Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 215-687-4 | CAS number: 1344-09-8
Categories
- Category name:
- Soluble silicates
Justifications and discussions
- Category rationale:
- The soluble silicates are structurally very similar. Silicon-oxide tetrahedra as the basic structural units are linked with each other via Si-O-Si bonds resulting in an infinite three-dimensional network. The negative charge of unshared oxygen atoms is balanced by the presence of sodium or potassium cations which are randomly spaced in the interstices. The extent to which balancing alkali ions are present in a given silicate is defined by the molar ratio SiO2/M2O (M = Na or K). The higher the molar ratio, the less sodium or potassium ions are present in the silica network and consequently the less alkaline the silicates are. Whereas the sodium and potassium salts have an amorphous threedimensional structure, the disodium salts (= metasilicates) are crystalline with penta- and nonahydrate differing from the anhydrous form only by their water of crystallisation. Once in aqueous solution, ll soluble silicates are subject to the same molecular speciation resulting in a mixture of monomeric tetrahedral ions, oligomeric linear or cyclic silicate ions and polysilicate ions. At environmental pH values the soluble silicates are present as poorly soluble amorphous silica and monomeric silicic acid. The biological properties of soluble silicates are mainly governed by their intrinsic alkalinity. Based on the available data the members of the soluble silicates category exhibit a similar toxicological profile (OECD SIDS, 2004).
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
