMLIK SEMI-SKELETAL MOLECULAR MODEL ASSEMBLY 4 Sheets- Sheet 2 Filed Sept. 13, 1967 FlG.

ATTORN EY May 5, 1970 s. QBRUMLIK 3,509,642

SEMI-SKELETAL MOLECULAR MODEL ASSEMBLY Filed Sept. 13, 1967 4 Sheets-Sheet 5 INVENTOR. GEORGE C. BROMLI K ATTORNEY y 5, 1970 G. c. BRUMLIK 3,509,642

SEMI-SKELETAL MOLECULAR MODEL ASSEMBLY v Filed Sept. 13, 1967 4 Sheets-Sheet 4 INVENTOR. GEORGE c. BRUMLIK ATTORNEY United States Patent 0 M 3,509,642 SEMI-SKELETAL MOLECULAR MODEL ASSEMBLY George C. Brumlik, 154 Upper Mountain Ave., Montclair, NJ. 07042 Filed Sept. 13, 1967, Ser. No. 667,581 Int. Cl. G09b 23/26 US. Cl. 35-18 8 Claims ABSTRACT OF THE DISCLOSURE A molecular model assembly including a plurailty of units representing atom cores and having solid bodies formed as tetrahedrons, trigonal bipyramids and octahedrons, with a bore formed at each corner of each body and arranged in accordance with the symmetry axes of valence orbitals and bond angles of the atom to be depicted by the body. A plurality of elongated rods are also provided for interconnecting the atom core units to form semi-skeletal models of selected molecules, and the assembly also includes spherical bodies representing terminal atoms, ellipsoid bodies representing orbital lobes, and bodies of bulbous, eccentric shape representing antibonding orbital lobes, these bodies being adapted to be mounted on the interconnected atom core bodies to complete the assembled molecular model.

The present invention relates to model assemblies used to represent atoms and molecules, particularly models representing the physical and geometric relationships of molecular and atomic orbitals.

In my prior US. Patent No. 3,080,662 issued Mar. 12, 1963, I have shown and described a molecular model assembly in which the atoms were depicted by solid spherical elements having appropriately located openings frictionally reciving pins by means of which these elements were interconnected. These openings are positioned and directed in accordance with the orientation of the symmetry axes and the symmetry planes of atomic and molecular orbitals. The atoms and their orbitals are depicted in the models of this patent in three dimensional form, and the models can be designated as space-filling."

In another US. Patent No. 3,333,349 issued Aug. 1, 1967, I have shown and described a molecular model assembly in which the atoms and their orbitals are represented in open framework form. In particular, the atoms are represented as valence clusters by the use of multiarm coupling units having arm sections angularly arranged to represent the symmetry axes of atomic valence orbitals and bond angles.

While the models assembled by the structures disclosed in the aforementioned patents provide an accurate representation of the characteristic shapes, volumes and spacial orientation of atomic and molecular orbitals in accordance with modern theories of valence, they lack a garphic depiction of the atoms insofar as their symmetry axes and planes are concerned, which visual representation may be of great use to the student. The aforementioned framework model depicts the atom only as a valence cluster. The space-filling model depicts the atom as a sphere, which, while in accordance with prevailing theory, does not illustrate the symmetry planes.

It is an object of the present invention to provide molecular orbital models in which the atoms are made in the form of polyhedrons to depict the tetrahedron, trigonal bipyramid and octahedron patterns constituting the three basic forms of angles for virtually all atoms.

Another object of the invention is the provision of molecular orbital models in which the solid atoms in polyhedron form are coupled by framework connectors 3,509,642 Patented May 5, 1970 to provide a semi-skeletal type model presenting a more apparent visual indication of the state of centers of the atoms and their states of hybridization.

Still another object of the invention is the provision of molecular orbital models of the character described in which the molecules can be shown not only in a static state but in an excited state, and the relative motions of atoms within a molecule can be depicted.

In accordance with the invention there is provided a model assembly for representing the atomic and molecular orbital structure of atoms in a molecule, which assembly includes a plurality of units representing atom cores and each constituting a solid body having the form of a tetrahedron, trigonal bipyramid or octahedron, with a bore at each corner thereof arranged in accordance with the symmetry axes of valence orbitals and bond angles of the atom to be depicted by the unit. The assembly also includes a plurality of units representing atomic orbital lobes, each of which units comprises a hollow body of generally ellipsoid shape having a terminal bore, as well as a plurality of hollow spherical units representing terminal atoms. In addition, the assembly includes coupling means in the form of elongated members having end portions sized to fit frictionally within the bores of the atom core units and orbital lobe units for interconnecting selected atom core units and for connecting selected orbital lobe units and spherical terminal atom units to said atom core units to form semi-skeletal models of selected molecules.

Additional objects and advantages of the invention will become apparent during the course of the following specification when taken in connection with the accompanying drawings, in which:

FIGS. 1, 2 and 3 respectively are perspective views of three different embodiments of atom core bodies employed in the models of this invention;

FIGS. 4, 5 and 6 respectively are elevational views of three dilferent sizes of hexagonal coupling rods which may be employed to interconnect the core bodies to each other or to orbital lobe bodies;

FIG. 7 is an elevational view, partially broken way, of a flexible coupling rod which may be employed in the model assembly;

FIG. 8 is an exploded elevational view of another form of coupling rod assembly which may be employed for interconnecting the core bodies to each other or to orbital lobe bodies;

FIG. 9 is a perspective view of an alternate form of the tetrahedron core body shown in FIG. 1;

FIG. 10 is an isometric view showing two of the core bodies of FIG. 1 coupled together to depict two carbon atoms in a single bond;

FIG. 11 is an isometric view of an assembled model depicting the framework of the three carbon atom cyclopropane ring;

FIG. 12 is an isometric view of an assembled model depicting an ethane molecule and including spherical terminal bodies;

FIG. 13 is an enlarged cross sectional view of one of the spherical elements depicting a terminal atom body, as taken along line 1313 of FIG. 12;

FIG. 14 is an isometric view of a space-filling element representing an orbital lobe;

FIG. 15 is an isometric View of an assembled model depicting a benzene ring with a ground state molecular orbital;

FIG. 16 is an isometric view of an assembled model depicting a benzene ring with an excited molecular state orbital;

FIG. 17 is an isometric view of a space-filling model element depicting the lobe of an anti-bonding orbital; and

FIG. 18 is an isometric view of an assembled model of ethylene having anti-bonding orbital lobes.

Referring in detail to the drawings and particularly to FIGS. 1-3, there is shown a series of three different shapes of covalent core bodies 20, 22 and 24 which are employed to depict bonding atoms in the molecular models of the present invention. All three bodies 20, 22 and 24 are formed in the shapes of polyhedrons and may be molded of plastic elastomer or other suitable material.

The core body 20, shown in FIG. 1, is in the form of a tetrahedron and has bores 26 formed at each of its corners and extending toward the center of the body, to provide an sp. tetrahedral pattern representing the symmetry axes of the atomic valence orbitals of a representative atom.

The core body 22, shown in FIG. 2, is in the form of a trigonal bipyramid, and is also provided with centrally-extending bores 28 in each of its corners, providing a trigonal bipyramid pattern representing the symmetry axes of the atomic valence orbitals of an atom having sp. or d.sp. hybridization.

The core body 24, illustrated in FIG. 3, is in the form of an octahedron, and is again provided with centrallyextending bores 30 at each of its corners to represent the octahedral pattern of the symmetry axes of atomic valence orbitals of an atom having sp. or df sp. hybridization.

The core bodies 20, 22 and 24 thus represent the threedimensional bodies of bonding atoms, while their respective bores 26, 28 and 30 represent the angular orientation of the atomic valence orbitals in space. The planar faces of these polyhedron core bodies, terminating at finite corners, give an instant and graphic representation of the symmetry angles and planes of the particular atom when viewed within an assembled model. It will be appreciated that all three bodies 20, 22 and 24 have equilateral triangular faces of the same size, which is desirable and important for purposes of instruction.

The purpose of the bores 26, 28 and 30 is to receive one end of a coupling rod such as the rod 32 shown in FIG. 4. This rod 32 has a relatively short central shank 34 of hexagonal cross-section, which terminates at both ends in cylindrical sections 36 of reduced diameter. The reduced cylindrical end sections 36 are sized for frictional insertion within the bores 26, 28 and 30 of the respective core bodies 20, 22 and 24, the elastomeric nature of the bodies providing tight gripping engagement upon these end sections. Thus, one end section of the coupling rod 32 may be firmly but removably mounted with the bore of one core body and its other end similarly mounted in a bore of another core body for assembling two bodies in position to represent a molecule or a portion thereof. The shank 34 is made of hexagonal shape to provide an effective finger grip whereby the coupling rod may be twisted for mounting and removing the same from the core bodies. In addition, the shank is made relatively short to depict a triple bond distance.

FIG. shows a coupling rod 38, which is identical to the rod 32 of FIG. 4, except that its hexagonal central shank 40 is of greater length to represent the greater bond distance characteristic of a double bond.

FIG. 6 illustrates another coupling rod 42 which is identical to the rods 32 and 38 except that its hexagonal central shank 44 is still longer, representing the even greater bond distance of a single bond.

The coupling rod 46 illustrated in FIG. 7 differs from those previously described in that its shank 48 is flexible and can be bent to depict a dynamic rather than a static model in which various relative motions of atoms within a molecule are shown. Then bending of such coupling rod may also be employed to illustrate stretching of bonds, as well as the phenomenon known as scissoring wherein two atoms move together and pass each other. To afford such bending capabilities, the shank 48 is made in the form of a tightly-coiled spring terminating in cylindrical sec ion 50 identical to the s c ons 36 pre io y escribed in that they are sized for insertion within the bores of the core bodies shown in FIGS. 1-3.

FIG. 8 illustrates a modified type of coupling which may be employed in the assembly of the core bodies into models. In this instance the coupling member comprises a pair of metal elements 52 and a length of plastic tubing 54. Each metal element 52 is formed of a pin 56 having a flange or disc 58 integrally formed at its center. The pin 56 is so sized that one end thereof may be frictionally inserted into a bore 26, 28 or 30 of one of the core bodies of FIGS. l-3, until the flange 58 engages the end of the bore and prevents further insertion. The opposite end of the pin 56 now projects from the corner of the core body, and the length of plastic tubing 54 can now be inserted and frictionally retained upon this projecting end. Thus, where the pair of coupling members are inserted into two respective core bodies, they may be joined by the length of plastic tubing 54, which may be cut to appropriate size to represent the bond in exact scale. The tubing may be made of a flexible plastic to permit bending in the manner of the coupling rod 46 shown in FIG. 7.

Another manner in which coupling of the core bodies may be accomplished is shown in FIG. 9, wherein a tetrahedron core body 20a, corresponding to the core body 20 of FIG. 1, is illustrated by way of example. In this instance, the core body 2011 is formed with a metal or plastic pin 60 fixedly molded Within each of the bores at the corners of the core body, or integrally molded as a projection of the core body. The pins 60 thus project from each corner of the body along respective axes which pass through the central point of the body, thus extending in directions representing the symmetry axes of the atomic valence orbitals. The projecting pins 60 of different core bodies may be coupled together by lengths of plastic tubing 62 similar to the tubing lengths 54 of FIG. 8. The tubing 62 is preferably made of elastomeric plastic, and may be cut to appropriate size depending upon the type of bond to be depicted.

FIG. 10 shows an assembled model consisting of tWo core bodies 20 of tetrahedron shape with a coupling rod 42 of the type shown in FIG. 6 inserted within a core of each body, in the manner previously described. The model thus may represent two bonded carbon atoms, with the coupling rod 42 representing the direction and scale length of a single bond.

FIG. 11 illustrates a model representing a cyclopropane carbon skeleton. In this model, a carbon ring is formed of three of the core bodies 20 arranged in a circular pattern and interconnected by flexible coupling rods 46 in the manner shown. The coupling rods 46 are bent to form the carbon ring, and it will be appreciated that the elastomeric plastic tubes 54 or 62 of FIGS. 8 and 9 may be also employed with their corresponding fastening elements to serve the same purpose.

While the core bodies shown in FIGS. 1-3 and previously described, are provided to represent the central interconnected atoms of molecules, the geometric shapes thereof are not significant in the depiction of terminal atoms of molecules. Consequently, different elements are provided for representing such terminal atoms, these having contrasting shapes to visually distinguish from the central atoms. By way of illustration, FIG. 12 shows a model representing a molecule of ethane and including two central carbon atoms having core bodies 20 of tetrahedron shape connected by a coupling rod 42. The model also includes six core bodies 64 representing terminal hydrogen atoms. The bodies 64 are made of spherical shape as shown, and are preferably molded in hollow form as shown in the sectional view of FIG. 13. Each spherical core body 64 is formed with an integral tubular neck 66 defining a through bore 68 sized for frictional mounting on the end of a coupling pin 70. The pins 70 are sized for insertion into and frictional retention within the appropriate bores 26 of the central core bodies 20. The spherical core bodies 64 are made hollow so as to be light in weight, whereby a number of these terminal bodies may be mounted on a single central body without undue stress. In addition, while the spherical shape illustrated is chosen to distinguish the terminal atoms from the central atoms, the terminal atoms may be made of other selected shapes, for example spheroconical shapes to represent more accurately the actual shape of the atoms.

The models shown herein are also adapted to include representation of volume orbitals in the nature of orbital lobes which protrude from the covalent cores and contribute to the atomic volume beyond the volume of said cores. Such orbital lobes exist where an atom is unsaturated or has non-bonding valence electrons, and assume characteristic shapes, volumes and spacial orientations. In FIG. 14, a hollow body 66 is shown depicting an unshared electron pair orbital. The body 66 is of ellipsoid shape to represent generally the geometric shape of the orbital lobe in accordance with prevailing theories, and is formed with a tubular neck 74 having a through bore 76 sized to frictionally receive an end of one of the Coupling pins 70 so that the lobe body 66 may be mounted upon one of the atom core bodies.

FIG. 15 illustrates the use of a plurality of the orbital lobe bodies 72 in an assembled model. The model shown depicts a benzene ring and is formed of six trigonal bipyramid core boodies 22 interconnected by a corresponding number of coupling rods 42, representing sigma bonds, and arranged in the form of a hexagon. Each n core body 22, representing a carbon atom, has mounted at the top thereof a lobe body 72 by means of a respective coupling pin 70 inserted in the bore 28 of the top corner. Similarly, each core body 22 also has mounted at the bottom corner thereof a lobe body 72a which is identical in size and shape to the lobe body 72 except that it is differently colored or shaded. The upper group of lobe bodies 72 schematically represent an overlap of atomic orbitals to indicate the formation of a single upper orbital streamer which in theory is annular. Similarly, the lower group of lobe bodies 72a indicate the formation of a continuous lower orbital streamer. Thus all of the upper lobe bodies 72 are uniformly shaded or colored to indicate the same sign or phase of the wave function in the region of the upper streamer, and all of the lobe bodies 72a are also uniform but of a different color or shade to indicate a common sign or phase of the Wave function in the region of the lower streamer, which is the opposite of the sign of that of the upper streamer. This uniformity of wave function sign in the two streamers is characteristic of a ground state in the molecule of benzene.

FIG. 16 shows a model in which the same parts are rearranged to depict a benzene ring with an excited state molecular orbital. In this view, the upper orbital lobes are represented by alternating bodies 72 and 72a while the lower lobe bodies 72 and 72a alternate with the upper bodies. This alternate lobe shading indicates reverse phases of atomic orbital wave functions above and below each atom, which demonstrates the inability of the atomic orbitals to form uniform annular streamers as were present in the ground state. This is characteristic of an electronically excited state in the molecule.

For the representation of the lobe of an anti-bonding orbital, the lobe body 80, shown in FIG. 17 is provided. This lobe body 80 is of the bulbous, eccentric teardrop shape shown, and terminates in a tubular neck 82 having a bore 84 for receiving a coupling pin. The lobe bodies 80 can thus be mounted on the atom core bodies in the same manner as the lobe bodies 72, previously described.

The anti-bonding orbital lobe bodies 80 are used, for example, in the manner shown in FIG. 18, wherein a model of an ethylene molecule is shown. The model comprises two core bodies 22, connected by a coupling rod 42 and representing two carbon atoms in the sp. hybridized form. A lobe body is connected by a coupling pin 70 to the upper and lower corner of each of the core bodies 22 as shown in FIG. 8. A model of this type has significant predictive value in indicating for instance, what will occur in the molecule when the latter is exposed to ultra-violet light, or the shape which the molecule will assume when electronically excited.

The mode elements described above have additional practical predictive values in their ability to correlate the physical and chemical properties of materials with the geometries of not only ground states of molecules, but excited states as well, a :property not found in existing molecular models or assemblies.

While preferred embodiments of the invention have been shown and describe-d herein, it is obvious that numerous omissions, changes and additions may be made in such embodiments without departing from the spirit and scope of the invention.

What is claimed is:

1. A model assembly for representing the atomic and molecular orbital structure of atoms in a molecule, said assembly comprising a plurality of units representing atom cores, each of said units comprising a solid body having the form of a polyhedron with triangular planar faces and with a bore at each corner thereof arranged in accordance with the symmetry axes of valence orbitals and bond angles of the atom to be depicted by said unit, the bodies of said plurality of atom core units being of three types respectively defining a tetrahedron, a trigonal bypyramid and an octahedron depicting the forms of the hybridization states of a single atom, a plurality of units representing atomic orbital lobes and each comprising a hollow body of substantially ellipsoid shape having a terminal bore, and coupling means in the form of elongated members having end portions sized for frictional mounting within the bores of said atom core units and orbital lobe units for interconnecting selected atom core units and for connecting selected orbital lobe units to said atom core units to form semi-skeletal models of selected molecules including scale representations of bond angles, bond distances, atomic orbitals and internuclear distances, with the molecules shown in ground states and excited states.

2. A model assembly according to claim 1 in which said atom core bodies are made of elastomeric material and said coupling means includes a plurality of coupling rods for interconnecting said atom core units, said coupling rods each having a central shank of polygonal cross-section and terminal cylindrical end portions sized to fit frictionally within the corner bores of said atom core units, the central shanks of said coupling rods being respectively sized to represent to scale the bond distances of single bonds, double bonds and triple bonds.

3. A model assembly according to claim 1 in which said coupling means includes a plurality of elongated members having flexible central body portions capable of bending in the assembled model to depict a dynamic molecular condition.

4. A model assembly according to claim 1 in which said coupling means includes a plurality of pins sized for insertion within the corner bores of said atom core units, and an elongated tubular member of bendable plastic material sized to frictionally receive one of said pins in each end thereof.

5. A model assembly according to claim 1 in which the body of each of said atom core units is formed with a pin projecting from each corner thereof along an axis extending through the center of the polyhedron core unit body, and in which said coupling means includes an elongated flexible tube of sufiicient internal diameter to be frictionally mounted on said pins.

6. A model assembly according to claim 1 which also includes a plurality of hollow spherical bodies sized to represent terminal atoms, each of said bodies having a neck portion containing a bore sized to frictionally receive one of said elongated coupling members, whereby said spherical body may be connected to one of the corner bores of an atom core unit.

'7. A model assembly according to claim 1 in which said orbital lobe units are differently shaded to represent opposite polarities to depict in the assembled models ground state and excited state orbitals.

8. A model assembly according to claim 1 in which said plurality of orbital lobe units include units of bulbous, eccentric ellipsoid shape, to represent lobes of antibonding orbitals.

References Cited UNITED STATES PATENTS 8 3/1932 Dodge 35-18 2/ 1944 Brenneman 4626 X 12/1959 Parker 46 26 X 1/ 1960 Subluskey 3518 8/1967 Brumlik 35-18 FOREIGN PATENTS 10/1966 Germany.

US. Cl. X.R.

Images