Gemstone-like compound

Diamondoid materials encompass all materials that

• do not diffuse at room temperature
• are stiff enough to keep their shape under thermal movement
• have dense three dimensional networks of covalent bonds - (short bond loops => no polymeres)
• (not necessarily but desirable) do not react or dissolve in water

list of potential structural compounds

If one looks at the most common / most accessible elements and their simplest compounds one finds a list of potential structural building materials:

Compounds that do not react or dissolve in water:

• carbon in diamond lonsdaleite or intermediate forms
• silicon carbide (also cubic or hexagonal)
• silicon (also cubic or hexagonal)
• B4C boron carbide
• SiB4; SiB6 ?
• four allotropes of elementar boron
• AlB12
• beta-C3N4 beta carbon nitride
• N4Si3 silicon nitride
• cubic BN cubic boron nitride
• BP boron phosphide
• SiO2 quartz (& allotropes)
• Al2O3 aluminum oxide - aka sapphire
• Fe3C iron carbide aka cementite
• iron silicides & iron borides ? - unknown properties
• FeS2 FeS iron sulfides - pyrite marcasite ...
• Fe2O3 Fe3O4 hämatite magnetite
• Cu3P CuS (copper is rare)

Surisingly titanium forms chemically rather stable compounds with many nonmetals.

• TiC titanium carbide
• TiSi2 ?(unknown properties)
• TiB2 titanium diboride
• TiN titanium nitride
• TiP Titanium Phoshide (too metallic?)
• TiS titanium sulphide
• TiO2 Ti2O3 titanium oxides

materials which very slowly dissolve in water but are thought to be rather nontoxic

• Al4C3
• AlN (oxidizes on air)
• the three natural allotropes of elementar phosphorus
• S2N2 S4N4 (SN)x - diamondoid?
• allotropes of elementar sulfur

simplest most water stable compounds of abundant alkaline eart metals

• MgB2 magnesium diboride (high temperature superconductor)
• MgO magnesium oxide aka magnesia
• CaB2 calcium diboride
• CaS calcium sulfite

most water stable solid fluorides

• TiF3 titanium fluoride
• MgF2 magnesium fluoride aka sellaide
• CaF2 calcium fluoride aka fluorite

dangerous materials to stay away from

• solid nitrogen (except you want to make highly potent explosives)
• AlP extremely toxic
• Al2S3 highly toxic
• sulphur phosphorus compounds - highly toxic
• Fe3P
• BF3 BCl3 PCl3