Triangulation number of the SARS CoV-19 virus
Coronaviruses, like many viruses with a lipid membrane, are pleomorphic. The individual particles don't have a consistent shape. Here is a cryo-electron micrograph of SARS-CoV-1:


It might not be obvious, but each particle seen here is unique, they are not different rotations of identical copies. Since there is no consistent symmetry, there can be no triangulation number.

The image is from the following reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1563832/