Molecular solids are poor electrical conductors,[4][5] although some, such as TTF-TCNQ are semiconductors (ρ = 5 x 102 Ω−1 cm−1).[5] They are still substantially less than the conductivity of copper (ρ = 6 x 105 Ω−1 cm−1).[8] Molecular solids tend to have lower fracture toughness (sucrose, KIc = 0.08 MPam1/2)[11] than metal (iron, KIc = 50 MPa m1/2),[11] ionic (sodium chloride, KIc = 0.5 MPa m1/2),[11] and covalent solids (diamond, KIc = 5 MPa m1/2).[12] Molecular solids have low melting (Tm) and boiling (Tb) points compared to metal (iron), ionic (sodium chloride), and covalent solids (diamond).[4][5][8][13] Examples of molecular solids with low melting and boiling temperatures include argon, water, naphthalene, nicotine, and caffeine (see table below).[13][14] The constituents of molecular solids range in size from condensed monatomic gases[15] to small molecules (i.e. naphthalene and water)[16][17] to large molecules with tens of atoms (i.e. fullerene with 60 carbon atoms).[18]
Melting and boiling points of metallic, ionic, covalent, and molecular solids
^Simon, A.; Peters, K. (1980). "Single-Crystal Refinement of the Structure of Carbon Dioxide". Acta Crystallogr. B. 36 (11): 2750–2751. doi:10.1107/s0567740880009879.
^Lehmann, C. W.; Stowasser, Frank (2007). "The Crystal Structure of Anhydrous Beta-Caffeine as Determined from X-ray Powder-Diffraction Data". Chemistry: A European Journal. 13 (10): 2908–2911. doi:10.1002/chem.200600973. PMID17200930.
^ abHall, George (1965). Molecular Solid State Physics. Berlin, Germany: Springer-Verlag.
^ abcdefgFahlman, B. D. (2011). Materials Chemistry. Berlin, Germany: Springer.
^ abcdefSchwoerer, M.; Wolf, H. C. (2007). Organic Molecular Solids. Weinheim, Germany: Wiley-VCH.
^Omar, M. A. (2002). Elementary Solid State Physics. London, England: Pearson.
^Patterson, J.; Bailey, B. (2010). Solid-State Physics. Berlin, Germany: Springer.
^ abcdTurton, R. (2010). The Physics of Solids. New York, New York: Oxford University Press Inc.
^Keer, H. V. (1993). Principles of Solid State. Hoboken, New Jersey: Wiley Eastern Limited.
^ abcIsraelachvili, J. N. (2011). Intermolecular and Surface Forces. Cambridge, Massachusetts: Academic Press.
^ abcVarughese, S.; Kiran, M. S. R. N.; Ramamurty, U.; Desiraju, G. R. (2013). "Nanoindentation in Crystal Engineering: Quantifying Mechanical Properties of Molecular Crystals". Angewandte Chemie International Edition. 52 (10): 2701–2712. doi:10.1002/anie.201205002. PMID23315913.
^Field, J. E., ed. (1979). The Properties of Diamonds. New York, New York: Academic Press.
^ abcdefghijklmnopHaynes, W. M.; Lise, D. R.; Bruno, T. J., eds. (2016). CRC Handbook of Chemistry and Physics. Boca Raton, Florida: CRC Press.
^ abO'Neil, M. J., ed. (2013). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, United Kingdom: Royal Society of Chemistry.
^Barret, C. S.; Meyer, L. (1965). Daunt, J. G. (ed.). Low Temperature Physics: The Crystal Structures of Argon and Its Alloys. New York, New York: Springer.
^Eisenberg, D.; Kauzmann, W. (2005). The Structures and Properties of Water. Oxford, UK: Oxford University Press.
^Harvey, G. R. (1991). Polycyclic Aromatic Hydrocarbons: Chemistry and Carcinogenicity. Cambridge, UK: Cambridge University Press.
^Jones, W., ed. (1997). Organic Molecular Solids: Properties and Applications. Boca Raton: CRC Press.