Statue of liberty original color | Why is the Statue of Liberty green?

Today, the Statue of Liberty is one of the most famous symbols of the United States of America. Do you know why it is blue-green. Today we will try to answer this question in detail.

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What color is the Statue of Liberty?
The answer to this question is simple, right? The Statue of Liberty is greenish in color. But… it hasn't always been like that.

The green color of the Statue of Liberty is not due to any type of paint ... but to rust.

The Statue is covered by sheets of bronze, a material that in contact with acid rain (rainwater contaminated with atmospheric pollution), created a layer of oxide, called “ Verdigris ”, which gives it that characteristic blue-green color. Before this oxidation process, the original color of the Statue of Liberty was a brilliant reddish brown. Most of the copper statues located outdoors end up acquiring this tone after a process known as patination.

During the eighties, the monument underwent a deep restoration. However, the oxide layer was respected as it forms a protective covering against corrosion. If removed, the exposed surface would rust again.

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Statue of liberty original color | Why is the Statue of Liberty green?

Statue of liberty original color:

The Statue of Liberty is the canonical symbol of freedom and the United States of America. The famous monument is traditionally blue-green in color. But it turns out that the color of the statue was not always the same. When Ludvík Svoboda arrived from France to the United States, it was coppery reddish brown. Over the next 30 years, the color of the statue under the influence of air changed, first to chocolate, and then to green.

The reason for this is the oxidation process of the copper that covers the statue. Copper reacts with atmospheric oxygen and, when oxidised, changes color. The process was a series of chemical reactions that lasted for 30 years, after which the statue acquired its current greenish-blue color.

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statue of liberty color change - video:

The American Chemical Society released a video (see below) that showed how the color of the Statue of Liberty, one of the most famous monuments in the world, changed.

New York's iconic blue-green Statue of Liberty hasn't always been this color. When the monument was brought to the United States from France in 1885, it was bright copper.

A new video shows how chemical reactions involving oxygen and air pollution led to the statue's discoloration.

The Statue of Liberty is a gift from France. The monument immortalized the US struggle for independence, and also highlighted the French's own desire for democracy.

A video published by the American Chemical Society explains that the 93-meter statue took 9 years to build. The iron "skeleton" of the monument is covered with pieces of copper "skin". The statue is made of 30 tons of copper - that would be enough. to melt 435 million British pence.

“The first few years in the Big Apple, the statue slowly changed color from shiny copper to dull brown and eventually turned blue-green, or, as they say in France, verdegri,” says the announcer on the video.

statue of liberty color change video

Officials offered to restore the original color of the Statue of Liberty, but the public was against it.

The color change of the statue is the result of an oxidative reaction between copper and air. The color change process took about 30 years. The polluted air of New York also contributed to the color change of the statue.

During the first chemical reaction, copper donated electrons to atmospheric oxygen. As a result, a pinkish-red colored cuprite mineral was formed. Then cuprite lost even more electrons due to oxygen, and a new mineral, tenorite, was formed. The tanneries black color explains why the statue has become darker. Further, chemical reactions occurred due to the interaction of sulfur with water. Sulfur is produced by natural processes such as volcanic eruptions and emissions from boats, cars, aircraft and factories. When sulfur oxide in the atmosphere reacts with water, sulfuric acid is produced. Sulfuric acid combines with copper oxides to form green minerals. So the sulfuric acid in the atmosphere made the statue green. In addition, chloride from the sea spray that hits Ellis Island, where the statue is located, made it even greener.

In this form, the Statue of Liberty has been standing for over 100 years, as copper is oxidised and stable. But in any other place its color would be different.

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How did the color change

The modern Statue of Liberty has a greenish-blue color. This color is typical for old copper objects that have oxidised due to long exposure to oxygen. Many copper monuments and old coins have exactly the same color. Specialists even came up with a special term for it - patina.

Statue of Liberty before oxidation Initially, the design was ... brown-red! Yes, yes, the iron frame was sheathed with thin sheets of copper - about 2.5 mm thick. But soon after the installation, the reaction started - moist, salty air from the sea, together with emissions from New York factories, did their job. As a result, in just 30 years, the entire surface of the statue changed its chemical composition - from copper to copper oxide, which is just characterized by a bluish-green color. After that, the composition became stable and the color did not change anymore.

By the way, the New York authorities from time to time offer to clean and return the statue to its original appearance, but the townspeople do not support the idea, preferring the appearance of the main symbol of the city familiar from childhood.

Why is the Statue of Liberty green?

The Statue of Liberty did not always have such a specific color when it was opened, and this happened back in 1886, it had a rich and shiny brown color. Until 1905, its color changed to green. The color change of the statue took place because its outer surface is completely covered with hundreds of copper sheets. Copper reacts with air and forms a specific greenish film called patina. This film protects the base metal from further corrosion and degradation, which is why copper sculptures are so strong.

The color of the Statue of Liberty is due to the unique environmental conditions as it is not only due to the reaction between copper plates and oxygen. Copper oxide that formed on the surface of the plates continued to react and through this copper carbonates, copper sulfide and sulfate appeared on the surface.

What chemical reaction made the statue of liberty green

There are three main compounds that form a blue-green coating:

Cu4SO4 (OH) 6 (Brocha Tite green), Cu2CO3 (OH) 2 (Malachite green) and Cu3 (CO3) 2 (OH) 2 (Azurite blue).

Here's how they formed:

First, copper reacts with oxygen from the air and a redox reaction occurs.

2Cu + O2 → Cu2O (pink or red)

Then the formed oxide continues to react with oxygen with oxygen and CuO is formed.

2Cu2O + O2 → 4CuO (black)

At the time the Statue of Liberty was built, there was a lot of sulfur in the air as large factories very polluted the air when burning coal. Sulfur, in turn, also reacted with copper:

Cu + S → 4CuS (black)

CuS reacts with carbon dioxide (CO2) from the air, and since the statue is located on a small island in the middle of the water, three more compounds are formed under the influence of high humidity:

2CuO + CO2 + H2O → Cu2CO2 (OH) 2 (green)

3CuO + 2CO2 + H2O → Cu3 (CO3) 2 (OH) 2 (blue)

4CuO + SO3 + 3H2O → Cu4SO4 (OH) 6 (green)

The patina that appeared on the surface of the Statue of Liberty gives it a specific blue-green color, which appeared due to the humid air and high sulfur content.

In 1906, it was proposed to paint the Statue of Liberty, and even a whole project was developed, but this caused great outrage among the public and, therefore, the statue has never been painted to this day.