ZINC CHLOROHYDROXOSULFATES - NEWLY-DISCOVERED CORROSION PRODUCTS ON ZINC - STRUCTURE DETERMINATION OF NAZN4CL(OH)6SO4.6H2O AND X-RAY STUDY OF ZN4CL2(OH)4SO4.5H2O

Recent phase identification of corrosion products on a large number of field- and laboratory-exposed zinc specimens shows the frequent occur rence of two different zinc chlorohydroxosulfates in various kinds of atmospheres. One of the compounds, NaZn4Cl(OH)6SO4.6H2O, is abundant i n marine environments. The crystal structure has been determined in th e space group P3BAR. The unit cell is hexagonal with a = 8.3691 angstr om and c = 13.047 angstrom. The other compound, with the approximate c omposition Zn4Cl2(OH)4SO4.5H2O, occurs in industrial, rural and urban atmospheres. The unit cell is monoclinic with a = 10.92 angstrom, b = 4.1365 angstrom, c = 7.1671 angstrom and beta = 102.621-degrees. A few observations of the former have previously been reported in the liter ature, whereas the latter is not reported earlier.