Crystal data for the dihydrate and anhydrate of 11-aminoundecanoic acid

X-ray and electron diffraction studies were made on the two phases of 11-aminoundecanoic acid, C₁₁H₂₁NO₂. Phase I: dihydrate, monoclinic, C2/c, z = 8, a = 15.96±0.03, b = 4.71±0.01, c = 35.48±0.08 Å, β = 82.1±0.3°. Phase II: anhydrate, orthorhombic, P2₁2₁2₁, z = 4, a = 7.526±0.003, b = 4.623±0.003, c = 32.42±0.01 Å.