The invention provides a method for the formation of small-size metal oxide particles, comprising the steps of a) preparing a starting aqueous solution comprising at least one of metallic ions and complexes thereof, at a concentration of at least 0.1 % w/w of the metal component; b) maintaining the solution at a temperature lower than 50° C. for a retention time in which hydrolysis takes place, the extent of the hydrolysis being sufficient to produce O.1 mmol protons per mmol of metal present in solution, wherein the time does not exceed 14 days, to form a system containing a retained solution; and c) adjusting the conditions in the system by at least one of the steps of: i) heating the retained solution to elevate the temperature thereof by at least 1° C.; ii) changing the pH of the retained solution by at least 0.1 units; and iii) diluting the retained solution by at least 20% whereby there are formed particles, wherein the majority of the particles formed are between about 2 nm and about 500 nm in size.
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