A pressure-temperature (P-T) phase diagram showing the boundaries between solid, liquid, and gas phases of a substance. The diagram includes the triple point where all three phases coexist and the critical point beyond which the liquid-gas distinction vanishes. This is one of the most fundamental diagrams in chemistry and physics, essential for understanding phase transitions and states of matter.
#' anyplot.ai
#' phase-diagram-pt: Thermodynamic Phase Diagram (Pressure-Temperature)
#' Library: ggplot2 3.5.1 | R 4.4.1
#' Quality: 88/100 | Created: 2026-06-08
library(ggplot2)
library(dplyr)
library(tibble)
library(ragg)
# --- Theme tokens (Imprint palette, theme-adaptive chrome) ------------------
THEME <- Sys.getenv("ANYPLOT_THEME", "light")
PAGE_BG <- if (THEME == "light") "#FAF8F1" else "#1A1A17"
ELEVATED_BG <- if (THEME == "light") "#FFFDF6" else "#242420"
INK <- if (THEME == "light") "#1A1A17" else "#F0EFE8"
INK_SOFT <- if (THEME == "light") "#4A4A44" else "#B8B7B0"
INK_MUTED <- if (THEME == "light") "#6B6A63" else "#A8A79F"
GRID_COLOR <- adjustcolor(INK, alpha.f = 0.12)
IMPRINT_PALETTE <- c(
"#009E73", # 1 — brand green (first categorical)
"#C475FD", # 2 — lavender
"#4467A3", # 3 — blue
"#BD8233", # 4 — ochre
"#AE3030", # 5 — matte red
"#2ABCCD", # 6 — cyan
"#954477", # 7 — rose
"#99B314" # 8 — lime
)
# --- Data: CO2 phase diagram (physically realistic approximations) -----------
T_tp <- 216.55 # triple point temperature (K)
P_tp <- 5.18 # triple point pressure (atm)
T_c <- 304.13 # critical point temperature (K)
P_c <- 72.8 # critical point pressure (atm)
# Liquid-gas: Clausius-Clapeyron fit anchored at both triple and critical points
T_lg <- seq(T_tp, T_c, length.out = 100)
P_lg <- exp(10.825 - 1988 / T_lg)
# Solid-gas: sublimation curve, L_sub/R = 25200/8.314 ≈ 3030 K
T_sg <- seq(140, T_tp, length.out = 100)
P_sg <- P_tp * exp(-3030.3 * (1 / T_sg - 1 / T_tp))
# Solid-liquid: near-vertical melting curve, dT/dP ≈ 0.015 K/atm for CO2
P_sl <- seq(P_tp, 2000, length.out = 100)
T_sl <- T_tp + 0.015 * (P_sl - P_tp)
df_boundaries <- bind_rows(
tibble(temperature = T_lg, pressure = P_lg, boundary = "Liquid-Gas"),
tibble(temperature = T_sg, pressure = P_sg, boundary = "Solid-Gas"),
tibble(temperature = T_sl, pressure = P_sl, boundary = "Solid-Liquid")
)
df_boundaries$boundary <- factor(
df_boundaries$boundary,
levels = c("Solid-Liquid", "Liquid-Gas", "Solid-Gas")
)
df_special <- tibble(
temperature = c(T_tp, T_c),
pressure = c(P_tp, P_c)
)
# --- Plot -------------------------------------------------------------------
title_str <- "CO2 Phase Diagram · phase-diagram-pt · r · ggplot2 · anyplot.ai"
p <- ggplot() +
# Phase region fills (semi-transparent, drawn first so lines appear on top)
annotate("rect", xmin = 130, xmax = 219, ymin = 5, ymax = 2000,
fill = IMPRINT_PALETTE[3], alpha = 0.05) +
annotate("rect", xmin = 215, xmax = 305, ymin = 5, ymax = 75,
fill = IMPRINT_PALETTE[2], alpha = 0.05) +
annotate("rect", xmin = 140, xmax = 415, ymin = 0.001, ymax = 73,
fill = IMPRINT_PALETTE[1], alpha = 0.05) +
annotate("rect", xmin = 303, xmax = 415, ymin = 72, ymax = 2000,
fill = IMPRINT_PALETTE[4], alpha = 0.05) +
geom_line(
data = df_boundaries,
aes(x = temperature, y = pressure, color = boundary, linetype = boundary),
linewidth = 1.2
) +
geom_point(
data = df_special,
aes(x = temperature, y = pressure),
shape = 21, size = 4.5,
fill = ELEVATED_BG, color = INK, stroke = 1.5
) +
# Phase region labels
annotate("text", x = 168, y = 80, label = "SOLID",
color = INK_MUTED, size = 4.0, fontface = "bold") +
annotate("text", x = 268, y = 50, label = "LIQUID",
color = INK_MUTED, size = 4.0, fontface = "bold") +
annotate("text", x = 300, y = 0.45, label = "GAS",
color = INK_MUTED, size = 4.0, fontface = "bold") +
annotate("text", x = 370, y = 600, label = "SUPERCRITICAL\nFLUID",
color = INK_MUTED, size = 3.5, fontface = "bold", lineheight = 0.9) +
# Special point annotations
annotate("text", x = 221, y = 12,
label = "Triple Point\n(216.6 K, 5.2 atm)",
color = INK_SOFT, size = 3.2, hjust = 0, lineheight = 0.9) +
annotate("text", x = 308, y = 120,
label = "Critical Point\n(304.1 K, 72.8 atm)",
color = INK_SOFT, size = 3.2, hjust = 0, lineheight = 0.9) +
scale_y_log10(
name = "Pressure (atm)",
limits = c(0.001, 2000),
breaks = c(0.001, 0.01, 0.1, 1, 10, 100, 1000),
labels = c("0.001", "0.01", "0.1", "1", "10", "100", "1000")
) +
scale_x_continuous(
name = "Temperature (K)",
limits = c(130, 415),
breaks = seq(150, 400, by = 50)
) +
scale_color_manual(
values = c(
"Solid-Liquid" = IMPRINT_PALETTE[1],
"Liquid-Gas" = IMPRINT_PALETTE[2],
"Solid-Gas" = IMPRINT_PALETTE[3]
),
name = "Phase Boundary"
) +
scale_linetype_manual(
values = c(
"Solid-Liquid" = "solid",
"Liquid-Gas" = "solid",
"Solid-Gas" = "dashed"
),
name = "Phase Boundary"
) +
labs(title = title_str) +
theme_minimal(base_size = 8) +
theme(
plot.background = element_rect(fill = PAGE_BG, color = PAGE_BG),
panel.background = element_rect(fill = PAGE_BG, color = NA),
panel.grid.major = element_line(color = GRID_COLOR, linewidth = 0.4),
panel.grid.minor = element_line(color = GRID_COLOR, linewidth = 0.2),
panel.border = element_blank(),
axis.line = element_line(color = INK_SOFT, linewidth = 0.5),
axis.title = element_text(color = INK, size = 10),
axis.text = element_text(color = INK_SOFT, size = 8),
plot.title = element_text(color = INK, size = 12, face = "bold",
margin = margin(b = 8)),
legend.background = element_rect(fill = ELEVATED_BG, color = INK_SOFT, linewidth = 0.3),
legend.text = element_text(color = INK_SOFT, size = 8),
legend.title = element_text(color = INK, size = 10),
legend.position = "right",
legend.margin = margin(6, 8, 6, 8),
plot.margin = margin(12, 15, 12, 10)
)
# --- Save -------------------------------------------------------------------
ggsave(
filename = sprintf("plot-%s.png", THEME),
plot = p,
device = ragg::agg_png,
width = 8,
height = 4.5,
units = "in",
dpi = 400
)
Runnable source as JSON, for any HTTP client: https://api.anyplot.ai/specs/phase-diagram-pt/ggplot2/code. Any spec id and library id listed in llms-full.txt fit the same URL shape; every URL below is complete and callable.
{
"spec_id": "phase-diagram-pt",
"language": "r",
"library": "ggplot2",
"page": "https://anyplot.ai/phase-diagram-pt/r/ggplot2",
"hub": "https://anyplot.ai/phase-diagram-pt",
"code_json": "https://api.anyplot.ai/specs/phase-diagram-pt/ggplot2/code",
"spec_json": "https://api.anyplot.ai/specs/phase-diagram-pt",
"render_light_png": "https://storage.googleapis.com/anyplot-images/plots/phase-diagram-pt/r/ggplot2/plot-light.png",
"render_dark_png": "https://storage.googleapis.com/anyplot-images/plots/phase-diagram-pt/r/ggplot2/plot-dark.png",
"quality_score": 88.0,
"license": "MIT",
"guide": "https://anyplot.ai/llms.txt"
}Part of Thermodynamic Phase Diagram (Pressure-Temperature) on anyplot.ai.