Osmium tetroxide (OsO4) is a compound of significant interest due to its unique chemical properties and critical applications, particularly in scientific research. Despite Osmium's general inertness, OsO4 stands out as a volatile and toxic substance, demanding meticulous handling protocols. This compound, with the chemical formula OsO4, plays a crucial role in various scientific disciplines, from organic synthesis to biological specimen preparation.

In the realm of organic synthesis, Osmium tetroxide is renowned for its ability to perform cis-dihydroxylation of alkenes, a process that adds two hydroxyl groups to a double bond in a stereospecific manner. This reaction is fundamental in creating vicinal diols, which are important intermediates in the synthesis of complex organic molecules. While OsO4 is expensive and toxic, its use can be made catalytic by employing reoxidants to regenerate the active Os(VIII) species, making its application more feasible and cost-effective. The Osmium tetroxide toxicity is a primary concern that necessitates strict laboratory safety measures.

Biologically, Osmium tetroxide is indispensable as a staining agent in electron microscopy. Its high electron density and ability to bind with lipids enhance the contrast of biological samples, allowing for detailed visualization of cellular structures like membranes. This staining property is also utilized in scanning electron microscopy as an alternative to metal coating. OsO4 serves to fix tissues, preserving their structure for microscopic examination. The handling of Osmium tetroxide solutions requires strict adherence to safety guidelines to prevent exposure, as it can cause irreversible damage to the eyes and respiratory tract.

The osmium chemical formula and its associated osmium CAS number are critical identifiers for this compound. Understanding the osmium properties, particularly the reactivity and volatility of OsO4, is paramount for researchers. Despite the challenges associated with its toxicity, Osmium tetroxide's utility in facilitating complex organic reactions and enabling high-resolution biological imaging underscores its importance in scientific advancement. For any laboratory working with Osmium tetroxide, consulting safety data sheets and following established protocols is non-negotiable.