A lot vs. Alot: 9 Grammatical Pitfalls
any of a group of naturally occurring compounds of arsenic, oxygen, and various metals, most of which are rare, having crystallized under very restricted conditions. At the mineralogically famous Langban iron and manganese mines in central Sweden, more than 50 species of arsenate minerals have been described, many peculiar to the locality. Such compounds occur in open cavities and resulted from the reaction of arsenic acid (H3AsO4) upon pyrochroite [manganese hydroxide; Mn(OH)2] at moderate to low temperature. Arsenates at other localities are often oxidation products of arsenide ores and are deposited at low temperatures in late-stage veins and open cavities.