ISE in which the membrane is a crystalline material prepared from either a single compound or a homogeneous mixture of compounds.
Examples: \(\ce{Ag2S}\), \(\ce{AgI}\)/\(\ce{Ag2S}\)
Source:
PAC, 2020, 92, 641. 'Terminology of Electrochemical Methods of Analysis (IUPAC Recommendations 2019)' on page 664 (https://doi.org/10.1515/pac-2018-0109)