# MPEP § 2173.05(t): Chemical Formula

> Federal · Agency guidance · In force

URL: https://www.frixlaw.com/law-library/statutes/MPEP_S2173.05(t)

## Section

- **Citation:** MPEP § 2173.05(t)
- **Heading:** Chemical Formula
- **Jurisdiction:** Federal
- **Kind:** Agency guidance
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** USPTO MPEP / Chapter 2100 - Patentability / MPEP § 2173.05(t)

## Text

Claims to chemical compounds and compositions containing chemical
compounds often use formulas that depict the chemical structure of the compound.
These structures should not be considered indefinite nor speculative in the absence
of evidence that the assigned formula is in error. The absence of corroborating
spectroscopic or other data cannot be the basis for finding the structure indefinite.
See
Ex parte
Morton,
134 USPQ 407 (Bd. App. 1961), and
Ex
parte
Sobin,
139 USPQ 528 (Bd. App. 1962).
A claim to a chemical compound is not indefinite merely because a
structure is not presented or because a partial structure is presented. For example,
the claim language at issue in
In re
Fisher,
427 F.2d 833, 166 USPQ 18 (CCPA 1970) referred to a
chemical compound as a “polypeptide of at least 24 amino acids having the following
sequence.” A rejection under
pre-AIA 35 U.S.C. 112
, second
paragraph, for failure to identify the entire structure was reversed and the court
held: “While the absence of such a limitation obviously broadens the claim and raises
questions of sufficiency of disclosure, it does not render the claim indefinite.”
Chemical compounds may be claimed by a name that adequately describes the material to
one skilled in the art. See
Martin
v.
Johnson,
454 F.2d 746, 172 USPQ 391 (CCPA 1972). A compound of
unknown structure may be claimed by a combination of physical and chemical
characteristics. See
Ex parte
Brian,
118 USPQ 242 (Bd. App. 1958). A compound may also be
claimed in terms of the process by which it is made without raising an issue of
indefiniteness.

## Nearby sections

- [MPEP § 2103 Patent Examination Process](https://www.frixlaw.com/law-library/statutes/MPEP_S2103.md)
- [MPEP § 2104 Requirements of 35 U.S.C. 101](https://www.frixlaw.com/law-library/statutes/MPEP_S2104.md)
- [MPEP § 2104.01 Barred by Atomic Energy Act](https://www.frixlaw.com/law-library/statutes/MPEP_S2104.01.md)
- [MPEP § 2105 Patent Eligible Subject Matter — Living Subject Matter](https://www.frixlaw.com/law-library/statutes/MPEP_S2105.md)
- [MPEP § 2106 Patent Subject Matter Eligibility](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.md)
- [MPEP § 2106.01 [Reserved]](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.01.md)
- [MPEP § 2106.02 [Reserved]](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.02.md)
- [MPEP § 2106.03 Eligibility Step 1: The Four Categories of Statutory Subject Matter](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.03.md)
- [MPEP § 2106.04 Eligibility Step 2A: Whether a Claim is Directed to a Judicial Exception](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04.md)
- [MPEP § 2106.04(a) Abstract Ideas](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(a).md)
- [MPEP § 2106.04(a)(1) Examples of Claims That Do Not Recite Abstract Ideas](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(a)(1).md)
- [MPEP § 2106.04(a)(2) Abstract Idea Groupings](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(a)(2).md)
- [MPEP § 2106.04(a)(3) Tentative Abstract Ideas](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(a)(3).md)
- [MPEP § 2106.04(b) Laws of Nature, Natural Phenomena & Products of Nature](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(b).md)

---

Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/MPEP_S2173.05(t). Check the current official text before relying on it. Not legal advice.