Enormous variation in homogeneity and other anomalous features of room temperature superconductor samples: a Comment on Nature 615, 244 (2023)

The resistive transition width of a recently discovered room temperature near-ambient-pressure superconductor [1] changes by more than three orders of magnitude between different samples, with the transition temperature nearly unchanged. For the narrowest transitions, the transition width relative to $T_c$ is only $0.014\mathrm{\%}$. The voltage-current characteristics indicate vanishing critical current, and the normal state resistance is unusually small. These anomalous behaviors and other issues indicate that this system is not a superconductor. Implications for other hydrides are discussed.