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 occurrence of two different zinc chlorohydroxosulfates in various kinds of atmospheres. One of the compounds, NaZn4Cl(OH)6SO4.6H2O, is abundant in marine environments. The crystal structure has been determined in the space group P3BAR. The unit cell is hexagonal with a = 8.3691 angstrom and c = 13.047 angstrom. The other compound, with the approximate composition 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 literature, whereas the latter is not reported earlier.