**NOTICE:** Due to scheduled maintenance at our
Gaithersburg campus, this site will not be available from 5:00 pm
EDT (21:00 UTC) on Friday October 25 until 5:00 pm (21:00 UTC) on
Sunday October 27. We apologize for any inconvenience this outage
may cause.

# mercury monoxide

**Formula:**HgO**Molecular weight:**216.59**IUPAC Standard InChI:**- InChI=1S/Hg.O
- Download the identifier in a file.

**IUPAC Standard InChIKey:**UKWHYYKOEPRTIC-UHFFFAOYSA-N**CAS Registry Number:**21908-53-2**Chemical structure:**

This structure is also available as a 2d Mol file or as a computed 3d SD file

The 3d structure may be viewed using Java or Javascript.**Other names:**Mercury(ii) oxide-
**Permanent link**for this species. Use this link for bookmarking this species for future reference. **Information on this page:****Data at other public NIST sites:****Options:**

## Gas phase thermochemistry data

**Go To:** Top, Condensed phase thermochemistry data, Constants of diatomic molecules, References, Notes

**
Data compilation copyright
by the U.S. Secretary of Commerce on behalf of the U.S.A.
All rights reserved.
**

Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|

_{f}H°_{gas} | 10.00 | kcal/mol | Review | Chase, 1998 | Data last reviewed in June, 1962 |

Quantity | Value | Units | Method | Reference | Comment |

S°_{gas,1 bar} | 57.153 | cal/mol*K | Review | Chase, 1998 | Data last reviewed in June, 1962 |

### Gas Phase Heat Capacity (Shomate Equation)

C_{p}° = A + B*t + C*t^{2} + D*t^{3} +
E/t^{2}

H° − H°_{298.15}= A*t + B*t^{2}/2 +
C*t^{3}/3 + D*t^{4}/4 − E/t + F − H

S° = A*ln(t) + B*t + C*t^{2}/2 + D*t^{3}/3 −
E/(2*t^{2}) + G

C_{p} = heat capacity (cal/mol*K)

H° = standard enthalpy (kcal/mol)

S° = standard entropy (cal/mol*K)

t = temperature (K) / 1000.

View plot Requires a JavaScript / HTML 5 canvas capable browser.

Temperature (K) | 298. - 6000. |
---|---|

A | 8.704561 |

B | 0.307162 |

C | -0.054106 |

D | 0.004601 |

E | -0.086077 |

F | 7.103022 |

G | 67.11350 |

H | 10.00000 |

Reference | Chase, 1998 |

Comment | Data last reviewed in June, 1962 |

## Condensed phase thermochemistry data

**Go To:** Top, Gas phase thermochemistry data, Constants of diatomic molecules, References, Notes

**
Data compilation copyright
by the U.S. Secretary of Commerce on behalf of the U.S.A.
All rights reserved.
**

Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|

_{f}H°_{solid} | -21.70 ± 0.029 | kcal/mol | Review | Cox, Wagman, et al., 1984 | red phase; CODATA Review value |

_{f}H°_{solid} | -21.70 | kcal/mol | Review | Chase, 1998 | Data last reviewed in June, 1962 |

Quantity | Value | Units | Method | Reference | Comment |

S°_{solid,1 bar} | 16.79 ± 0.072 | cal/mol*K | Review | Cox, Wagman, et al., 1984 | red phase; CODATA Review value |

Quantity | Value | Units | Method | Reference | Comment |

S°_{solid} | 16.79 | cal/mol*K | Review | Chase, 1998 | Data last reviewed in June, 1962 |

### Solid Phase Heat Capacity (Shomate Equation)

C_{p}° = A + B*t + C*t^{2} + D*t^{3} +
E/t^{2}

H° − H°_{298.15}= A*t + B*t^{2}/2 +
C*t^{3}/3 + D*t^{4}/4 − E/t + F − H

S° = A*ln(t) + B*t + C*t^{2}/2 + D*t^{3}/3 −
E/(2*t^{2}) + G

C_{p} = heat capacity (cal/mol*K)

H° = standard enthalpy (kcal/mol)

S° = standard entropy (cal/mol*K)

t = temperature (K) / 1000.

View plot Requires a JavaScript / HTML 5 canvas capable browser.

Temperature (K) | 298. - 1000. |
---|---|

A | 6.597211 |

B | 17.58020 |

C | -13.98100 |

D | 4.020792 |

E | -0.015326 |

F | -24.38389 |

G | 20.03540 |

H | -21.69910 |

Reference | Chase, 1998 |

Comment | Data last reviewed in June, 1962 |

## Constants of diatomic molecules

**Go To:** Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, References, Notes

**
Data compilation copyright
by the U.S. Secretary of Commerce on behalf of the U.S.A.
All rights reserved.
**

**Data compiled by:** Klaus P. Huber and Gerhard H. Herzberg

Data collected through February, 1975

Symbol | Meaning |
---|---|

State | electronic state and / or symmetry symbol |

T_{e} | minimum electronic energy (cm^{-1}) |

ω_{e} | vibrational constant – first term (cm^{-1}) |

ω_{e}x_{e} | vibrational constant – second term (cm^{-1}) |

ω_{e}y_{e} | vibrational constant – third term (cm^{-1}) |

B_{e} | rotational constant in equilibrium position (cm^{-1}) |

α_{e} | rotational constant – first term (cm^{-1}) |

γ_{e} | rotation-vibration interaction constant (cm^{-1}) |

D_{e} | centrifugal distortion constant (cm^{-1}) |

β_{e} | rotational constant – first term, centrifugal force (cm^{-1}) |

r_{e} | internuclear distance (Å) |

Trans. | observed transition(s) corresponding to electronic state |

ν_{00} | position of 0-0 band (units noted in table) |

State | T_{e} | _{e} | _{e}x_{e} | _{e}y_{e} | B_{e} | _{e} | _{e} | D_{e} | _{e} | r_{e} | Trans. | _{00} |
---|---|---|---|---|---|---|---|---|---|---|---|---|

Absorption bands in the region 33900 - 36500 cm^{-1}, usually ascribed to Hg_{2}
("wing" bands), were tentatively assigned to HgO by Walter and Barratt, 1929. |

## References

**Go To:** Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Constants of diatomic molecules, Notes

**Chase, 1998**

Chase, M.W., Jr.,
*NIST-JANAF Themochemical Tables, Fourth Edition*,
**J. Phys. Chem. Ref. Data, Monograph 9**, 1998, 1-1951. [all data]

**Cox, Wagman, et al., 1984**

Cox, J.D.; Wagman, D.D.; Medvedev, V.A.,
**CODATA Key Values for Thermodynamics**, Hemisphere Publishing Corp., New York, 1984, 1. [all data]

**Walter and Barratt, 1929**

Walter, J.M.; Barratt, S.,
*The band spectra associated with zinc, cadmium, and mercury*,
**Proc. R. Soc. London A**, 1929, 122, 201. [all data]

## Notes

**Go To:** Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Constants of diatomic molecules, References

- Symbols used in this document:

S° _{gas,1 bar}Entropy of gas at standard conditions (1 bar) S° _{solid}Entropy of solid at standard conditions S° _{solid,1 bar}Entropy of solid at standard conditions (1 bar) _{f}H°_{gas}Enthalpy of formation of gas at standard conditions _{f}H°_{solid}Enthalpy of formation of solid at standard conditions - Data from NIST Standard Reference Database 69:
*NIST Chemistry WebBook* - The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
- Customer support for NIST Standard Reference Data products.