public RangeDomainToken Create( 
   RangeDomainDescription rangeDomainDescription
)

public void CreateRangeDomainSnippet(Geodatabase geodatabase)
{
  // Create a range description with minimum value = 0 and maximum value = 1000
  RangeDomainDescription rangeDomainDescriptionMinMax = new RangeDomainDescription("RangeDomain_0_1000",
    FieldType.Integer, 0, 1000)
  { Description = "Domain value ranges from 0 to 1000" };

  SchemaBuilder schemaBuilder = new SchemaBuilder(geodatabase);

  // Create  a range domain 
  schemaBuilder.Create(rangeDomainDescriptionMinMax);
  schemaBuilder.Build();
}