Distribution of hydroxyl clouds in the Galaxy

Distribution of molecular clouds in the Galaxy is investigated on the base of survey of the galactic plane in hydroxyl lines at 1665 and 1667 MHz. The cloud distances are due to a relationship between hydroxyl absorption feature parameters and heliocentric distances. Radial distributions of the molecular clouds in four galactocentric quadrants have been obtained. Concentration of OH clouds into a molecular ring agrees with the radial distribution of CO and CH interstellar molecules in the Galaxy. It is shown that hydroxyl cloud complexes distribution can be represented by a two-armed spiral with pitch angles of 60.3 and 50.4