IRTF spectra for 17 asteroids from the C and X complexes: A discussion of continuum slopes and their relationships to C chondrites and phyllosilicates

► We use continuum slope between 1.8 and 2.5 μm against 1.0-1.75 μm to characterize asteroids. ► We suggest C complex asteroid surfaces are decomposed kaolinite or montmorillonite. ► We suggest X complex asteroids are decomposed montmorillonite or serpentine. ► We link various C chondrite meteorites to various asteroid classes. ► CI to Cgh, CV and CR to Xc, CK to Ch or Cgh, CI/CM to C, and CM to Xk.