Sodium cyanoborohydride, also known as sodium borohydride cyanide, is a white crystalline solid with the chemical formula NaBH3CN. It is a mild and selective reducing agent commonly used in organic synthesis for the reduction of various functional groups, such as aldehydes, ketones, imines, and alkyl halides. Sodium cyanoborohydride exhibits good stability in aqueous and alcoholic solutions and is relatively safe to handle compared to other reducing agents.