A method of forming a powder and/or discrete gel particles of a compound selected from the group of a metallic oxide, a metalloid oxide, a mixed oxide, an organometallic oxide, an organometalloid oxide, an organomixed oxide resin, and/or an organic resin from one or more respective organometallic precursor(s), organometalloid precursor(s) and/or organic precursors and mixtures thereof, comprising the steps of passing a gas into a means for forming excited and/or unstable gas species (1a), typically an atmospheric plasma generating means; treating said gas such that upon leaving said means the gas comprises excited and/or unstable gas species which are substantially free of electrical charges at a temperature of between 10° C. and 500° C. A gaseous and/or liquid precursor is then introduced (50a,50b) into said excited and unstable gas species in a downstream region external (20) to the means for forming excited and/or unstable gas. The interaction between the precursor and the excited and unstable gas species results in the formation of a powder and/or discrete gelled particles which are subsequently collected. The particles prepared by the method may be subsequently functionalised.