Description General description (21) Black carbon atom parts: (9) trigonal, (12) tetrahedral (13) Red oxygen atom parts: (2) single hole, (11) two-hole angular (25) White hydrogen atom parts: (22) single hole, (3) two-hole linear (11) Blue nitrogen atom parts: (2) two-hole angular, (6) trigonal, (3) tetrahedral (1) Yellow two-hole angular sulfur atom part (1) Purple tetrahedral phosphorus atom part (40) Medium length grey links (10) Flexible long grey links Storage box Instructions Top quality Molymod molecular model sets are for use by students, teachers, and researchers. May be upgraded or customized with additional model parts, for more info, go to sigma-aldrich.com and enter Molymod in our search engine. Scale is 2.8 cm =100 pm (open style) and 1.45 cm = 100 pm (compact, semi-space-filling). Sets include standard color-coded plastic atom centers (with bond holes set at the appropriate angles), bonding links, and a plastic storage box. Set pictured is representative of the Student set. See our Selection Guide for detailed descriptions of set contents. Legal Information Molymod is a registered trademark of Spiring Enterprises Ltd.