This work deals with the abundance, mode of occurrence, and origin of fluorine in Lopingian coals from the Lalang Coal Mine, Guangxi, southern China. The Lalang coal has a semi-anthracite rank and is characterized by superhigh-organic-sulfur (SHOS) content (4.46-11.34%). Fluorine concentration was determined by pyrohydrolysis plus a fluorine ion-selective electrode. Fluorine presents a significantly-enriched content in the Lalang coal, up to 2096 mu g/g in an individual coal bench. Fluorine is positively correlated with B in the coals present in this study; however, it does not show relevance with the metamorphism degrees of SHOS coals. The highly-elevated F in the Lalang coals occurs primarily in illite, fluorite, fluorapatite, and to a lesser extent, organic matter. The enrichment and occurrences of fluorine in coal are attributed to input from the sediment-source Yunkai Upland region, hydrothermal solutions originated from volcanic activities, marine invasions, original coal-forming flora and fauna, underground water circulating within the deep crust, and meteoric water. (C) 2017 Elsevier Ltd. All rights reserved.