Molecular Structure:

Molecular Formula: PbS
Molecular Weight: 239.265
IUPAC Name: Copper hydrate
Synonyms of Copper (I) oxide (CAS NO.1317-39-1): Copper oxide (8CI,9CI) ; Copper oxide (Cu2O) ; Dicopper oxide  ; Cuprous oxide
CAS NO: 1317-39-1
Classification Code: Agricultural Chemical ; Fungicide, bactericide, wood preservative ; Molluscicide ; Reproductive Effect
Melting point: 1232 °C 
H bond acceptors: 1 
Freely Rotating Bonds: 2
Polar Surface Area: 9.23 Å² 
Boiling Point: 1800 °C
Density: 6 g/mL at 25 °C
Index of Refraction: 2.705
Flash Point: 1800°C
Form: powder
Water Solubility: practically insoluble 
Sensitive: Air & Moisture Sensitive
Merck: 14,2664
Stability: Stable. May be air or light sensitive.

 Copper (I) oxide (CAS NO.1317-39-1) is commonly used as a fungicide, a pigment, and an antifouling agent for marine paints.

Reported in EPA TSCA Inventory. Copper and its compounds are on the Community Right-To-Know List.

Hazard Codes of Copper (I) oxide (CAS NO.1317-39-1): Xn,N,F
Risk Statements: 22-50/53-51/53-11
R11: Highly flammable. 
R22: Harmful if swallowed. 
R50/53: Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment. 
R51/53: Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment.
Safety Statements: 22-60-61-16-7
S7: Keep container tightly closed. 
S16: Keep away from sources of ignition. 
S22: Do not breathe dust. 
S60: This material and its container must be disposed of as hazardous waste. 
S61: Avoid release to the environment. Refer to special instructions / safety data sheets.
RIDADR: UN 3077 9/PG 3
WGK Germany: 3
RTECS: GL8050000
PackingGroup: III
Moderately toxic by ingestion. Experimental reproductive effects. A fungicide. Violent, potentially explosive reaction with concentrated peroxyformic acid. Violent reaction when heated with aluminum.

ACGIH TLV: TWA (fume) 0.2 mg/m³; (dust, mist) 1 mg(Cu)/m³

For occupational chemical analysis use NIOSH: Copper, 7029; Elements, 7300.

Copper (I) oxide is one of the principal oxides of copper, and is a component of some antifouling paints. In the history of semiconductor physics, it is one of the most studied materials, and many experimental observations and semiconductor applications have been demonstrated first in this material: Semiconductor ; Semiconductor diodes ; Experimental demostration of Wannier exciton series ; Polariton propagation beats in a solid ; Dynamical Stark effect of excitons ; Phonoritons. Today, it is still under investigation in semiconductor optics. It is hazardous, so the first aid measures and others should be known. Such as: When on the skin: first, should flush skin with plenty of water immediately for at least 15 minutes while removing contaminated clothing. Secondly, get medical aid. Or in the eyes: Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Then get medical aid soon. While, it's inhaled: Remove from exposure and move to fresh air immediately. Then you have the ingesting of the product: Wash mouth out with water, and get medical aid immediately.
In addition, Copper (I) oxide (CAS NO.1317-39-1) could be stable under normal temperatures and pressures. You must not take it with incompatible materials, exposure to air, and it should be exposured to moist air or water. And also prevent it to broken down into hazardous decomposition products: Oxides of copper.