Crystal Structure, Solid-State NMR Studies and Iglo Calculations of 1-Hydroxycyclohexanephosphonic Acid

X-ray diffraction of 1-hydroxycyclohexanephosphonic acid, C6H13O4P, gives the following crystal data: orthorhombic, P212121 (no. 19), a = 6.558(1), b = 7.644(2), c = 16.271(1) Å, V = 815.65 Å3, Z = 4, and Dx = 1.467 g/cm3. The molecular structure shows a chair conformation of the cyclohexane ring with the phosphonate group in equatorial position. The asymmetric unit consists of the formula unit. Solid-state 31P CP MAS NMR spectroscopy of different crystallization fractions of the title compound gives two sets of principal values of the nuclear magnetic shielding tensor caused by different modifications of the acid. According to IGLO caculations the most shielded component is almost along the P[dbnd]O bond. The results are compared with the principal values of some other C6 phosphonic acids.