Quick lookup information:
Chemical Information for Chemists: A Primer - Stacks QD8.5.C44 2014
McGraw-Hill Encyclopedia of Science & Technology - Reference Q121.M3 2002
Good for the non-scientist
CRC Handbook of Chemistry & Physics (online - also print edition in Reference QD65.H3)
Tables of physical and chemical formulae, properties of substances, etc.
Hutchinson Dictionary of Scientific Biography (online via ebrary) - 2005
Entries range from a few paragraphs to several pages for very famous scientists
Dictionary of Scientific Biography - Reference Q141.D5 (1971)
Only useful for pre-1971 scientists, but much longer entries than the Hutchinson - this is a 15 volume set
Not specified