TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The siloxane phosphonic acid group contains silsesquisiloxane. The phosphonic acid group containing silsesquisiloxane exhibits a completely or partially closed cage-like polyhedral silsesquisiloxane (when k is 6, 8, 10 or 12). The phosphonic acid group containing silsesquisiloxane exhibits a ladder-like or untextured silsesquisiloxane (when x is 1, y is 0 and R1 is phenylene). The phosphoric acid silylester exhibits phosphoric acid of formula (P(OSiR3R4R5)(OSiR6R7R8)(OSiR9R10R11)) (III) or (P(OSiR3R4R5)(OSiR6R7R8)(OH)) (IV) or mixture of O-silylated phosphoric acid ester are obtained through silylating phosphoric acid with one or more amino-, halo and/or alkoxysilane. The phosphoric acid alkyl ester is phosphoric acid of formula (P(OR12)(OR13)(OR14)) (IV) or (P(OR12)(OR13)(OH)) (VI). The catalyst is a metal such as nickel, palladium (both preferred), platinum, rhodium, ruthenium, osmium or iridium. The amount of catalyst is 0.01-1 molar equivalent. The nitrogen free solvent is diphenylether, benzophenone, diphenylsulfone, sulfolane, alkyl- or alkoxy substituted derivative of their compounds; aliphatic, (partially)aromatic oligo- and polyether; aliphatic, (partially)aromatic beta-diketone; alkyl-, aryl-, alkoxy- or aryloxy-substituted derivative of their compounds; aliphatic, (partially)aromatic ketoether; aliphatic, (partially)aromatic carboxylic acid; or aliphatic, (partially)aromatic carbonate and mixture of attached compound, preferably benzophenone, diphenylether (preferred) or diphenylsulfone.R3-R14 = alkenyl, (cyclo)alkyl, aralkyl or aryl (optionally replaced by heteroatoms).    TECHNOLOGY FOCUS - POLYMERS - Preparation (Claimed): Preparation of oligo- or polymer siloxane containing phosphonic acid comprising phosphonylating the halogenated oligo- or polymer siloxane containing one or more unit (II) of formula ((Si(A1a)xa(B1a)ya(Y3))ka-(Si(A1)x(B1)y(Y4)-(O)(4-(x+y)/2))k) with phosphoric acid silyl- and/or alkylester in presence of a catalyst, where the phosphonylating is carried out in an nitrogen free solvent at greater than or equal to150degreesC.Y3, Y4 = -((Si(A2a)xb(B2a)yb)kb) or ((Si(A3a)x(B3a)y-(O)(4-(x+y)/2))kc);A1, A1a-A3a = -R1-(X)n-; andB1, B1a-B3a = -R2-(Xa)m.Preferred Process: The process further comprises releasing the phosphoric acid group by alcoholysis of the silylester or ester splitting/-pyrolysis/thermolysis of the alkylester by increasing the temperature or by acidolysis with concentrated acid. EXAMPLE - Polyhedral phenyl-unit (20 g) and 1,1,2,2-tetrachloroethane (TCE) (40 ml) was dissolved in three-neck piston (250 ml) with magnetic stirrer. The mixture was heated at 110degreesC and elementary bromine (37.14 g) dissolved in TCE (40 ml) was added to the mixture and stirred for 15 minutes. The reaction mixture was cooled to room temperature and acetone (250 ml) was added. The obtained residue was washed thrice in ultrasound bath for 15 minutes with cyclohexane (100 ml) and tetrahydrofuran (100 ml). Then the mixture was filtered, dried and washed with cyclohexane (100 ml). The obtained product was dried at 120degreesC under vacuum in room temperature to obtain a brominated-polyhedral precursor compound (A). (A) (5 g) with aqueous-free nickel(II) chloride (623.1 g) was dissolved in three-neck piston (50 ml) with stirrer. The mixture was reacted at 190degreesC. Diphenyl ether (5 ml) under N-counter current was processed for 30 minutes. Triethylphosphite (4.99 g) was dropped through funnel into the mixture under stirring for 30 minutes. A color band of dark red was observed after 15 seconds of processes. After 3 minutes of strong swelling, discoloration was observed and processed for 8 hours at 180degreesC. Tetrahydrofuran was added to the mixture and stirred at 80degreesC. After tetrahydrofuran was evaporated, perhydrol (30%) was added. The solid component, which was free of cyclohexane was isolated and dried to obtain phosphonic acid polyhedral octaphenylsilsesquisiloxane (pho-phT8-1) (5.4 g).