Silica polymorph and process for preparing same
US4073865A · kind A · utility
113Cited by
1References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1976 |
| Grant date | Feb 14, 1978 |
| Priority date | — |
| Expiry date | Sep 27, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S423/22
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Large crystals of a silica polymorph having a characteristic X-ray diffraction pattern, a specific gravity of 1.70 .+-. 0.05 g/cc. and a mean refractive index of 1.39 .+-. 0.01 after calcination in air at 600.degree. C., are prepared by a hydrothermal process in which fluoride anions are included in the reaction mixture. The crystals, which can be as large as 200 microns, exhibit a substantial absence of infrared adsorption in the hydroxyl-stretching region and also exhibit an exceptional degree of hydrophobicity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.