Simple Molecular Model

thingiverse

This is another molecular model. I decided to make my own model. I wanted one simple, easy to print, easy to connect, and customizable. I had this idea when I was teaching geometry in General Chemistry I and Instrumentation for the Teaching of Chemistry in 2019. The experience of the students touching a real molecule model is completely different from a virtual experience. The most import part in a model is the connector or atom. There is no need the shape of connectors be spheric. In my experience, it is more important the color instead of the shape. I designed them to be easy print. There are four connectors that you can represent the major molecules, geometries, hybridizations, for different purposes (molecules and crystals). I create them in the OpenSCAD. You can change the size of atoms, diameter of the holes, shape, etc. You can print as many as you want. You can paint the atoms or print them using filaments with different colors. I suggest you follow the standard color for atoms. https://en.wikipedia.org/wiki/CPK_coloring I found lollipop sticks made of PET (polyethylene terephthalate) in party supply stores to connect the atoms. I found two sizes. One has 280mm long, 4.3mm of outer diameter, and 0.5mm of thickness wall. The other one has 90mm long, 35mm of outer diameter, and 32mm of inner diameter. I chose the transparent tubes of 280mm long. You can use barbecue sticks too but it is not beautiful. To represent a nonbonding electron pair I usually leave connected a stick without an atoms at the end. I upload stl files of connectors with 4.3mm of holes. You need to check the outer diameter of your stick. I usually cut the stick in smaller length of 7.0mm or 3.5mm. To improve the fit the stick inside the hole you can use a pencil to increase a little bit the diameter at the end of the stick. For the Pi bonds I used rubber bands connecting sticks (orbitals). I don't want a real representation. I need a model. I am still thinking about the Pi bounds. But, rubber bands works and it is simple. I uploaded photos of D-glucose, benzene, ciclohexane (chair and boat conformation), methane (all in red), and ethanol. If you leave the stick not too short you can talk about the vibration of the structure. You can construct inorganic structures too like crystals.