Chemically, metalloids are characterised-to varying degrees-by covalent bonding tendencies, acid-base amphoterism and the formation, in solution, of oxyanions. "They are distinguished from typical nonmetals by always giving compounds less acidic in character than the corresponding compounds of the nonmetals" ). The oxides are polymeric, glass formers, and amphoteric. 10 The chlorides are covalent and volatile; usually dissolve in organic solvents; and are partly or completely hydrolysed in water, some reversibly so.