FuROY helped researchers uncover two additional crystal forms of ROY by acting as a molecular cousin in mixed-crystal seeding. The 2020 report put the count at ten forms, but that is a historical figure: a 2025 study reported the fourteenth known ROY polymorph, O22.
What ROY and its polymorph record mean
ROY is the common name for 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile. Its nickname reflects its red, orange and yellow crystal forms. A polymorph is a crystal structure of the same chemical compound that differs from another form’s structure; the chemical composition stays the same, while physical properties can differ. Lian Yu’s 2010 review used diamond and graphite as a familiar comparison for materials with the same composition but different structures and properties. Yu’s review
As an Amazon Associate I earn from qualifying purchases.
The number of recognized ROY forms depends on when they were counted and how completely they were characterized. In a 2025 primary study, the authors described O22 as the fourteenth known form, following thirteen previously identified forms. The 2025 study
Recommended Free Tools
How FuROY helped reveal two more ROY forms
In a report published on July 29, 2020, Chemistry World described a method that used FuROY, a close molecular mimic of ROY. The two compounds differ at one atom: FuROY has oxygen where ROY has sulfur. Researchers added a small mixed ROY–FuROY crystal to either a supercooled ROY droplet or a supercooled suspension in water. The mixed crystal acted as a seed, and the experiments yielded two additional ROY polymorphs. Chemistry World’s 2020 report
#1 Best Overall
- Heat & Create: Shape and mold our high-quality plastic pellets by heating them with hot water (>150F). Perfect for cosplayers and hobbyists seeking precision and versatility.
- Strong & Reusable: Our durable plastic pellets can be melted, molded, and reused multiple times. Build, reshape, and enhance your creations with ease. Ideal for long-lasting projects.
- Idea & Instruction Booklet Included: Unleash your creativity with our comprehensive 12-page color booklet. Discover exciting techniques and step-by-step instructions for stunning results.
- Make, Mend & Modify: Enhance your crafting, art, and repair projects with ease. Our moldable plastic is perfect for model making, prototyping, DIY repairs, and intricate modifications.
- Versatile & Durable Material: Craft with confidence using our top-grade moldable plastic pellets. Paint, drill, cut, or attach them seamlessly for exceptional craftsmanship and outstanding durability.
The report described a tally of ten forms at the time, then noted that another well-characterized form had brought the figure to eleven. Those are dated counts, not the current total; the later study’s count of fourteen includes O22. Chemistry World 2025 study
Why a polymorph can matter
Different crystal structures can produce different physical properties, which can matter in pharmaceutical and specialty-chemical manufacturing. For example, polymorphs can differ in melting behaviour and bioavailability. ROY is especially useful to researchers because many forms can be kinetically stable and crystallize from the same liquid under similar conditions. Yu’s 2010 review
Which form appears is not determined simply by which one nucleates first. As Yu explains, one form may nucleate slowly but become abundant because it grows quickly or nucleates on another form. ROY’s many observed forms reflect both thermodynamic stability and kinetic access to crystallization. This makes it a model for exploring how molecular conformation, crystal packing and crystallization conditions interact—not a shortcut to predicting the next compound with many forms. Yu wrote in 2010, “Despite many studies of ROY, it is still impossible to predict the next molecule that is equally or more polymorphic.” Yu’s review
Rank #2
- Let Imagination Take the Lead: Whether you are a professional artist or passionate about DIY crafts, the Formitcrafts melting plastic pellets are a must-have for turning your ideas into unique artworks!
ROY’s colours do not have one universal explanation
The colour differences are associated with structural differences, but the mechanism is not identical for every ROY form. In a 2021 study, Warren, McGowan, Renton, Morrison and Funnell measured orange-needle ROY crystals under high pressure. Between ambient pressure and 4.18 GPa, the crystals changed reversibly from pale orange toward dark red, while the molecule itself deformed only minimally. The authors attributed this behaviour to pressure-sensitive intermolecular π-stacking interactions. The 2021 study in Chemical Science
What scientists compare across ROY forms
To understand why a particular form appears and how it differs, researchers can compare its crystal structure and molecular conformation, colour and crystal shape, stability and kinetic accessibility, and the degree to which its structure has been characterized. The changing count is a reminder that identifying and confirming polymorphs are part of the scientific story, not just bookkeeping. Yu’s review 2025 study
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
