# Cyano Silica Gel > modified silica gel used in chromatography **Wikidata**: [Q115221589](https://www.wikidata.org/wiki/Q115221589) **Source**: https://4ort.xyz/entity/cyano-silica-gel ## Summary Cyano Silica Gel is a chemical substance and modified form of silica gel utilized primarily as a stationary phase in chromatography. As a specialized column-packing material, it is derived from synthetic amorphous silicon dioxide and is engineered to separate complex chemical mixtures. It belongs to a class of functionalized gels—alongside C18 and Amino variants—tailored for specific analytical selectivity. ## Key Facts * **Definition:** A modified silica gel used in chromatography, classified as a chemical substance. * **Parent Material:** Derived from silica gel, a granular, vitreous, porous form of synthetic amorphous silicon dioxide (SiO₂). * **Primary Function:** Serves as a column-packing material and stationary phase in chromatography. * **Classification:** Subclass of `column packing material`, `silica gel`, and `absorbent`. * **Related Variants:** Part of a group of modified silica gels that includes C18, C8, Amino, and Phenyl silica gels. * **Base Material Density:** The underlying silica gel has a density of 2.20 g · cm⁻³ (at 20 °C). * **Thermal Properties:** The base silica gel matrix has a melting point of 3 110 °F and a boiling point of 4 046 °F. * **Chemical Stability:** The parent material, synthetic amorphous silica, is chemically inert and possesses a vapor pressure of 0 mm Hg. * **Safety Limits:** The base silica material is subject to NIOSH exposure limits: a Time‑Weighted Average (TWA) of 6 mg · m⁻³ and an Immediately Dangerous to Life or Health (IDLH) limit of 3 000 mg · m⁻³. * **Identifiers (Parent Class):** Associated with CAS Registry Numbers 68855‑54‑9 (silica gel) and 112926‑00‑8 (silicon dioxide). ## FAQs ### What is Cyano Silica Gel used for? Cyano Silica Gel is used as a stationary phase in high-performance liquid chromatography (HPLC). It facilitates the precise separation of complex mixtures by acting as a selective absorbent in the column-packing process. ### How does Cyano Silica Gel relate to standard silica gel? Cyano Silica Gel is a modified subclass of silica gel. While standard silica gel is often used as a desiccant, Cyano Silica Gel is chemically functionalized to tailor its selectivity for specific analytical separation tasks in chromatography. ### What are the hazards associated with the silica gel base? While the material is chemically inert, exposure to fine particles of the underlying silica gel poses inhalation hazards. Occupational safety guidelines regulate exposure with a specific Time‑Weighted Average limit of 6 mg · m⁻³. ### Can the properties of the base silica gel change? The base structure consists of a cross-linked network of Si–O bonds. While it can be regenerated through heated drying to restore adsorption capacity, its fundamental physical properties—such as its high melting point (3,110°F) and non-volatility—remain constant. ## Why It Matters Cyano Silica Gel matters because it enables the high-precision analysis required in modern analytical chemistry. By modifying the surface of standard silica gel, this material allows scientists to tailor the "selectivity" of the chromatography process, making it possible to isolate and identify specific components within complex chemical mixtures that unmodified silica cannot distinguish. It represents a critical evolution of the desiccant material into a high-value scientific tool, bridging the gap between simple moisture absorption and complex molecular separation. Furthermore, it retains the beneficial properties of its parent material—such as high thermal stability and a robust, porous structure—ensuring reliability under the high-pressure conditions of liquid chromatography. ## Notable For * **Chromatographic Selectivity:** Distinguished from standard desiccant silica by its specific modification for separating chemical compounds. * **High Thermal Stability:** Inherits the parent material's ability to withstand extreme temperatures (melting point > 3,000°F). * **Non-Volatility:** Exhibits practically zero vapor pressure (0 mm Hg), ensuring it does not evaporate during use. * **Structural Versatility:** Utilizes the high surface area of the synthetic amorphous silica matrix to facilitate surface modifications. * **Regulated Safety:** Subject to strict NIOSH exposure limits due to the potential hazards of fine silica particles. ## Body ### Composition and Structure Cyano Silica Gel is a chemical substance defined by its modification of the silica gel matrix. The foundation of this material is synthetic amorphous silicon dioxide (SiO₂), which forms a granular, vitreous, and highly porous network. This structure consists of a cross-linked network of Si–O bonds, providing a high surface area essential for its function. The "Cyano" designation refers to the specific chemical functionalization applied to this base matrix. This modification places it within a specialized category of chromatography media, distinct from other variants such as C18, C8, Amino, and Phenyl silica gels. ### Physical and Chemical Properties The physical characteristics of Cyano Silica Gel are largely determined by its parent material, silica gel. * **Density:** The material has a density of 2.20 g · cm⁻³ when measured at 20 °C. * **Thermal Stability:** It possesses extreme thermal resistance, with a melting point of 3 110 °F and a boiling point of 4 046 °F at 760 mm Hg. * **Volatility:** It is practically non-volatile, maintaining a vapor pressure of 0 mm Hg under normal conditions. * **Molecular Mass:** The underlying silicon dioxide has a reported molecular mass of 60.1 Da. ### Applications in Chromatography Cyano Silica Gel is primarily utilized as a column-packing material. In this role, it functions as the stationary phase in chromatography. Unlike unmodified silica gel, which is widely used as a hygroscopic desiccant to protect moisture-sensitive goods like pharmaceuticals and electronics, the Cyano variant is engineered for analytical chemistry. It allows for the precise separation of mixtures, leveraging its modified surface to interact differentially with various chemical components as they pass through a column. ### Safety and Exposure While the chemical substance is generally inert, the handling of silica-based materials requires adherence to safety regulations. * **Occupational Exposure:** The National Institute for Occupational Safety and Health (NIOSH) has established a Time‑Weighted Average (TWA) exposure limit of 6 mg · m⁻³. * **Immediate Danger:** The Immediately Dangerous to Life or Health (IDLH) concentration is set at 3 000 mg · m⁻³. These limits address the risks associated with inhaling fine silica particles, which can pose health hazards despite the material's chemical stability. ### Identifiers and Classifications Cyano Silica Gel is classified as a subclass of `gel`, `column-packing material`, and `absorbent`. It falls under the broader class of `synthetic amorphous silica`. Key identifiers associated with the base silica gel substance include: * **CAS Registry Numbers:** 68855‑54‑9 (silica gel) and 112926‑00‑8 (silicon dioxide). * **KEGG ID:** D06521. * **EC Number:** 272‑489‑0. * **NIOSH Pocket Guide ID:** 0552. * **UMLS CUI:** C0074530.