Method for producing a SiO 2 xerogel with pores ranging from 1000 nm to 50 nm, a density less than 400 kg/m 3, characterised in that the SiO 2 xerogel is produced by way of a sol-gel process from a silicon compound, in particular sodium silicate, silicas such as pyrogenic silicas, precipitated silicas, layered silicates, alkoxysilanes, modified alkoxysilanes, in particular Si 4, where R = organic residue, here preferably tetraethoxysilane TEOS, Si(OEt) 4 and a. without solvent exchange b. by means of subcritical drying c. with the aid of organic monomers which are monomers for epoxides, and which are soluble or dispersible in polar protic solvents, preferably mixtures of water and an alcohol, here preferably ethanol, and an organically modified alkoxysilane having the general formula R n Si(OR') 4-n, where n = 0-3; R, R' = organic residues, which are added to the starting solution, the sol phase or after commencement of gelification, such that the organic component content by weight of the silicate component is 20% at most, in particular 15% at most, preferably however 8% at most d. and which after the drying at 1 bar is subjected to a pyrolysis, which is carried out in excess of 300°C in an oxygenated atmosphere, and subsequently to an oxidative heat treatment in excess of 300°C, wherein the method comprises the following steps: carrying out the sol-gel process, wherein during the gelification an SiO 2 network is formed together with the organic particles, wherein during the gelification the organic particles are formed from the organic monomers, and are linked to the SiO 2 network covalently, and carrying out the drying, the pyrolysis and the oxidative heat treatment, wherein these cause the organic particles to be removed as far as possible from the gel structure, so that imperfections arise in the SiO 2 network, wherein the carbon residue which has been formed is present in a quantity of less than 10% in the resulting SiO 2 xerogel. a. without solvent exchange b. by means of subcritical drying c. with the aid of organic monomers which are monomers for epoxides, and which are soluble or dispersible in polar protic solvents, preferably mixtures of water and an alcohol, here preferably ethanol, and an organically modified alkoxysilane having the general formula R n Si(OR') 4-n, where n = 0-3; R, R' = organic residues, which are added to the starting solution, the sol phase or after commencement of gelification, such that the organic component content by weight of the silicate component is 20% at most, in particular 15% at most, preferably however 8% at most d. and which after the drying at 1 bar is subjected to a pyrolysis, which is carried out in excess of 300°C in an oxygenated atmosphere, and subsequently to an oxidative heat treatment in excess of 300°C, carrying out the sol-gel process, wherein during the gelification an SiO 2 network is formed together with the organic particles, wherein during the gelification the organic particles are formed from the organic monomers, and are linked to the SiO 2 network covalently, and carrying out the drying, the pyrolysis and the oxidative heat treatment, wherein these cause the organic particles to be removed as far as possible from the gel structure, so that imperfections arise in the SiO 2 network, wherein the carbon residue which has been formed is present in a quantity of less than 10% in the resulting SiO 2 xerogel.