Overview

Tin(II) iodide, commonly called stannous iodide, is a binary inorganic compound with the formula SnI2. It contains tin in the +2 oxidation state combined with iodide anions. The compound is a dense, often red-to-brown crystalline solid that is used mainly as a chemical reagent and precursor in research. For basic database listings see chemical databases.

Composition and structure

SnI2 consists of Sn2+ and I− ions. The tin(II) center typically exhibits an asymmetric coordination environment because of the stereochemically active lone pair on Sn(II), a common feature of many divalent post‑transition metal cations. X‑ray studies have shown distorted coordination by iodide ligands rather than an ideal symmetric geometry. For structural details consult specialized crystallography sources at structural references.

Preparation and chemical behavior

Common laboratory preparations include direct combination of elemental tin and iodine under controlled heating, or reduction of tin(IV) iodide. SnI2 is moderately reactive: it can be hydrolyzed by water and is sensitive to strong oxidants that convert tin(II) to tin(IV). It also acts as a mild Lewis acid and a reducing agent in some organic and inorganic transformations. Practical synthesis routes and reaction examples are discussed in synthetic method collections such as synthetic protocols.

Physical properties and uses

Typical physical properties include relatively low volatility and crystalline habit; its calculated molar mass is about 372.5 g·mol−1. Tin(II) iodide finds use as a reagent in laboratory chemistry, a precursor to other tin compounds, and in materials research where tin halides serve as building blocks for low‑dimensional or halide‑based materials. Applications and material studies are reviewed in specialist texts and articles available via technical literature.

Safety and handling

SnI2 should be handled with care: it can be an irritant and, like many soluble iodide-containing compounds, may pose toxicity risks if ingested or inhaled. It should be stored dry, away from oxidizing agents, and handled in a well‑ventilated area or inert atmosphere for sensitive preparations. For safety data and regulatory guidance consult standard safety sources at safety references.

  • Key points: formula SnI2, tin in +2 oxidation state, crystalline solid, used as reagent/precursor.
  • Distinctive feature: stereochemically active lone pair on Sn(II) influences its coordination and reactivity.