Normal (n-) fatty acids (monobasic carbon acids) СnН2nО2 (or Сп–1Н2n+1СООН) are of high significance for vital functions of plants and animals. Probably n-fatty acids and n-alcohols being among the components of the ancient organic matter became the “raw staff” at forming petroleum hydrocarbons. A molecule of a n-fatty acid is an aliphatic chain terminated in methyl group CH3 and carboxyl group COOH. Hydrogen bonds between carboxyl groups of adjacent molecules determine the molecule packing in a crystal. These bonds join molecules into dimers terminated in methyl groups CH3 at both the sides. The dimers form layers with mutually parallel long axes. Methyl groups CH3 cause interaction between the layers.