The CRC Handbook of Chemistry and Physics is a one stop reference for chemistry. It is published by CRC Press which used to be the Chemical Rubber Company. An online edition also exists.
Among the useful information in the handbook is a section that lists many properties of almost all chemical compounds one is likely to encounter, as well as structural diagrams of organic compounds, a table of known isotopes for every element, and a wealth of other information related to chemistry and physics.
- 2003 edition: fptl.ru/biblioteka/spravo4niki/handbook-of-Chemistry-and-Physics.pdf
- 1920 (8th) edition: https://archive.org/details/HandbookOfChemistryAndPhysics8thEd.1920
- Online edition : http://www.hbcponline.com/