The Statue of Liberty, a symbol of freedom and hope for millions, hasn't always sported its iconic blue-green hue. When it was first erected in 1886, Lady Liberty actually shone in a warm, reddish-brown color, similar to a new penny.

This coppery shade stemmed from the statue's construction material: thin sheets of copper hammered over an iron framework. However, this gleaming facade wasn't destined to last. Here's the fascinating science behind the statue's color transformation:

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Statue Of Liberty Original Color

Original Color:

When Lady Liberty arrived in New York Harbor in 1886, she wasn't green at all. Her skin was a warm, reddish-brown, the natural color of the thin sheets of copper she was made of. You can imagine her looking a bit like this:

This coppery hue was chosen by the French sculptor Frédéric Auguste Bartholdi for several reasons. It was a symbol of wealth and prosperity in Europe at the time, and it also reflected the natural beauty of the metal. Additionally, the copper was expected to darken over time, taking on a protective patina that would help preserve the statue.

The Green Transformation:

However, the natural aging process had other plans. The copper, exposed to the elements, especially the salty air and rain of New York Harbor, began to oxidize. This reaction, combined with the pollutants in the air at the time, created a green patina called verdigris.

The green color started appearing in the early 1900s and gradually spread across the entire statue by 1906. While some were initially concerned about the unexpected color change, it was soon embraced as part of the Statue of Liberty's character. The green patina not only protected the copper but also gave the statue a unique, weathered look that symbolized her endurance and resilience.

Science Behind the Green:

The chemical process behind the Statue of Liberty's greening is quite complex. Here's a simplified breakdown:

Oxidation: The copper reacts with oxygen in the air, forming a layer of cuprite, a reddish-brown mineral.

Further oxidation: The cuprite reacts with more oxygen and chloride from the sea spray, forming tenorite, a black mineral.

Patina formation: The tenorite reacts with water and carbon dioxide, creating the green verdigris patina, a mixture of various copper compounds like malachite and brochantite.

This patina acts as a protective barrier, preventing further corrosion of the underlying copper. It's also self-healing, meaning any damage to the patina will be naturally repaired over time.

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.

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.

The Green Lady Endures:

Today, the Statue of Liberty's green color is an integral part of her identity. It's a testament to her history, her resilience, and her enduring symbol of hope and freedom.

So, next time you see Lady Liberty, remember the fascinating story behind her color. It's a reminder that even the most iconic landmarks are constantly evolving, shaped by the forces of nature and time.

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