Isomorphism and mixed crystals in 2-R-naphthalenes: evidence of structural subfamilies and prediction of metastable forms

• Published in: Journal of applied crystallography Vol. 32; no. 3; pp. 481 - 488
• Main Authors: Haget, Y., Chanh, N. B., Meresse, A., Bonpunt, L., Michaud, F., Negrier, P., Cuevas-Diarte, M. A., Oonk, H. A. J.
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01.06.1999; Blackwell
• Subjects: Aliphatic, non-condensed and condensed benzenic, and alicyclic compounds; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Organic compounds; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Phase diagrams; Metastable phases; Hydrocarbons; Binary systems; XRD; Experimental study; Condensed benzenic compound; Naphthalene derivatives; Bicyclic compound; Isomorphism; Phenols; Chemical composition; Fluorine Organic compounds; Organic compounds; Crystal structure
• ISSN: 1600-5767; 0021-8898; 1600-5767
• DOI: 10.1107/S0021889899002423

Solid–liquid binary phase diagrams and isothermal unit‐cell parameters as a function of composition are given for the high‐temperature form (P21/a, Z = 2) mixed crystals generated by 2‐fluoronaphthalene, naphthalene and 2‐naphthol with four other β derivatives of naphthalene. The study leads to the distinction between two high‐temperature forms (or types of packing). The first one (type 1) is taken by five 2‐R‐naphthalenes (R = F, Cl, Br, SH, CH3; the first subfamily), the second one (type 2) by naphthalene itself and 2‐naphthol (R = H, OH; the second subfamily). The crystallographic data also allow an estimation of unit‐cell parameters for the metastable forms of naphthalene (type 1, a = 8.0, b = 5.95, c = 8.6 Å, β = 116°) and 2‐fluoronaphthalene (type 2, a = 8.336, b = 5.915, c = 9.000 Å, β = 122.23°), supporting an interpretation, in terms of crossed isodimorphism, of the observed two‐phase regions in systems in which the components do not belong to the same subfamily.