VC

This function returns a pure component’s critical molar volume by CAS number using available reference and estimated data sources.

Critical molar volume is the molar volume at the critical point and is commonly used in corresponding-states and property-estimation methods.

Excel Usage

=VC(CASRN, method)

• CASRN (str, required): CAS Registry Number for the target chemical (-).
• method (str, optional, default: null): Optional data source method name; leave empty for automatic selection (-).

Returns (float): Critical molar volume in cubic meters per mole (m^3/mol).

Example 1: Critical volume of water

Inputs:

CASRN
7732-18-5

Excel formula:

=VC("7732-18-5")

Expected output:

0.000055948

Example 2: Critical volume of ethanol

Inputs:

CASRN
64-17-5

Excel formula:

=VC("64-17-5")

Expected output:

0.000168634

Example 3: Critical volume of methane

Inputs:

CASRN
74-82-8

Excel formula:

=VC("74-82-8")

Expected output:

0.0000986278

Example 4: Critical volume of benzene

Inputs:

CASRN
71-43-2

Excel formula:

=VC("71-43-2")

Expected output:

0.000256345

Python Code

Show Code

from chemicals.critical import Vc as chemicals_vc

def vc(CASRN, method=None):
    """
    Retrieve the critical molar volume of a chemical by CAS number.

    See: https://chemicals.readthedocs.io/chemicals.critical.html

    This example function is provided as-is without any representation of accuracy.

    Args:
        CASRN (str): CAS Registry Number for the target chemical (-).
        method (str, optional): Optional data source method name; leave empty for automatic selection (-). Default is None.

    Returns:
        float: Critical molar volume in cubic meters per mole (m^3/mol).
    """
    try:
        value = chemicals_vc(CASRN=CASRN, method=method)
        if value is None:
            return "Error: Critical volume data is not available for the provided CASRN"
        return value
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

CASRN *

CAS Registry Number for the target chemical (-).

method

Optional data source method name; leave empty for automatic selection (-).